Yeah i had to stop, go back and replay ... it's a good thing this channel doesn't have many young viewers "Daddy why do you get an infection if you start in the back"
Just did a 2004 XJ with a 4.0. It had two pistons that dropped their skirts. 279,000 miles. The customer replaced it with a reman. This is a common issue with the High Mileage 4.0s. What happens is as follows. It starts to overheat or run just a bit on the higher side of 220 degrees. The piston skirts crack or break off leading to it burning some oil. The oil soot covers the 02 sensor, and tricks it into thinks it is running rich. So the computer adds timing and lean out the fuel to get it within spec. Only to melt down the already damaged piston, and this is the end result.
A coated O2 sensor will produce a lower than normal voltage which makes the vehicle think it's running lean, the computer will add fuel so the vehicle will be running rich, not lean.
thats good to know..... when it got around 110F in NE montana this summer..... my 97 was running at about 217 (used OBD2 scanner) which is just a needle over straight up and down . she hit 227 pulling up "kittleson hill" on my 100 mile daily commute . no noises, oil burning, or death yet..... but i was REALLY worried about it turned off the AC, ran the heater.......knowing that number 6 was probably WAY over 227..... . i love my Heep..... its a POS.... but its got soul
Finally a 4.0 teardown! And my god I've never seen that damage to a 4.0 in my life. I daily a 1995 Jeep Cherokee with 254K on it and it runs pretty nicely.
When I was a teen my mom had an 1987 AMC jeep Cherokee with the 4.0 and it had over 300k on it the trans had been rebuilt but motor was unopened besides remain seal and valve covers along with intake and exhaust manifold being redone. Thing was reliable only issue we ever had with it was a upper radiator hose blowing while we're were on the road used a knife cut the bad section out put water in it till we got home and it was good.
Fun fact. This engine was designed by engineers from all the big three makes. AMC came around and they stuck this in about everything. When AMC disbanded Chrysler kept using the engine. It has one of the longest production life spans of any engine.
I owned a 97 Cherokee with the 4.0L. After 212k miles the engine still ran strong. Like you said, everything around the body was falling apart or broken, but the engine always started up.
I have a 2001 XJ and it has been rattling for eight years, so bad I tell people that it's a Cummins swap. I paid a mechanic to drop the oil pan and take a peek. He couldn't find any loose so he buttoned it up and said to just ignore the rattle and keep driving it. That was eight years ago.
I bought a 1996 Grand Cherokee with 267,000 miles on it. It was my first Jeep. It had a slight tapping coming from Cylinder #6. Started using T4 10/40 in it and it quieted it substantially. Drove it till about 301,000 miles and then it developed a really loud chatter. Still drove it another 2,000 miles that way till I finally bought another vehicle. I got curious and dropped the oil pan. The piston skirt for cylinder #6 was laying in the pan. Engine still ran and had good compression. Just piston #6 was chattering around in the cylinder.
Had a 99tj with about 90k on it break a skirt on the piston on cyl 6. Thought it was a rod knock at first. Pulled it and tore it down. Found the rod on cyl 4 visually bent as well. Never hydrolocked it. Figured I had it apart so go big or go home. Went .030" over, stroked it with a 4.2L crank, Comp Cams camshaft, bigger injectors amongst exhaust and others. I was very happy with the build!
I've seen that kind of damage in 4.0L in-line 6 before. The 2 main reasons are 1) Prolonged high revving from trying to get unstuck in deep mud, or 2) very steep angles during rock crawling. I have owned many Jeep (Chrysler models) over the last 35+ years. Being involved with off-roading clubs has given me experience with the typical failures for people pushing their vehicles to the failure point.
For a piston skirt failure, that one actually seems pretty tame. Usually the piston comes apart and the wrist pin hammers into the block until it either makes an inspection port or it seizes.
@BB Sky it doesnt, which is exactly the problem. The piston around the wrist pin comes apart, and the rod starts hammering it into the sides of the bore until either the engine gets an inspection port, the rod lets go or the engine seizes.
I like the 4.0 because of it's AMC lineage. But those cracks in the head you saw are common on certain years, and that's Chrysler's fault, because they redesigned the head. After a couple of years, they saw the common failure pattern, and came out with yet another redesign that fixed the cracking problem.
The most crack-prone heads are just from the start of the distributorless ignition until late 2000. The head casting with the improvement has the letters TUPY cast under the valve cover, but it’s still not quite as good as the 1999 head. IMO, 1999 is the single best year of the 4.0. It has all the strengthening and improvements to the crank and block that Chrysler made over the early kinda flexible AMC design (including the main cap spine),still has the tubular header, has the improved intake manifold, has the best ECM programming, but doesn’t have the issues that came with the head when it was redesigned for the coil rail mounting needed for DIS.
Best part about 97-99 is they don't have any of the advanced emissions Jeep used to try and eek out more lifetime. Just the one O2 sensor, single bank of six exhaust (which will always crack), distributor, so so so easy to work one. You can do the entire ignition (plugs, wires, cap, etc) for a third of the cost of coil packs.
Just did a full rebuild on my 2004 WJ 4.0 after It broke a piston skirt. I bought It last July as a winter vehicle and It had a rattle and I couldn't get It to go away. Everyone said It was completely normal for a 4.0 to rattle. I tried everything on the internet to get rid of the rattle, tried using a oil filter that held more oil and still nothing. Noise was always the same but would go away when fully warmed up. But come back on a cold start. It got me through a whole winter of beating on It and was using It as a a backup one summer day and was ok the highway and the rattle turned Into a knock. Drove straight home and parked It. Thought a lifter had gave up and tried thicker oil and even Lucas oil and nothing made the noise get quieter. That's when I knew It was an Internal problem. Started tearing It apart and found cylinder 4 with a broken piston skirt. Did a full rebuild and now you can't even hear that It's running. It's been back together about 5 months and I've made It my daily even before winter started and I do not baby this engine except on maintenance. I did all the piston upgrades, moly pistons, moly rings all new bearings. Hardest part of the whole job was getting the intake and exhaust manifolds off while It was still In the Jeep. When putting It back together, I Installed the manifolds onto the head before I put It back In the Jeep. So much easier, but extremely heavy and would recommend a 2nd person to help lift onto engine.
Had the same 4L in a jeep Wrangler in the shop this past year, thing had completely seized, and when we pulled the pan there was mud in it. When asked, the owner denied having driven it in water or anything. We sent it away for a complete revision along with boring it out into a 4.6L. It now makes 300 hp and 600 Nm of torque.😁 Was quite a fun project. Had to modify and rebuild the entire jeep as it wasnt roadworthy anymore. One hell of a project for me and another mechanic, but a lot of fun
The 4.0 "AMC" and Furrrrd's 4.9 300 straight 6 are both legendary in similar ways. I had a '81 Bronco with the 300 and a manual 3-speed ( with overdrive) that was one of my favorite trucks ever! 300,000 miles on that truck. Too many things went wrong too quickly on the Bronco so I sold it as a parts truck. The 4x4 still got me anywhere I needed to the very end. 🏁
I daily a 1984 F150 with a 300... very durable engine indeed. Rebuilt it back in 2020 due to bad rings/bores (lots of blowby); despite that, it was still running somewhat decently. The rebuild was its reward for getting me though a long trip I didn't expect to drive it on... well earned!
I've been hounding Eric to get his hands on a 300 for a teardown but they're so fucking reliable that cores never show up haha. I have an 85 and a 95 F150, both with that engine, both with manuals. Love 'em both.
@@TestECull We used to run F-150s with the I6 300. Mostly highway, with some local parts running. Manual transmissions. We never had to replace an engine, and some of them had well over 300,000 miles. They got three times the mileage of the oldest truck we had with a 460 under the hood. That 460 was bomb-proof, too.
@@dougrobinson8602 Best OHV engine Ford ever sold. Pulls like a 302 on a third less gas with a life expectancy measured in decades because odometers dont go high enough 🤣🤘
My brother had one of these in a jeep that had over 200k. It had a cracked radiator so he'd have to refill it. Sometimes he would drive longer than 30 minutes without coolant and the temp pegged on H and when he got home it would be bone dry. Drove like this for a few months. He had it for a year more and sold it to the neighbor who had it for years. Have to work hard to kill a 4.0
I've currently have 4 from 91-05 one of unknown year in my 90XJ it was replaced twice in the past warranty replacement first the second was due to bad replacement oil pump. Solid engines with simple upkeep on oil, coolant and plugs
Yes, Finally!!! My favorite engine too. In fact, I'm dailying my 04 WJ at the moment because well, it's the only thing I own that doesn't ever break. From what I remember, somewhere around 2000-2002 were the problem years with cylinder heads cracking, at least for the WJ. By around 03 and definitely for all 04's have a different head (denoted by the "TUPY" stamping under the oil fill cap) that isn't prone to cracking. I'm 32 and I expect my 4.0 to outlive me!
