the problem with the 4.0 is people seem to think that bullet proof also means maintenance free. no one explains that by the time a 4.0 or aw4 finally fails, it already out lasted almost any other at least 3 or 4 times over
My jeep xj 4.0 has 401,425 miles still going! It has been maintained well but not perfectly. timing chain replaced at 230,000 will front seals and water pump. many parts have been change to keep running! when I viewed cycinder walls still had x hone makes! I use rotella diesel oil in my jeep!
I bought one with a blown motor. It's almost done but Yes I put a new 4.0 back in it as 3,000 lb jeeps don't have to be over powered. Just need torque.
Got a 98 XJ 333,000 + miles on her. No smoke, or engine light. I keep her oil changed and coolant flush every other year. (I put a lower temp thermostat in to make it take in coolant sooner to help prevent from overheating although I didn't have the issue proir)
That makes no sense. If overheating is bad, not overheating has got to be more beneficial. It's been over 100,000 miles since I replaced the thermostat and no problems. Even in 100° /99% humidity crawling on trails and its never gone over 200° on the temperature gauge.
@prestondallas4035 the data is out there. 195-210 causes the least amount of wear. It increases a bit down to 180 and once you start getting under 180 it goes up a lot. There's a good graph from Continental engines. The folks who make tank and aircraft engines that visualizes the curve you can find via Google. Along with more discussion on the subject.
@jeepinbanditrider That's due to the engine oil viscosity. However, jeeps run HOT and are prone to overheating. Therefore, depending on how efficient the engine is and in what environment you daily drive, a low temp coolant sensor is more beneficial. Like my 30 year old jeep that's in 1 hr+ congested traffic in Southern Commiefornia. 195 to 220 is where you want to be.
I have a 91 Jeep Cherokee 4.0 high output. 325000 miles. Engine good rear seal leaks. Same transmission never changed. Had a problem with some sensors. All are junk.It’s hit and miss with them. Plus the radiator is weak spot. Just get a two or three row radiator.
...just switched over to Rotella oil ( mainly because you recommended it ) in my xj's...bone stock daily drivers. . . we'll see how this works. Thanks for your videos.
I own two 4.0's. 99 and 01. Love those ol motors. I need a 4.2 head for my 99 4.0. Want to build the 4.6 stroker with supercharger. Can you say "fun"?😅
I'm planning on replacing all kinds of internal parts in the engine of my 91 XJ except for the crankshaft and bearings for it, connecting rods (only bearings and pistons with rings), camshaft and its bearings but everything else is gonna get replaced since I don't wanna take it out overlanding and it fails on me while I'm there. Idk how many miles it has since when I bought it a year ago and I placed it on the side of the house until I had the money to buy all the parts for it. So tomorrow 11/21/23, I'm gonna take it apart. Hope everything goes good.
well - my 1998 4.0 engine has piston slap, possibly skirt, now with 190k - I always took care of her with fresh oil and decent driving - "bullet proof " ?
How do you fix the TPS MAP sensor(high or low voltage) on an xj 93? Both sensors replaced, code 24. High rpm’s before shifting. The code only turns on after the Jeep has been running for a 10 miles or so.
Hey Ronnie, I just bought a xj with a brand new 4.5" RC lift, the axle is rotated slightly forward, do I need to get adjustable upper or lower control arms to rotate it back the 5-6*? The ones I see on freedoms site says from 0-8" of lift, will they work
People don’t understand that these engines especially in Cherokees are a minimum 22 years old. The electronics on any vehicle will go bad. There’s only like 5 sensors on the whole engine it’s not that hard to make them run well.
I thought it was the limited power through the no flow head that makes them live long lives . Jk. Maintenance, watch that oil pressure and temp gauge , and a seafoam service every 20k. It'll last if you treat it right.
@@kevinschmidt9295 my 2001xj has an aluminum head. My buddies grand cherokee and wrangler have aluminum heads. My 98xj that I daily has an iron head. Where did the aluminum heads come from?? They're all stock
I believe the 2000-2001 Cherokees did have aluminum heads, which is also why the models made in 2000/2001 have a an increased chance of head cracking issues.@@kevinschmidt9295
@rexracer7192 your 01 XJ does not have an aluminum head unless someone put it on aftermarket. There were no factory aluminum 4.0L cylinder heads. Now the 4.7 V8s in the Grand Cherokees did have aluminum heads.
You can't make things idiot proof cause idiots are way to creative. But idiots aside, the 4.0 is a great engine. The 4.0 has 7 main bearings, which makes the bottom end very tough. The whole engine is a low-stress motor. If one takes care of it, they run and run and run. If they had a 4000rpm rev limiter they would literally run forever.
the problem with the 4.0 is people seem to think that bullet proof also means maintenance free.
no one explains that by the time a 4.0 or aw4 finally fails, it already out lasted almost any other at least 3 or 4 times over
My jeep xj 4.0 has 401,425 miles still going! It has been maintained well but not perfectly. timing chain replaced at 230,000 will front seals and water pump. many parts have been change to keep running! when I viewed cycinder walls still had x hone makes! I use rotella diesel oil in my jeep!
I bought one with a blown motor. It's almost done but Yes I put a new 4.0 back in it as 3,000 lb jeeps don't have to be over powered. Just need torque.
