Fan Clutch Explo-tionation
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- เผยแพร่เมื่อ 14 มิ.ย. 2014
- This is an exploded diagram in the physical form with an explanation of how a fan clutch works. I also heat the bimetal spring to show how that works. For another video on how the viscous fluid design works you can click here → • Viscous Fan Drives
If you want to see what tool I used to cut this on Amazon you can click here → www.amazon.com/gp/product/B001...
The disc I used here on Amazon as well → www.amazon.com/gp/product/B000... - ยานยนต์และพาหนะ
Awesome video! Probably the best explanation anyone could possibly do on a fan clutch. Thank you for taking the time to make this video.
Thanks! Glad you liked it!
Thanks for this post. Great explanation. I had no idea how they worked or really the complete function until watching your video.
Thank you for the explanation how the fan clutch works, I was wanting to know how it did!
I've been reaching for 35 years that's the best explanation I've ever f****** heard or seen of could work
Great dissection of a mechanical fan clutch. Learned a lot.
My Jeep didn't come with the factory tow package. It has an electric fan for the radiator, but I need to add the mechanical fan with a clutch to add extra cooling. Thanks for the explanation. I had no idea how it worked. Great videos.
Nice video happy belated father's day to you too
Happy Father's Day! Great video!
Thank you for the video brian
@briansmobile1 the fan hub you cut up should have had silicone oil in it, if it's empty, that's why there's no resistance in it and it doesn't work.
If you open the new one, it will have around 30-60ml of honey consistency silicone oil in. Different hubs and engines require a different oil weight, i Just put 36ml of 10,000mm2/s in my hub.
Excellent video and explanation but it's missing a vital part!
Cheers!
Hey Brian, this was such a cool video!
Happy Fathers Day
Looking forward to watching your other channel
Aloha and take care
THANK YOU it has been killing me wondring how those work for a while now
Very cool Brian! I was actually quite interested in how these worked, wanted to try to add an override switch to them but looks a little impossible. Either way you make really great and informative videos! Keep it up. Btw, You remind me ALOT of my oldest brother.
Love the videos happy fathers day!
Great video. My Jeep is having an issue with the clutch fan I believe. Keeps nice and cool on the highway, and on long straightaways...then in traffic it runs a bit hotter without overheating. I didn't realize that the spring in the middle was a sort of 'thermostat". I figured they just ran on centrifugal rotation based on engine rpm.
Nice tear down.
Hey Brian- this is a great video explo-tionation! I am about to buy a 7 blade Mopar fan with a clutch. This is for 1968 383 motor and as you can imagine it's getting harder to come by. So my options are limited. How can I be sure that I am buying something that is good quality and not to used up AND how hard would it be to replace the worn out portions of seriously old internals of the clutch?
Great explanation of how a fan clutch works. If you still receive notifications from this I have a question. I had the timing belt and water pump replaced is it true that they should have replaced my fan clutch when doing the water pump? I read that the fan clutch will wear the water pump quickly on my 1988 Toyota truck with a 3.0L V6 if it was not replaced.
Thanks for the vid, I learn something new today 😁
The BEST video seen.
Absolutely fabulous ! Great Vid and subject matter. Thank You again .
Excellent instruction.
Very goo explanation good job cutting that one apart
hey brian. im just curious. where did you go on your trip if you dont mind sharing. wherever it was it was beautiful. reminded me of bermuda
Thanks for showing this video.
Thank you. Exactly what I needed to know.
Welcome Beau! Thanks for clicking like and subscribing!~
Hi Brian, I have 95 crown vic and my fan is always on, hot or cold. It has the same type of clutch as in your video. Is this normal and Can these clutches lock up?
If I put higher viscosity fluid inside would the fan be running all the time? I just want the fan to spin louder at low speeds for the cool rushing of air sound like in big diesel trucks.
Great informative video thanks
Excellent video again!I still watch your videos as a self employed mobile mechanic!ive learnt alot from you,keep up the good work dude!
Did you learn mechanics from Brian only?
no im a skilled technician with 10 years of main dealer experiance why?
I wanted to do mobile mechanic gig but wondered if self thought is enough... I'm doing level 3 in college and have no experience working for someone else...
you really should work for a garage to gain experiance.being self taught isnt always enough.
That what I was afraid of... I'm afraid I will screw few cars before I learn;)
Makes me think with all that work into it how can they sell them for next to nothing haha
For sure. I think because the fixed costs to produce units it's just materials at this point and the electricity to run the assembly line. They're being phased out. Overhead's never been so low.
thanks for teaching us.....
I have a 96 nissan truck and the parts both old and new look exactly like what I have. the old for sure and the new I picked up a O'Reilly's and is a IDC. my old one was doing the opposite. It was locked up and even though I could get it to turn by hand there is a point that it just sticks. now that I know there is no fluid in there maybe it could be cleaned up. I don't know. but I am curious how the new one has been working. I had about a month where I didn't notice anything and the fan was turning but no issues. It was a month later and I didn't even think about it being the Fan Clutch because it was new. But evidently mine is not engaging when it needs to and I heated is up to 220 and it is still the same. but when it is on the pulley and the Water pump *waterpump is good, when it is there and I suddenly hit traffic and it needs to cool things down you can hear it getting wobbly and just enough time to pull over because it reaches out and nicks the radiator. The fan blades that are attached to the Fan clutch move from that wobble just enough to nick the radiator and lose your fluid and get a tow home. I chased so many other things and I could not believe it when i realized the new one I bought was not working correctly.. So I am just curious if after some time did yours do good? I think mine was made by IDC for O'Reilly's. ayways, thx, kinda interesting coincdence and I am hoping the next one I get is not messed up. definitely will test it beofore I install it so I don't nail another radiator. that makes 5 aluminum and my OEM nice heavy duty one all from this crazy part and that no one thought it could be the culprit.