So glad to see the 4.0 inline 6. They are so hard to find as cores. One of the best engines ever made. Would still love to see a GM 3800 series engine on the channel, or a 3.5L V6 from the 93-97 Intrepids/Concords
My family had both of those. The 3800 Vortec was BULLET. PROOF. The 3.5 was fine enough, but the transmission that rode behind it was garbage. Lost reverse out of it at 36k miles.
@@dougrobinson8602 the Achilles heel on the later 3800 engines was the plastic intake plenum, which was notorious for getting brittle and cracking, which would dump coolant into the engine. If you buy any car with one of those engines, make sure you replace that part right away.
Can't remember the year for the water pump change , but if memory serves me when jeep went to serpentine belt the water pump went reverse rotation but the old pump will still fit . May be part of the problem , wrong rotation will still move some water but not enough .........
Sold mine after 350,000 miles and it still ran great. It was the family adventure vehicle. Heavy loads and back country roads were no problem for our 1995 sport. It did have a cracked exhaust and after my son used it two of the engine mount studs were cracked. I welded the engine mount back to the studs and it was good to go.
Thank you! Another one off the list! This engine is, of course, one of the most durable and torquiest motors available from the late seventies through the early aughts. The inherent primary and secondary balance of the straight six aside, just the combination of torque, ease of maintenance, and simplicity all made it the absolute pinnacle of the Wrangler powerhouse. This engine is still the best 6 cylinder that has ever been in a Chrysler product (slant six aside), and I have a couple customers that have their Grand Cherokees and wranglers up past 300K. Having to drop the 242 and the 318 from their lineup has left FCA continuing to fight for a 6 or 8 cylinder gas engine of any sort of quality, a fight that to this day has not been won. Yes, I know what I said. The Gen 3 hemi is barely worth its weight as a boat anchor. Of course you're not going to have a problem with the dipstick tube - it's not on a GM product. Engine Requests: Ford: 300 Inline Six, Windsor, FE, 1.0 EcoBoost, 1.4 EcoBoost, 5.2 Voodoo, 6.7 PowerStroke General Motors: 3100/3400/3800 Olds, LUW/LWE 1.8l i4, L5P Duramax Chrysler: Slant Six, MORE HEMIS, 1.4L FIRE, 3.3/3.8, 318/360 Honda: B Series, D Series, K Series Toyota: 1GZ-FE, 1ZZ or 2ZZ Subaru: FJ series, EZ30/36 Other: DT466 Old School Unicorns: GM 702 Twin-Six, Oldsmobile 5.7 Diesel, LT5 Lotus (C4 ZR1) Modern Unicorns: Toyota 1LR-GUE, Chevrolet Gemini, 7.3 Godzilla
He has an EZ36 on the shelf/rack to his left our right when he shows the other 4.0 on the ground. I know it's a 36 because the intake runners are huge. I doubt he will take it apart but it'd be nice. Those EZ are not easy to disassemble. Even worse to get together.
And Olds 5.7 diesel would be cool to see, but they're rare. An LT5 is rarer yet. That was the best DOHC GM ever built and how they got the Northstar from it is beyond me.
The later 4.0L engine built between 1999 and about 2002 used a head casting #0331 and was prone to cracking between the 3rd and 4th cylinder due to the exhaust port redesign to meet emissions. This same head casting #0331 was redesigned and they added a TUPY casting mark on the surface of the head just under the oil fill cap. The head with the TUPY marking was corrected to prevent this cracking. The #7120 casting between about 1996 and 1999 I believe is the best for performance as it was less restricted before the emissions redesign.
I really appreciate how you speed through repeated bolt removal once the initial fastener is dealt with like on heads and rockers. Very enjoyable and informative stuff!
When you rotated the engine and all of the tappets fell out it brought back fond memories of my 83 CJ7 and it’s lifter problems. Still runs great today.
The cylinder head definitely feels like 89 lbs when you are leaning over the front of the jeep or the fender to remove it and even more when you are putting it back on
There was a little known issue with water pumps. The inline sixes had 2 water pumps. V grove turned one way. Serpentine turned opposite. They could easily be switched and the coolant would not circulate properly causing meltdown of the center two pistons.
There is a clear crack in the cylinder head, between #2 and #3 rocker arms. It can be seen just by removing the oil fill cap and looking in the valve cover. I was a jeep tech in the early 00s, this was very common on 98-03 cylinder heads. I replaced hundreds under warranty.
Had a 95 GC with the 4.0 with 325k when I sold it. Only problem I ever had with was the water pumps shreading every 20-30k miles. I got very good at that routine maintenace.
Just replaced a 02 with 112000 miles for the same thing customer thought he had a lifter problem engine ticked. Dropped the pan and no skirt on # 3 and 5 pistons common problem. jeep dealer told owner you have a 50/50 chance you got one with defective pistons! Engine was spotless inside well maintained as clean on top as on the underside.
One time I pulled apart a 4.0 from like a '92 Comanche and it had been run at least 60 miles distance with pieces of a broken valve riding bouncing around inside a cylinder. Top of the piston all scarred up and walls not perfect. I ground the top of the piston with a dremel tool, threw on the rebuilt cyl head, and it ran perfect for over 10K miles until I sold her.
A mechanic friend told me a story about one of his customers that had towed a Cherokee using a front axle type dolly for about 50 miles and then remembered that he had forgot to take the trans out of low gear and then found the engine wouldn't start. He pulled the head and ALL pistons were missing- just con rods and wrist pins were left...
@@spasticslug2932 Yeah, you’d ruin the transmission and that’s about it. The only possible way that story would hold water was if it was a straight shift left in 5th gear, and even then it’s not gonna do what he said it would, especially just after 50 miles.
BS… unless it had no serpentine belt on, if the crank was turning the water pump would be turning, if the engine got warm enough the thermostat would open and the radiator would cool the engine just the same as if it was running. But more than likely it would just drag the rear wheels…
I've repaired quite a few of those with piston skirt failure. Overheating doesn't help things either. They start making a thunking noise like tapping on a tin can at idle when they start failing. Those can be repaired with a set of pistons and rings. I always opted to do the timing chain and bearings. They literally run for ever if you catch it early. The last one I did was a 2001. Thanks!
I have a 2001 Cherokee that used to be a cop car until 100,000 miles. I bought it at 130,000 and by 135,000 the engine had no power at all. Wouldn’t even climb hills. Took it to a shop and they said it was a miracle it even made it there. It was just a worn out girl that needed replaced.
My son bought a 2004 Grand Cherokee with the 4.0 and drove the hang out of it. I got it and drove the hang out of it then gave it back to my son, and he drove the hang out of it then gave it to his father-in-law, and now he's driving the hang out of it. The computer is starting to go away, but the engine's been solid.
I’m a technician and to be honest I’ve had nothing but bad luck with the Chrysler 4.0. Sad by true. Always overheated or head warped it’s always a bad egg. Piston slap as well.
Don't trash that block! It may be suitable for an overbore as long as there are no cracks in it. Someone might be interested in buying it for a stoker build.
Finally! I'm glad you finally made a video on this engine. The 4.0L is the only good thing about my jeep and it still isn't perfect. I just read the description and my uncle has a 2004 WJ grand cherokee with over 350k miles it takes literally a minute of cranking but it still starts and runs
@@alexstromberg7696 Ummm no. It makes about 200hp stock and stokers can make 300+ hp. Why do some people always feel the need to comment on things they know literally nothing about?
My 4.0 in a 2004 Jeep Grand Cherokee with 120,000 miles with oil changes every 3000 miles started making noise. I drove it to an engine shop 40 miles away. They dropped the oil pan and it was full of piston parts. The shop didn't know how I was able to drive it 40 miles. I had them put in a new crate engine, replace the water pump, radiator, hoses, etc. I have around 250,000 on it now and just finished up replacing all my suspension parts in my garage. (Glad I don't live in the rust belt!)