Got a 98 XJ 333,000 + miles on her. No smoke, or engine light. I keep her oil changed and coolant flush every other year. (I put a lower temp thermostat in to make it take in coolant sooner to help prevent from overheating although I didn't have the issue proir)
Lower temp thermostats are counterproductive when it comes to engine wear. Running cooler causes accelerated engine wear.
That makes no sense. If overheating is bad, not overheating has got to be more beneficial. It's been over 100,000 miles since I replaced the thermostat and no problems. Even in 100° /99% humidity crawling on trails and its never gone over 200° on the temperature gauge.
@prestondallas4035 the data is out there. 195-210 causes the least amount of wear. It increases a bit down to 180 and once you start getting under 180 it goes up a lot.
There's a good graph from Continental engines. The folks who make tank and aircraft engines that visualizes the curve you can find via Google. Along with more discussion on the subject.
@jeepinbanditrider That's due to the engine oil viscosity. However, jeeps run HOT and are prone to overheating. Therefore, depending on how efficient the engine is and in what environment you daily drive, a low temp coolant sensor is more beneficial. Like my 30 year old jeep that's in 1 hr+ congested traffic in Southern Commiefornia. 195 to 220 is where you want to be.
@@TechieTardi have a 97 Cherokee 5 speed stock, what temperature thermostat should i run?
Big fan keep up the good work
245k miles. Changed head gasket once. Runs like a champ.
I have a 91 Jeep Cherokee 4.0 high output. 325000 miles. Engine good rear seal leaks. Same transmission never changed. Had a problem with some sensors. All are junk.It’s hit and miss with them. Plus the radiator is weak spot. Just get a two or three row radiator.
I've got 2 JEEPs with 4.0, a 2000 TJ SPORT with 190k on it and a 1996 XJ SPORT with 388k on it. Both are great and I use them daily here in Wyoming.
...just switched over to Rotella oil ( mainly because you recommended it ) in my xj's...bone stock daily drivers. . . we'll see how this works. Thanks for your videos.
Excellent Sir
Maintenance is standard ON EVERY SINGLE MACHINE, automobiles included
Estoy totalmente de acuerdo contigo. Tengo un xj con 32 años y todos los dias voy al trabajo. Y no le e hecho el motor aun. Gracias
I own two 4.0's. 99 and 01. Love those ol motors. I need a 4.2 head for my 99 4.0. Want to build the 4.6 stroker with supercharger. Can you say "fun"?😅
I'm planning on replacing all kinds of internal parts in the engine of my 91 XJ except for the crankshaft and bearings for it, connecting rods (only bearings and pistons with rings), camshaft and its bearings but everything else is gonna get replaced since I don't wanna take it out overlanding and it fails on me while I'm there. Idk how many miles it has since when I bought it a year ago and I placed it on the side of the house until I had the money to buy all the parts for it. So tomorrow 11/21/23, I'm gonna take it apart. Hope everything goes good.
I have an 03 tj with a 4.0, blew a headgasket as soon as the water temp hit 220° at 150k miles.
well - my 1998 4.0 engine has piston slap, possibly skirt, now with 190k - I always took care of her with fresh oil and decent driving - "bullet proof " ?
Great video. In your opinion where is the most common oil leak found. I’m thinking rear main seal but was wondering if you agreed. Thanks
Yeah most definitely is the rear main seal and oil filter housing
I have two XJ a 1988 and 1999 from my experience they leak from rear main seal, valve cover gasket, oil pan gasket.
How do you fix the TPS MAP sensor(high or low voltage) on an xj 93?
Both sensors replaced, code 24. High rpm’s before shifting. The code only turns on after the Jeep has been running for a 10 miles or so.
Hey Ronnie, I just bought a xj with a brand new 4.5" RC lift, the axle is rotated slightly forward, do I need to get adjustable upper or lower control arms to rotate it back the 5-6*? The ones I see on freedoms site says from 0-8" of lift, will they work
I would try the top first but make sure your caster is in spec after your done they should if the are adjustable
The 0331 cast makes it so reliable 😂
It’s hit or miss with the late models 0331
People don’t understand that these engines especially in Cherokees are a minimum 22 years old. The electronics on any vehicle will go bad. There’s only like 5 sensors on the whole engine it’s not that hard to make them run well.
Cool 😎
I thought it was the limited power through the no flow head that makes them live long lives . Jk. Maintenance, watch that oil pressure and temp gauge , and a seafoam service every 20k. It'll last if you treat it right.
I've seen nothing but good things from the 3.6 that are maintained properly.
Just stay away from the later 4.0 with the aluminum head, Iron head 4.0 for the win.
they never made a factory aluminum head
@@kevinschmidt9295 my 2001xj has an aluminum head. My buddies grand cherokee and wrangler have aluminum heads. My 98xj that I daily has an iron head. Where did the aluminum heads come from?? They're all stock
I believe the 2000-2001 Cherokees did have aluminum heads, which is also why the models made in 2000/2001 have a an increased chance of head cracking issues.@@kevinschmidt9295
@rexracer7192 your 01 XJ does not have an aluminum head unless someone put it on aftermarket.
There were no factory aluminum 4.0L cylinder heads.
Now the 4.7 V8s in the Grand Cherokees did have aluminum heads.
They never came with aluminum heads?
The audio is not so good
You can't make things idiot proof cause idiots are way to creative. But idiots aside, the 4.0 is a great engine. The 4.0 has 7 main bearings, which makes the bottom end very tough. The whole engine is a low-stress motor. If one takes care of it, they run and run and run.
If they had a 4000rpm rev limiter they would literally run forever.