That version of the 4.0L was used in the 2000-2006 jeep wrangler, and the 1999-2004 grand cherokee, I can tell by looking at the water pump and the accessory drive
I have a 2006 Golden Eagle 4.0, C.J. auto trans, a/c just turned 60,000 miles, still runs like new. I'm a service nut and stay up on servicing it. Changed the water pump and thermostat and hoses at 50,000 mi just because of age...Love that Jeep!
Can you imagine going in for a physical exam and your doctor making the same noises as Eric does when he examines this engine block?!?! (Hmmm....maybe it wouldn't be that funny after all. 😱)
I was just thinking of a surgeon musing to himself "Hmmmm-hmmmm. Looks good. That's good. Oh, *that's* not supposed to be there!" Actually, considering the context (that 4.0 was very thoroughly deceased) probably an ME.
Got a 97 with an old trw 5.0l stroker kit and a hesco aluminum head. Threw on an m90 blower and a pacesetter header blowing through a dual 2 3/4 exhaust. Sounds awesome and just will not die!
UK mechanic here, I absolutely love the channel, I'm addicted. You do a lot of complicated big blocks I would love if you could do some small European engines like some small inline 4 cylinders as that's mainly what we drive over here and their an absolute breeze to teardown and rebuild 😊
Since the cylinder head cracks line up with the most damaged pistons, I'll guess coolant was getting into those cylinders causing detonation, which leads to the torched pistons. I'm impressed the pistons didn't come apart with how loose they were on the wrist pins!
I'm a retired mechanic of over 30yrs. and current 4.0L owner and I've replaced over a dozen exploded 4.0L in my career. Leave them stock and drive them gently or they Will break. That's the advise I've learned to give.
@@RANDOMNATION907, huh, driven the hell out of my current XJ with a 4.0l, and it's at 280k miles without a single issue. Where the 4.0l runs into issues are the late 1996-2006 (2001 for the XJ). These engines have some know issues with severe overheating from a flawed head design and piston skirt failures causing engine failure.
@@JohnGarcia-ii8lb, 1997-2004 (last year of the 4.0l) is known to have weaker piston skirts... even then, I haven't seen one experience this level of destruction.
31:54 When I did a head gasket job on my 85 F150 many moons ago I didn't even ATTEMPT to manually lift the head. I got the cherry picker in there to lift it out, and it lowered it back in with the cherry picker. There is ZERO chance I will ever be able to get that three foot long lump of cast iron off the block, over the fender/core support, and onto a work table without throwing my back out.....
My daily driver is a 94 cherokee with a fresh 4.0. The issue I have was a used torque converter that leaks at the seal, as a very slight wear groove and where I installed a sleeve as round two. And where a driveway leak is problematic and waiting for a full trans refit. As for the rest of the body, I really like the simple, long lasting functionality. Very solid . Thanks for the full view to engine. M.
You magnificent madman, you finally got one for us! I've owned many Jeeps with the 4.0, XJs and ZJs both, so this is going to be fun. Besides piston skirts and the TUPY heads, these were solid. Although the cooling system was rather inadequate in the XJ, application. You have to ON TOP of cooling system maintenance on those. ZJs were a clean sheet design, so the 4.0 was integrated correctly in those from the get go.
My 02 wj never gets hot, has 220k on it and I drive it up north n back 400 miles both ways in extreme heat and stop and go interstate congestion. Never runs hot, always on top of oil changes I do myself with pennzoil and Fram filters everyone hates for some reason. I've ran Fram my whole life never had an issue, I also use Lucas oil treatment.
I've found on my XJ, that you just replace the entire cooling system every 4-5 years. There's two Achilles Heels: 1) the viscous fan clutch wears out 2) the radiator fills up with sediment. As long as you shotgun the whole thing, and give it a good flush, it's really no problem.
@@lustfulvengance I don't have a specific answer, but most people agree it's a materials/design issue (dimensions of the skirt). It also affected the 4.2 inline 6, the 4.0s predecessor. My understanding is that it officially only affected about 6% of all units, although reality could be different. When you consider literally millions of these were produced, 6% or more is a decent figure.
@@litz13 I think the sediment thing is due to mixing coolant. I've had it in my XJ, but since the last time I replaced the radiator and gave the whole system a good flushing I've stuck with plain, old fashioned green coolant and stayed away from the universal stuff. My 4.0 runs nice and cool, even in the summer with the AC on.
04:38 "This water pump looks like new and would be a good backup" then sounds of the water pump being tossed unceremoniously across the room. This is why I love this channel.
Since that engine development was started in 1956 by Nash, then it was made by Hudson, then made by Rambler, then made AMC, then made by Chrysler for Jeep… After 50+ years, they better have figured out how to make it work right!
@@nuttfarmgarage6434 the early engine was changed repeatedly to make improvements. Just 'cause new parts don't fit old junk doesn't mean the whole thing is different. One step leads to the next, and you can't get to the top without climbing the steps.
@@brandonupchurch7628 Last I looked 1964 was before 1965. The 232 was introduced in the special edition 1964 Rambler Typhoon. The article in Wiki even has a picture of the car and the license plate says "1964".
I had a guy drive his wifes 99 jeep Cherokee 25 miles into the shop the 4.0 ran decent but had a miss never made any noise but when we pulled the head off #6 piston was gone!! didn't scar up the cylinder at all we dingle berried the thing put a new piston and wrist pin on the rod reused the rod bearing because it still looked great and she's still driving it today 3 years later. The head casting on these are junk. But with much needed radiator upgrades these will last for a long time. AND A 180 DEGREE THERMOSTAT IS A MUST!!!
👍 thanks for making me feel better about my 4.0 with 319k miles on it! It's had a oil leak on the last 2 cylinders coming out the head gasket for about 60k miles. It's always been on my "I'll get around to it..." list.
My brother had a box style Cherokee, with the high output, I think they called it, it had over 300,000 and ran like new! You couldn't kill it, he traded it in on a new car.
I had a piston melt through on my 5.0L Ford V8. Heard the sound of (what I now associate with) pinging when under load and it finally let go while towing a load of hay for a friend. Had to drive it another 25 miles before getting it home, blowing smoke the whole way. Looked exactly like the one you pulled out of this 4.0L. The fix was an in-frame piston replacement, complete with a stone hone to knock off the extra aluminum spray and somehow a much thicker wrist pin than what's on the rest of the rods. So it's got a tiny shake at idle but still runs strong!
Eric, when you disappeared off screen pulling the cam, I expected you to edit it to look like the cam kept going on forever, you know how a magician pulls the endless handkerchief out of his hand,
6:19 If they don't crack, they warp. The Ford 300 does the same thing for the same reason. My 85 F150 will have an exhaust leak for as long as it retains the factory exhaust log because it's so badly warped #1 exhaust port will never even attempt to seal. It's a good thing I don't really care about exhaust leaks haha
Eric, Merry Christmas to you and your family. Thanks for taking us along with you this past year. I’ve enjoyed your videos, your humor and presentation style!
I had a 91 Jeep Cherokee years ago from new. Developed a ticking noise under warranty. They replaced the top end and noise didn’t go away so they replaced the short block. Lasted me almost 400,000 kms before developing a tick so I sold it. Excellent vehicle and easy to work on 😊
I 100% agree with the early exhaust manifolds. I would be replacing at least one a week at the Midas shop I worked at. The replacement ones had a small flex section on the number 1 and 6 pipe to prevent a recurrence.
My 96' grand Cherokee has a V8 5.2L (318). Been awesome rig. The motor was replaced back in 2014 by previous owner, with an '03 dodge dakota motor, bolted right up along with all accoutraments. Jeep is still pretty much stock but is a great driver, all I'vehad to do to itis tires, a few sensors, new alternator. Great vid Eric!!
Your videos keep getting better and better! I love watching you channel, its relaxing and entertaining. Always looking forward to seeing your new tear-downs and project updates. Your commentary is my favorite part lol. Merry Christmas man!
With a flat tappet engine, you can check lifters for wear by placing "flat" ends together and see if they rock slightly. Ends are groundspherical when new.
I have an 00 XJ, the story was it got hot and he parked it, i pulled the head off and the head gasket was blown between cylinders 2, 3, 4, 5, and 6, #5 has rod knock and #4 piston welded part of itself to the wall, amazingly the thing still ran before I pulled the head. I put an mls head gasket and a spare 0663 head I had, still in the process of finishing up. XJ's are one of my favorite vehicles along with GMT800's and W-bodies.
Merry Christmas and a Happy New Year! Thanks for all the humor and jokes throughout all these tear downs and projects! You are like an auto coroner on the channel, but you also save a lot of cars from the salvage yards. You should be called the car doctor for all the autopsies and projects. Keep up the great work!
They are tall, and I guess it's easy to build up air pockets in the top cooling passages of the head. My kid destroyed one driving with low coolant, but a head plane and valve job fixed it. Did new lifters at the same time, and used my old Ford trick of grinding off any wear bumps on rocket arms that might restrict their range, and hand fitting washers under the rockers to compensate for wear and the milled head.
Love this guy! No bs, no flash. just great info. I'm running a 98 ZJ Grand Cherokee Laredo 157K just fought the death wobbles. think I might have got it, finally. KOW
Thank you for the video. I have owned two jeeps now. Both have run hot and burst the radiator. The first a 2000, also spun a bearing and started knockings. (like the motor you showed).The second is a 2004. It ran hot while idling in my driveway. It also burst the radiator. This time I don't think it hurt anything as far as I can tell. But I had enough of the electric fans. I went to a junkyard and pulled the the manual fan off an older jeep and replaced the electric fan. Bing,bang,boom no more problems. I have 134,000 miles now and it runs like new. P.S. I think someone had tried to rebuild the bearing in that motor after it had run hot.
Which is more ... bulletproof, in your opinion. 4.0 L Jeep or 225 CI Slant Six ? Have you torn one of these down. I had one (moons ago) which continuously had 'grey' oil and a leakiny rear main (fill the oil, check the gas). TBH, the oil leak kept the body of the D-150 (A833) frame from rusting. The carbon (1bbl) kept the exhaust from rusting.
My friend had a slat six in his old Dodge dart Swinger. We actually tried to kill it with a brick on the accelerator pedal. It revved up and would not quit. Valve float kept it from revving too high, and we finished off a six pack waiting. Never died.
I am doing a 4.0L rebuild now and the block was in worse shape. That block you have is the perfect candidate for a stroker build, if a .060 Overbore is possible. Mine had lips on all six cylinders where the rings had really dug into wall, like I caught my thumbnail on the lip. That's likely why your pistons 3 and 4 refused to come out, they were catching on a lip. Part of the reason why Cylinders 3 and 4 on the I6 (of any Generation, even on the Rambler) fail is because their exhaust ports are right next to each other and they build up a ton of heat in that region. All AMC style I6 heads can fail here, just on the new head from 2001 on, Chrysler was counting beans. My core was only $100...then I spent $600 at the machine shop getting the cylinders bored and block fluxed.
Had 93 grand Cherokee. Motor was bout shot, so I bought a White Brothers 4.6L kit for it, that thing was a beast! That motor your dismantling is roasted, mistreated bad.. great vid man. Commentary is priceless!!!! Great vids Eric!!
Man you brought me back to the 90's! I was one of the Senior Technicians on this engine at Chrysler Jeep Truck Engineering in Detroit. The 4.0L engines commonly ran 2 to 3 times longer than the target of 1000 hours on durability test.
That is the longest engine I have ever seen! It looks overbuilt, like it belongs in a tractor. The AMC 242ci I6 engine had amazing durability until 2000 when the cylinder head was made too thin. From 2000 to early 2001, cylinder heads were cracking between the #3 and #4 cylinder. However, the cylinder heads marked with, "TUPY," were much thicker than the problematic 0331 cylinder head. It is likely this engine has the problematic 0331 cylinder head.
i have a WJ with the 4.7, honestly kinda happy i dont have the 4.0 yes, its not as bullet proof but its been great. ive even been on lakebeds that have hit 118, and stopped on. freeway when its 124. no heating issues or anyrhing. and its been great. tows good too
I worked as a forester for a large private landowner. I always drove 4X4 Fords, but when it needed maintenance, I would have to drive a Jeep CJ with a straight six. The vehicle was miserable to drive. Cold and wet in the Winter and hot in the Summer. Now, I'm no Jeep expert, but I had a couple of buddies that had CJ's with V8's, one with a 390 AMC and the other had a 343( I think ).They were both better in the mud and logging roads that I traveled daily than the 6 cylinder. The company put some bigger, more aggressive mud tire on the Jeep with a 6 cylinder. They were wasted on that vehicle.
I had a 4.0 in my 02 wj that cracked the skirt off the number four piston at 103,000miles. Lucky I noticed a change in the engine sound and shut her down right away. I ended up rebuilding the engine for about $600 in 2013. Put another 20k on it before I traded it in for a jku in 2015 that I still have. I loved how easy that engine was to work on.
I just bought a 99 Jeep Wrangler with the 4.0. Everyone told me to buy a jeep with that engine in it. Glad i did. They look really easy to work on. hopefully i wont have to for some time.
"Can't start in the back. That's how you get an infection." I laughed WAY too hard on that one!
What video is this referencing? I’m waaayy behind lol.
@@dbsranchr s*x
@@205rider8 oh shit…… I’m such a dumbass 🤣🤣🤣🤣
@@dbsranchr took me a minute... not gonna lie.
Yeah i had to stop, go back and replay ... it's a good thing this channel doesn't have many young viewers "Daddy why do you get an infection if you start in the back"
Just did a 2004 XJ with a 4.0. It had two pistons that dropped their skirts. 279,000 miles. The customer replaced it with a reman. This is a common issue with the High Mileage 4.0s. What happens is as follows. It starts to overheat or run just a bit on the higher side of 220 degrees. The piston skirts crack or break off leading to it burning some oil. The oil soot covers the 02 sensor, and tricks it into thinks it is running rich. So the computer adds timing and lean out the fuel to get it within spec. Only to melt down the already damaged piston, and this is the end result.
So it killed itself essentially
So, technically speaking, the pre-Chrysler style injection might not have made something like this happen?
A coated O2 sensor will produce a lower than normal voltage which makes the vehicle think it's running lean, the computer will add fuel so the vehicle will be running rich, not lean.
Are you outside of the us? I thought the last model year of the Xj Cherokee in North America(except for Mexico) was 2001.
thats good to know..... when it got around 110F in NE montana this summer..... my 97 was running at about 217 (used OBD2 scanner)
which is just a needle over straight up and down
.
she hit 227 pulling up "kittleson hill" on my 100 mile daily commute
.
no noises, oil burning, or death yet..... but i was REALLY worried about it
turned off the AC, ran the heater.......knowing that number 6 was probably WAY over 227.....
.
i love my Heep..... its a POS.... but its got soul
Finally a 4.0 teardown! And my god I've never seen that damage to a 4.0 in my life. I daily a 1995 Jeep Cherokee with 254K on it and it runs pretty nicely.
we have perished already
When I was a teen my mom had an 1987 AMC jeep Cherokee with the 4.0 and it had over 300k on it the trans had been rebuilt but motor was unopened besides remain seal and valve covers along with intake and exhaust manifold being redone. Thing was reliable only issue we ever had with it was a upper radiator hose blowing while we're were on the road used a knife cut the bad section out put water in it till we got home and it was good.
behold, a god that bled
It had to be neglect. I sold my '92 XJ six years ago with 260k miles on the odometer and it still ran like a raped ape.
So, so much like a slant six. Wow
Fun fact. This engine was designed by engineers from all the big three makes. AMC came around and they stuck this in about everything. When AMC disbanded Chrysler kept using the engine. It has one of the longest production life spans of any engine.
It's based on the 258/ 4.2 l, you can use the crank and rods out of that to make a 4.5 l stroker in a 4.0l block
@@BeepBeepParkieMore Fun: the AMC 6 began life as a Nash motor in the late 1940’s. The 7 main bearing bottom end is what gave it legendary durability.
@@BeepBeepParkie, I did not know that. I wondered what the stroker was built out of. Thank you.
American Motors loved this engine!
I owned a 97 Cherokee with the 4.0L. After 212k miles the engine still ran strong. Like you said, everything around the body was falling apart or broken, but the engine always started up.
I had a 1996. Great drivetrain but the rest of the Chrysler stuff will fall apart around it.
I have a 2001 XJ and it has been rattling for eight years, so bad I tell people that it's a Cummins swap. I paid a mechanic to drop the oil pan and take a peek. He couldn't find any loose so he buttoned it up and said to just ignore the rattle and keep driving it. That was eight years ago.
Good chance that rattle is the exhaust manifold. When they crack (and they all crack), it'll rattle like a diesel.
Rocker arms
Flex plate issue. They Crack and starts to tick.
Good to see an uncomplicated old style basic engine that anyone could work on without a shop full of electronic gadgetry and specialist tools..
Not too unlike the old Chevy 232 inline 6. I never liked the timing gears on those, though.
Wish is was still like that.
just rebuilt mine for a second time, got 60,000+ miles out of that and now has just under 350,000 miles. love this motor!!
Got a 2001 Cherokee with 263,000 miles original motor daily driver rig. Impressive to see what abuse these motors can take til they let go.
I bought a 1996 Grand Cherokee with 267,000 miles on it. It was my first Jeep. It had a slight tapping coming from Cylinder #6. Started using T4 10/40 in it and it quieted it substantially. Drove it till about 301,000 miles and then it developed a really loud chatter. Still drove it another 2,000 miles that way till I finally bought another vehicle. I got curious and dropped the oil pan. The piston skirt for cylinder #6 was laying in the pan. Engine still ran and had good compression. Just piston #6 was chattering around in the cylinder.
Had a 99tj with about 90k on it break a skirt on the piston on cyl 6. Thought it was a rod knock at first. Pulled it and tore it down. Found the rod on cyl 4 visually bent as well. Never hydrolocked it. Figured I had it apart so go big or go home. Went .030" over, stroked it with a 4.2L crank, Comp Cams camshaft, bigger injectors amongst exhaust and others. I was very happy with the build!
I've seen that kind of damage in 4.0L in-line 6 before. The 2 main reasons are 1) Prolonged high revving from trying to get unstuck in deep mud, or 2) very steep angles during rock crawling. I have owned many Jeep (Chrysler models) over the last 35+ years. Being involved with off-roading clubs has given me experience with the typical failures for people pushing their vehicles to the failure point.
For a piston skirt failure, that one actually seems pretty tame. Usually the piston comes apart and the wrist pin hammers into the block until it either makes an inspection port or it seizes.
Yeah, that was VERY surprising the wrist pin didn't go sailing and lock the engine up.
"Makes an inspection port" lol that's a hilarious way to look at it.
No it doesn’t
@BB Sky it doesnt, which is exactly the problem. The piston around the wrist pin comes apart, and the rod starts hammering it into the sides of the bore until either the engine gets an inspection port, the rod lets go or the engine seizes.
@BB Sky, pins are pressed in by heating the rod. They can become worn over time and walk themselves out.
I like the 4.0 because of it's AMC lineage. But those cracks in the head you saw are common on certain years, and that's Chrysler's fault, because they redesigned the head. After a couple of years, they saw the common failure pattern, and came out with yet another redesign that fixed the cracking problem.
The 258 cracked heads when overheated.
The most crack-prone heads are just from the start of the distributorless ignition until late 2000. The head casting with the improvement has the letters TUPY cast under the valve cover, but it’s still not quite as good as the 1999 head. IMO, 1999 is the single best year of the 4.0. It has all the strengthening and improvements to the crank and block that Chrysler made over the early kinda flexible AMC design (including the main cap spine),still has the tubular header, has the improved intake manifold, has the best ECM programming, but doesn’t have the issues that came with the head when it was redesigned for the coil rail mounting needed for DIS.
@@stevelacker358 +1 the '99 was the best year with thrust plate cam, horseshoe intake and OG distributor. 96-99 OBD2 is my favorite years.
Too bad these engineers should leave good enough alone
Best part about 97-99 is they don't have any of the advanced emissions Jeep used to try and eek out more lifetime.
Just the one O2 sensor, single bank of six exhaust (which will always crack), distributor, so so so easy to work one.
You can do the entire ignition (plugs, wires, cap, etc) for a third of the cost of coil packs.
Just did a full rebuild on my 2004 WJ 4.0 after It broke a piston skirt. I bought It last July as a winter vehicle and It had a rattle and I couldn't get It to go away. Everyone said It was completely normal for a 4.0 to rattle. I tried everything on the internet to get rid of the rattle, tried using a oil filter that held more oil and still nothing. Noise was always the same but would go away when fully warmed up. But come back on a cold start. It got me through a whole winter of beating on It and was using It as a a backup one summer day and was ok the highway and the rattle turned Into a knock. Drove straight home and parked It. Thought a lifter had gave up and tried thicker oil and even Lucas oil and nothing made the noise get quieter. That's when I knew It was an Internal problem. Started tearing It apart and found cylinder 4 with a broken piston skirt. Did a full rebuild and now you can't even hear that It's running. It's been back together about 5 months and I've made It my daily even before winter started and I do not baby this engine except on maintenance. I did all the piston upgrades, moly pistons, moly rings all new bearings. Hardest part of the whole job was getting the intake and exhaust manifolds off while It was still In the Jeep. When putting It back together, I Installed the manifolds onto the head before I put It back In the Jeep. So much easier, but extremely heavy and would recommend a 2nd person to help lift onto engine.
Had the same 4L in a jeep Wrangler in the shop this past year, thing had completely seized, and when we pulled the pan there was mud in it. When asked, the owner denied having driven it in water or anything. We sent it away for a complete revision along with boring it out into a 4.6L. It now makes 300 hp and 600 Nm of torque.😁 Was quite a fun project. Had to modify and rebuild the entire jeep as it wasnt roadworthy anymore. One hell of a project for me and another mechanic, but a lot of fun
The 4.0 "AMC" and Furrrrd's 4.9 300 straight 6 are both legendary in similar ways. I had a '81 Bronco with the 300 and a manual 3-speed ( with overdrive) that was one of my favorite trucks ever! 300,000 miles on that truck. Too many things went wrong too quickly on the Bronco so I sold it as a parts truck. The 4x4 still got me anywhere I needed to the very end. 🏁
I daily a 1984 F150 with a 300... very durable engine indeed. Rebuilt it back in 2020 due to bad rings/bores (lots of blowby); despite that, it was still running somewhat decently. The rebuild was its reward for getting me though a long trip I didn't expect to drive it on... well earned!
That Ford 4.9 is a great engine.
I've been hounding Eric to get his hands on a 300 for a teardown but they're so fucking reliable that cores never show up haha. I have an 85 and a 95 F150, both with that engine, both with manuals. Love 'em both.
@@TestECull We used to run F-150s with the I6 300. Mostly highway, with some local parts running. Manual transmissions. We never had to replace an engine, and some of them had well over 300,000 miles. They got three times the mileage of the oldest truck we had with a 460 under the hood. That 460 was bomb-proof, too.
@@dougrobinson8602 Best OHV engine Ford ever sold. Pulls like a 302 on a third less gas with a life expectancy measured in decades because odometers dont go high enough 🤣🤘
My brother had one of these in a jeep that had over 200k. It had a cracked radiator so he'd have to refill it. Sometimes he would drive longer than 30 minutes without coolant and the temp pegged on H and when he got home it would be bone dry. Drove like this for a few months. He had it for a year more and sold it to the neighbor who had it for years. Have to work hard to kill a 4.0
I had it in the Jeep Commanche and Cherokee. They had some getup and go in them
I've currently have 4 from 91-05 one of unknown year in my 90XJ it was replaced twice in the past warranty replacement first the second was due to bad replacement oil pump. Solid engines with simple upkeep on oil, coolant and plugs
It's insane what these 4 liters can take
Your brother is an a-hole. Driving a half hour with no coolant, wtf.
Yes, Finally!!! My favorite engine too. In fact, I'm dailying my 04 WJ at the moment because well, it's the only thing I own that doesn't ever break. From what I remember, somewhere around 2000-2002 were the problem years with cylinder heads cracking, at least for the WJ. By around 03 and definitely for all 04's have a different head (denoted by the "TUPY" stamping under the oil fill cap) that isn't prone to cracking. I'm 32 and I expect my 4.0 to outlive me!
So glad to see the 4.0 inline 6. They are so hard to find as cores. One of the best engines ever made.
Would still love to see a GM 3800 series engine on the channel, or a 3.5L V6 from the 93-97 Intrepids/Concords
I second the 3.8. It's one of the most reliable engines ever built if taken care of. Incredible highway mileage as well.
@@dougrobinson8602 Yes, 3.8 or 231.
I’ve had both the 3800 is rock solid the mopar 3.5 at the time had a very weak bottom end and I ended up spinning a bearing
My family had both of those. The 3800 Vortec was BULLET. PROOF. The 3.5 was fine enough, but the transmission that rode behind it was garbage. Lost reverse out of it at 36k miles.
@@dougrobinson8602 the Achilles heel on the later 3800 engines was the plastic intake plenum, which was notorious for getting brittle and cracking, which would dump coolant into the engine. If you buy any car with one of those engines, make sure you replace that part right away.
I've got a 1946 cj2a and it's still running the original 4cylinder GoDevil engine. Built to last!
Can't remember the year for the water pump change , but if memory serves me when jeep went to serpentine belt the water pump went reverse rotation but the old pump will still fit . May be part of the problem , wrong rotation will still move some water but not enough .........
Sold mine after 350,000 miles and it still ran great. It was the family adventure vehicle. Heavy loads and back country roads were no problem for our 1995 sport. It did have a cracked exhaust and after my son used it two of the engine mount studs were cracked. I welded the engine mount back to the studs and it was good to go.
Greatest engine AMC produced (RIP) and one of the greatest engines of all time.
Thank you! Another one off the list!
This engine is, of course, one of the most durable and torquiest motors available from the late seventies through the early aughts. The inherent primary and secondary balance of the straight six aside, just the combination of torque, ease of maintenance, and simplicity all made it the absolute pinnacle of the Wrangler powerhouse. This engine is still the best 6 cylinder that has ever been in a Chrysler product (slant six aside), and I have a couple customers that have their Grand Cherokees and wranglers up past 300K. Having to drop the 242 and the 318 from their lineup has left FCA continuing to fight for a 6 or 8 cylinder gas engine of any sort of quality, a fight that to this day has not been won. Yes, I know what I said. The Gen 3 hemi is barely worth its weight as a boat anchor.
Of course you're not going to have a problem with the dipstick tube - it's not on a GM product.
Engine Requests:
Ford: 300 Inline Six, Windsor, FE, 1.0 EcoBoost, 1.4 EcoBoost, 5.2 Voodoo, 6.7 PowerStroke
General Motors: 3100/3400/3800 Olds, LUW/LWE 1.8l i4, L5P Duramax
Chrysler: Slant Six, MORE HEMIS, 1.4L FIRE, 3.3/3.8, 318/360
Honda: B Series, D Series, K Series
Toyota: 1GZ-FE, 1ZZ or 2ZZ
Subaru: FJ series, EZ30/36
Other: DT466
Old School Unicorns: GM 702 Twin-Six, Oldsmobile 5.7 Diesel, LT5 Lotus (C4 ZR1)
Modern Unicorns: Toyota 1LR-GUE, Chevrolet Gemini, 7.3 Godzilla
Well now we know.
@@chuckz8053 And knowing is half the battle. The other half? Extreme violence.
He has an EZ36 on the shelf/rack to his left our right when he shows the other 4.0 on the ground. I know it's a 36 because the intake runners are huge. I doubt he will take it apart but it'd be nice. Those EZ are not easy to disassemble. Even worse to get together.
Honda F20/22. I wanna see how those 9000 rpm motors tick. :)
And Olds 5.7 diesel would be cool to see, but they're rare. An LT5 is rarer yet. That was the best DOHC GM ever built and how they got the Northstar from it is beyond me.
The later 4.0L engine built between 1999 and about 2002 used a head casting #0331 and was prone to cracking between the 3rd and 4th cylinder due to the exhaust port redesign to meet emissions. This same head casting #0331 was redesigned and they added a TUPY casting mark on the surface of the head just under the oil fill cap. The head with the TUPY marking was corrected to prevent this cracking. The #7120 casting between about 1996 and 1999 I believe is the best for performance as it was less restricted before the emissions redesign.
I really appreciate how you speed through repeated bolt removal once the initial fastener is dealt with like on heads and rockers. Very enjoyable and informative stuff!
one spark plug that's all you really need is one cylinder to fire for the engine to run🤣
When you rotated the engine and all of the tappets fell out it brought back fond memories of my 83 CJ7 and it’s lifter problems. Still runs great today.
The cylinder head definitely feels like 89 lbs when you are leaning over the front of the jeep or the fender to remove it and even more when you are putting it back on
There was a little known issue with water pumps. The inline sixes had 2 water pumps. V grove turned one way. Serpentine turned opposite. They could easily be switched and the coolant would not circulate properly causing meltdown of the center two pistons.
Love my 95' 4.0! It's just broken in at 205k miles. I replaced the water pump and thermostat on my own. Pretty easy to work on
There is a clear crack in the cylinder head, between #2 and #3 rocker arms. It can be seen just by removing the oil fill cap and looking in the valve cover. I was a jeep tech in the early 00s, this was very common on 98-03 cylinder heads. I replaced hundreds under warranty.
I think my 99 came with the 30 year/300k mile warranty! Knock on wood it seems to be going well so far. Coming up on 274k
Had a 95 GC with the 4.0 with 325k when I sold it. Only problem I ever had with was the water pumps shreading every 20-30k miles. I got very good at that routine maintenace.
Just replaced a 02 with 112000 miles for the same thing customer thought he had a lifter problem engine ticked. Dropped the pan and no skirt on # 3 and 5 pistons common problem. jeep dealer told owner you have a 50/50 chance you got one with defective pistons! Engine was spotless inside well maintained as clean on top as on the underside.
One time I pulled apart a 4.0 from like a '92 Comanche and it had been run at least 60 miles distance with pieces of a broken valve riding bouncing around inside a cylinder. Top of the piston all scarred up and walls not perfect. I ground the top of the piston with a dremel tool, threw on the rebuilt cyl head, and it ran perfect for over 10K miles until I sold her.
A mechanic friend told me a story about one of his customers that had towed a Cherokee using a front axle type dolly for about 50 miles and then remembered that he had forgot to take the trans out of low gear and then found the engine wouldn't start. He pulled the head and ALL pistons were missing- just con rods and wrist pins were left...
Calling BS on that story. If it was an automatic, the engine wouldn't turn. If it was a manual, he'd been dragging the wheels.
@@spasticslug2932 Yeah, you’d ruin the transmission and that’s about it. The only possible way that story would hold water was if it was a straight shift left in 5th gear, and even then it’s not gonna do what he said it would, especially just after 50 miles.
BS… unless it had no serpentine belt on, if the crank was turning the water pump would be turning, if the engine got warm enough the thermostat would open and the radiator would cool the engine just the same as if it was running.
But more than likely it would just drag the rear wheels…
it happened, I know the mechanic that replaced the engine.
I've repaired quite a few of those with piston skirt failure. Overheating doesn't help things either. They start making a thunking noise like tapping on a tin can at idle when they start failing. Those can be repaired with a set of pistons and rings. I always opted to do the timing chain and bearings. They literally run for ever if you catch it early. The last one I did was a 2001. Thanks!
I have a 2001 Cherokee that used to be a cop car until 100,000 miles. I bought it at 130,000 and by 135,000 the engine had no power at all. Wouldn’t even climb hills. Took it to a shop and they said it was a miracle it even made it there. It was just a worn out girl that needed replaced.
My son bought a 2004 Grand Cherokee with the 4.0 and drove the hang out of it. I got it and drove the hang out of it then gave it back to my son, and he drove the hang out of it then gave it to his father-in-law, and now he's driving the hang out of it. The computer is starting to go away, but the engine's been solid.
Those are known for pcm rot.
I’m a technician and to be honest I’ve had nothing but bad luck with the Chrysler 4.0. Sad by true. Always overheated or head warped it’s always a bad egg. Piston slap as well.
Don't trash that block! It may be suitable for an overbore as long as there are no cracks in it. Someone might be interested in buying it for a stoker build.
Finally! I'm glad you finally made a video on this engine. The 4.0L is the only good thing about my jeep and it still isn't perfect. I just read the description and my uncle has a 2004 WJ grand cherokee with over 350k miles it takes literally a minute of cranking but it still starts and runs
That block would be good for a over bore and then a stroker setup.
Waste of time
I SAW A CRACK on the deck of the block
All that for max 200hp
@@alexstromberg7696 add boost!
@@alexstromberg7696 Ummm no. It makes about 200hp stock and stokers can make 300+ hp.
Why do some people always feel the need to comment on things they know literally nothing about?
My 4.0 in a 2004 Jeep Grand Cherokee with 120,000 miles with oil changes every 3000 miles started making noise. I drove it to an engine shop 40 miles away. They dropped the oil pan and it was full of piston parts. The shop didn't know how I was able to drive it 40 miles. I had them put in a new crate engine, replace the water pump, radiator, hoses, etc. I have around 250,000 on it now and just finished up replacing all my suspension parts in my garage. (Glad I don't live in the rust belt!)
That version of the 4.0L was used in the 2000-2006 jeep wrangler, and the 1999-2004 grand cherokee, I can tell by looking at the water pump and the accessory drive
I have a 2006 Golden Eagle 4.0, C.J. auto trans, a/c just turned 60,000 miles, still runs like new. I'm a service nut and stay up on servicing it. Changed the water pump and thermostat and hoses at 50,000 mi just because of age...Love that Jeep!
Can you imagine going in for a physical exam and your doctor making the same noises as Eric does when he examines this engine block?!?! (Hmmm....maybe it wouldn't be that funny after all. 😱)
I got flashbacks from a dentist visit watching that.
What your doc don’t?
🤣🤣🤣!!!
I can't imagine going to the proctologist and him making an ATM joke like he did.
I was just thinking of a surgeon musing to himself "Hmmmm-hmmmm. Looks good. That's good. Oh, *that's* not supposed to be there!"
Actually, considering the context (that 4.0 was very thoroughly deceased) probably an ME.
Got a 97 with an old trw 5.0l stroker kit and a hesco aluminum head. Threw on an m90 blower and a pacesetter header blowing through a dual 2 3/4 exhaust. Sounds awesome and just will not die!
UK mechanic here, I absolutely love the channel, I'm addicted. You do a lot of complicated big blocks I would love if you could do some small European engines like some small inline 4 cylinders as that's mainly what we drive over here and their an absolute breeze to teardown and rebuild 😊
Thanks for the entertainment over the year. Have a beer on me, happy Christmas to you and your family.
love the Jeep 4.0 and the Ford 300 6 cylinder engines
Since the cylinder head cracks line up with the most damaged pistons, I'll guess coolant was getting into those cylinders causing detonation, which leads to the torched pistons. I'm impressed the pistons didn't come apart with how loose they were on the wrist pins!
l would agree with your thoughts on the damage cause
Thats the beauty of momentum. It broke just right.
Bet the engine still ran too
13 years as a flat-rate mechanic, owned 7 XJs (have one with nearly 300k miles), and I have NEVER seen this level of damage to a 4.0l.
I'm a retired mechanic of over 30yrs. and current 4.0L owner and I've replaced over a dozen exploded 4.0L in my career. Leave them stock and drive them gently or they Will break. That's the advise I've learned to give.
@@RANDOMNATION907, huh, driven the hell out of my current XJ with a 4.0l, and it's at 280k miles without a single issue. Where the 4.0l runs into issues are the late 1996-2006 (2001 for the XJ). These engines have some know issues with severe overheating from a flawed head design and piston skirt failures causing engine failure.
Seems to be that the early 4.0s are stronger then the later ones idk why or how , own and owned alot seem damage at later model ones
@@JohnGarcia-ii8lb, 1997-2004 (last year of the 4.0l) is known to have weaker piston skirts... even then, I haven't seen one experience this level of destruction.
@@johndeeregreen4592how good are the 2.5?
31:54 When I did a head gasket job on my 85 F150 many moons ago I didn't even ATTEMPT to manually lift the head. I got the cherry picker in there to lift it out, and it lowered it back in with the cherry picker. There is ZERO chance I will ever be able to get that three foot long lump of cast iron off the block, over the fender/core support, and onto a work table without throwing my back out.....
Those Valvoline oil filters don't have a bypass valve, seen them plug up and cause codes or destroy engines several times
My daily driver is a 94 cherokee with a fresh 4.0. The issue I have was a used torque converter that leaks at the seal, as a very slight wear groove and where I installed a sleeve as round two. And where a driveway leak is problematic and waiting for a full trans refit. As for the rest of the body, I really like the simple, long lasting functionality. Very solid . Thanks for the full view to engine. M.
You magnificent madman, you finally got one for us! I've owned many Jeeps with the 4.0, XJs and ZJs both, so this is going to be fun. Besides piston skirts and the TUPY heads, these were solid. Although the cooling system was rather inadequate in the XJ, application. You have to ON TOP of cooling system maintenance on those. ZJs were a clean sheet design, so the 4.0 was integrated correctly in those from the get go.
What causes the Piston skirts to break on these?
I've seen it a lot but I've never been able to understand what really causes it 🤔🤔
My 02 wj never gets hot, has 220k on it and I drive it up north n back 400 miles both ways in extreme heat and stop and go interstate congestion. Never runs hot, always on top of oil changes I do myself with pennzoil and Fram filters everyone hates for some reason. I've ran Fram my whole life never had an issue, I also use Lucas oil treatment.
I've found on my XJ, that you just replace the entire cooling system every 4-5 years.
There's two Achilles Heels:
1) the viscous fan clutch wears out
2) the radiator fills up with sediment.
As long as you shotgun the whole thing, and give it a good flush, it's really no problem.
@@lustfulvengance I don't have a specific answer, but most people agree it's a materials/design issue (dimensions of the skirt). It also affected the 4.2 inline 6, the 4.0s predecessor. My understanding is that it officially only affected about 6% of all units, although reality could be different. When you consider literally millions of these were produced, 6% or more is a decent figure.
@@litz13 I think the sediment thing is due to mixing coolant. I've had it in my XJ, but since the last time I replaced the radiator and gave the whole system a good flushing I've stuck with plain, old fashioned green coolant and stayed away from the universal stuff. My 4.0 runs nice and cool, even in the summer with the AC on.
04:38 "This water pump looks like new and would be a good backup" then sounds of the water pump being tossed unceremoniously across the room. This is why I love this channel.
Since that engine development was started in 1956 by Nash, then it was made by Hudson, then made by Rambler, then made AMC, then made by Chrysler for Jeep…
After 50+ years, they better have figured out how to make it work right!
The 4.0 actually was based on the 232 first put in 1965 model year AMC’s, and shares nothing with the earlier 6 cylinder engine.
@@nuttfarmgarage6434 Just to pick a nit, according to Wiki the new 232 was introduced in May of 1964.
@@JeffDeWitt What part of 1965 model year do you not understand?
@@nuttfarmgarage6434 the early engine was changed repeatedly to make improvements. Just 'cause new parts don't fit old junk doesn't mean the whole thing is different. One step leads to the next, and you can't get to the top without climbing the steps.
@@brandonupchurch7628 Last I looked 1964 was before 1965. The 232 was introduced in the special edition 1964 Rambler Typhoon. The article in Wiki even has a picture of the car and the license plate says "1964".
I had a guy drive his wifes 99 jeep Cherokee 25 miles into the shop the 4.0 ran decent but had a miss never made any noise but when we pulled the head off #6 piston was gone!! didn't scar up the cylinder at all we dingle berried the thing put a new piston and wrist pin on the rod reused the rod bearing because it still looked great and she's still driving it today 3 years later. The head casting on these are junk. But with much needed radiator upgrades these will last for a long time. AND A 180 DEGREE THERMOSTAT IS A MUST!!!
Yes finally. I’ve been wanting to see one of these bad boys for a while
👍 thanks for making me feel better about my 4.0 with 319k miles on it! It's had a oil leak on the last 2 cylinders coming out the head gasket for about 60k miles. It's always been on my "I'll get around to it..." list.
My brother had a box style Cherokee, with the high output, I think they called it, it had over 300,000 and ran like new! You couldn't kill it, he traded it in on a new car.
I had a piston melt through on my 5.0L Ford V8. Heard the sound of (what I now associate with) pinging when under load and it finally let go while towing a load of hay for a friend. Had to drive it another 25 miles before getting it home, blowing smoke the whole way. Looked exactly like the one you pulled out of this 4.0L.
The fix was an in-frame piston replacement, complete with a stone hone to knock off the extra aluminum spray and somehow a much thicker wrist pin than what's on the rest of the rods. So it's got a tiny shake at idle but still runs strong!
Eric, when you disappeared off screen pulling the cam, I expected you to edit it to look like the cam kept going on forever, you know how a magician pulls the endless handkerchief out of his hand,
It was fun to watch, just kept coming out.
We're just so used to seeing only 4 cylinders with worth of cam emerge from the engine.
Definitely not replacing one with the motor still in the body, without removing a whole lotta' stuff first....
6:19 If they don't crack, they warp. The Ford 300 does the same thing for the same reason. My 85 F150 will have an exhaust leak for as long as it retains the factory exhaust log because it's so badly warped #1 exhaust port will never even attempt to seal. It's a good thing I don't really care about exhaust leaks haha
Eric, Merry Christmas to you and your family. Thanks for taking us along with you this past year. I’ve enjoyed your videos, your humor and presentation style!
I had a 91 Jeep Cherokee years ago from new. Developed a ticking noise under warranty. They replaced the top end and noise didn’t go away so they replaced the short block. Lasted me almost 400,000 kms before developing a tick so I sold it. Excellent vehicle and easy to work on 😊
That was some impressive damage! Great video as usual. There’s a couple 4.0’s in my driveway.
I 100% agree with the early exhaust manifolds. I would be replacing at least one a week at the Midas shop I worked at. The replacement ones had a small flex section on the number 1 and 6 pipe to prevent a recurrence.
I'm convinced that inline engines are better than V4 or V6s. Just my opinion.
Smoother and more reliable fs
My 96' grand Cherokee has a V8 5.2L (318). Been awesome rig. The motor was replaced back in 2014 by previous owner, with an '03 dodge dakota motor, bolted right up along with all accoutraments. Jeep is still pretty much stock but is a great driver, all I'vehad to do to itis tires, a few sensors, new alternator. Great vid Eric!!
Your videos keep getting better and better! I love watching you channel, its relaxing and entertaining. Always looking forward to seeing your new tear-downs and project updates. Your commentary is my favorite part lol. Merry Christmas man!
With a flat tappet engine, you can check lifters for wear by placing "flat" ends together and see if they rock slightly. Ends are groundspherical when new.
After just tearing a toilet apart going spelunking for my headphones, I needed to see someone else tear something else down and get gross.
@Lil Smoot I have never heard that word in my life and I am not sheltered grammar wise. Learn something new every day lol
I think 🤔... I think 🤔 I'd just have bought a new pair and flushed them 😂
@@ianriggs isn't spelunking just another word for cave exploration
Hahahahaha!!!!
I agree just flush and get new ones
I have an 00 XJ, the story was it got hot and he parked it, i pulled the head off and the head gasket was blown between cylinders 2, 3, 4, 5, and 6, #5 has rod knock and #4 piston welded part of itself to the wall, amazingly the thing still ran before I pulled the head. I put an mls head gasket and a spare 0663 head I had, still in the process of finishing up. XJ's are one of my favorite vehicles along with GMT800's and W-bodies.
Merry Christmas and a Happy New Year! Thanks for all the humor and jokes throughout all these tear downs and projects! You are like an auto coroner on the channel, but you also save a lot of cars from the salvage yards. You should be called the car doctor for all the autopsies and projects. Keep up the great work!
this just goes to show you can even destroy a spicy 4.0 engine if you try hard enough🤣
They are tall, and I guess it's easy to build up air pockets in the top cooling passages of the head. My kid destroyed one driving with low coolant, but a head plane and valve job fixed it. Did new lifters at the same time, and used my old Ford trick of grinding off any wear bumps on rocket arms that might restrict their range, and hand fitting washers under the rockers to compensate for wear and the milled head.
I look forward to Saturday evening so I can see what you're going to tear down! Thank you from an armchair mechanic!
Love this guy! No bs, no flash. just great info. I'm running a 98 ZJ Grand Cherokee Laredo 157K just fought the death wobbles. think I might have got it, finally. KOW
Please find a blown up 3800 series pre 2004. I want to see how someone can kill a very reliable engine
I 2nd that and I'm curious too.
.....supercharged!
Thank you for the video. I have owned two jeeps now. Both have run hot and burst the radiator. The first a 2000, also spun a bearing and started knockings. (like the motor you showed).The second is a 2004. It ran hot while idling in my driveway. It also burst the radiator. This time I don't think it hurt anything as far as I can tell. But I had enough of the electric fans. I went to a junkyard and pulled the the manual fan off an older jeep and replaced the electric fan. Bing,bang,boom no more problems. I have 134,000 miles now and it runs like new.
P.S. I think someone had tried to rebuild the bearing in that motor after it had run hot.
Which is more ... bulletproof, in your opinion. 4.0 L Jeep or 225 CI Slant Six ? Have you torn one of these down. I had one (moons ago) which continuously had 'grey' oil and a leakiny rear main (fill the oil, check the gas). TBH, the oil leak kept the body of the D-150 (A833) frame from rusting. The carbon (1bbl) kept the exhaust from rusting.
My friend had a slat six in his old Dodge dart Swinger. We actually tried to kill it with a brick on the accelerator pedal. It revved up and would not quit. Valve float kept it from revving too high, and we finished off a six pack waiting. Never died.
I vote for slant 6
We all have cars we never should of sold, for me my f250 and bronco, miss them so much 😢
I am doing a 4.0L rebuild now and the block was in worse shape. That block you have is the perfect candidate for a stroker build, if a .060 Overbore is possible. Mine had lips on all six cylinders where the rings had really dug into wall, like I caught my thumbnail on the lip. That's likely why your pistons 3 and 4 refused to come out, they were catching on a lip. Part of the reason why Cylinders 3 and 4 on the I6 (of any Generation, even on the Rambler) fail is because their exhaust ports are right next to each other and they build up a ton of heat in that region. All AMC style I6 heads can fail here, just on the new head from 2001 on, Chrysler was counting beans.
My core was only $100...then I spent $600 at the machine shop getting the cylinders bored and block fluxed.
Had 93 grand Cherokee. Motor was bout shot, so I bought a White Brothers 4.6L kit for it, that thing was a beast! That motor your dismantling is roasted, mistreated bad.. great vid man. Commentary is priceless!!!! Great vids Eric!!
5:39 It looks like it wouldn't be overly difficult to bolt a carb onto that intake manifold....
ITB EFI?
Man you brought me back to the 90's! I was one of the Senior Technicians on this engine at Chrysler Jeep Truck Engineering in Detroit. The 4.0L engines commonly ran 2 to 3 times longer than the target of 1000 hours on durability test.
Wouldn't mind seeing what the burned Vette engine looked like up close. Even if you don't wind up tearing it down.
That is the longest engine I have ever seen! It looks overbuilt, like it belongs in a tractor. The AMC 242ci I6 engine had amazing durability until 2000 when the cylinder head was made too thin. From 2000 to early 2001, cylinder heads were cracking between the #3 and #4 cylinder. However, the cylinder heads marked with, "TUPY," were much thicker than the problematic 0331 cylinder head. It is likely this engine has the problematic 0331 cylinder head.
First 2 causes that jump to the top of the list:
1. Hydrolocking
2. Overheating
Clearly it was over heated. Bad 🔥
Thank you for doing the 4.0L ... I have an 80 CJ with the 258. Never seen a melted piston like that in a Jeep I6!
In the old days people used to shut of their engines when they got hot . nowadays they just keep driving till they, can"t .
i have a WJ with the 4.7, honestly kinda happy i dont have the 4.0
yes, its not as bullet proof but its been great. ive even been on lakebeds that have hit 118, and stopped on. freeway when its 124. no heating issues or anyrhing. and its been great. tows good too
I worked as a forester for a large private landowner. I always drove 4X4 Fords, but when it needed maintenance, I would have to drive a Jeep CJ with a straight six. The vehicle was miserable to drive. Cold and wet in the Winter and hot in the Summer. Now, I'm no Jeep expert, but I had a couple of buddies that had CJ's with V8's, one with a 390 AMC and the other had a 343( I think ).They were both better in the mud and logging roads that I traveled daily than the 6 cylinder. The company put some bigger, more aggressive mud tire on the Jeep with a 6 cylinder. They were wasted on that vehicle.
The exhaust manifold isn't difficult unless you own a Cherokee lmao 🤣 that was probably the most time consuming repair i've had to do to mine lol
I had a 4.0 in my 02 wj that cracked the skirt off the number four piston at 103,000miles. Lucky I noticed a change in the engine sound and shut her down right away. I ended up rebuilding the engine for about $600 in 2013. Put another 20k on it before I traded it in for a jku in 2015 that I still have. I loved how easy that engine was to work on.
That dipstick removal really makes this engine a contender for the GOAT
I had a mid 80's 2 door 4X4 Cherokee with the 4.0 and a five speed manual. Sold it with 250+K miles. Really a good little truck.
I was waiting for a jump scare looking in those manifold openings
I just bought a 99 Jeep Wrangler with the 4.0. Everyone told me to buy a jeep with that engine in it. Glad i did. They look really easy to work on. hopefully i wont have to for some time.