Thank you. You are OK
What would cause them to come on too early or be locked up all the time. I’ve tried 4 different ones... the engine and radiator temp are at 205.
Very Rusty Spring:
The other day I was towing our camper. OAT was approx 65*F. ECT went up to 238*F. No fan engagement at all. Clutch has resistance but I was thinking the fan clutch spring was very rusty like sandpaper and binding up. Thinking possibly the spring is not rotating.
Yeah I always wondered how those things worked like without wires from the ecu telling the clutch to engage or without having hot coolant flowing into the clutch to engage the sping that reacts to temperature. (I'm like I know they have a spring that responds to temperature but how do they know the temperature of the engine if they don't have coolant flowing into them to engage when the coolant is hot) The thing I still don't get is how do those clutches know to engage when the ac is on without any type of wires going to it???
thanks for sharing !
Thanks your awesome your very good machines to do that cutting with great detail explanation keep it up 3 thumbs up
I recall in the 70s n 80s...we would run a bolt thru the clutch to make it lok up....im having trouble w my 2014 tacoma.....its running 2014 on hiway...i was able to put my glove on and grab the fan blade and stop it from spinning😲🙈😲🙈😲
Great video. Thanks
Allot of info!! Nice visual
Nice video
Great info.
very good information thanks you
Nice video;
But you got that backwards: The feed hole (slot) is COVERED when cold, opens when hot...
(since you've cut away the case, you have the bi-metal spring out of alignment).
Also, this IS a fluid clutch, that moving vane releases the fluid into the clutch fins.
And the internal fins are NOT for heat transfer, they are there for the viscous coupling of the two plates...
The spring does NOT force them together.
The fluid must have completely leaked out, or you washed away what was left of it.
But VERY GOOD presentation...
Mr K L
Came for the fan clutch, stayed for the jet, liked for the dive footage :D
Thanks Tyrone!
Awesome!
do they always spin freely when they go bad? Or do they also lock up or get stuck half way? I guess what I'm trying to ask is can they cause a overcooling scenario at start up and idle when the engine is just started?
Generally, they can only get stuck on, or off, or loose fluid (off).
If the spring valve gets stuck in the 'hot' position, then it would run all the time (ie, if the valve shaft rusts and seizes).
But not likely, because usually vehicle sits with engine cool, and is more likely to get stuck in the 'off' position...
Of course anything that can happen, will happen... If it is 'crusty', I suppose it could open up (fan on), and get stuck there - fail to retract again when cool...
Mr K L
I think you got it wrong. According to my college book that spring just opens a hole for the fluid to flow. I think your old clutch just lost all the liquid that is why is dry. The new one got fluid inside.
It does seem to have lost all the silicone fluid that is supposed to provide the viscous coupling. When the temperature gets high enough for the bimetallic coil to turn the valve, the silicone fluid goes to the outer area where the interleaved grooves are, and allows the fan to be driven instead of freewheeling.
***** That is what I think. Thanks
Yeah i was surprised too. Coz always knew that there s silicone or some liquid in there.
Tank you my frind
Brian. Do you prefer an electric fan or a mechanical/clutch type?
He answered this question in the video.
Cool vid
What's your other channel
I had a tractor with failed fan clutch this spring, supplier did not have a new one so they suggested just to weld shut moving parts together so it would be constant fan on. At least tractor could work in the field...
I repair tractor and truck ac for a living. The majority of tractors I get in have a strap bolted to the fan clutch locking the fan to the clutch. They are easy to make with a drill, hammer and vise. Fan clutches on tractors cause more problems than they save imo. Anyhow my point is easier to make a strap than attempt to weld.
Question. Can a fan clutch turn either way or they are meant to turn either CW or CCW?
They will only work (correctly) one direction:
The fluid return pumping action occurs only rotating one way. (necessary to disengage the clutch).
Drive belt routing results in different vehicles having right or left hand fans...
[answered this for future viewers here]
Mr K L
Thanks for the video Brian. So there’s absolutely no fluid in this type of fan clutch? I think this is what I have on my 2003 suburban
condor5635 should be fluid in there. I replaced mine with an extreme by hayden 2786. 2002 gmc yukon. The temp would hit low 200's and at one point 230 towing a camper up a long grade. Right now, I can't get it above 199. I use a blue tooth elm127 obdII connector and monitor with torque pro. The engine actually cools off when parked and I increase the idle. Best move ever.
I definitely understand the concept of the fan clutch. I don't understand why there is any resistance at all when the clutch is at room temperature and the fan is not needed. At room temperature, the engine/radiator would be considered "cold," and the radiator would not require any cooling air from the fan. So at room temperature, there should be NO resistance in the clutch so the pulley can spin freely without resistance from the fan (with a cold engine, the fan would do nothing but suck engine power and lower efficiency). But if the clutch has resistance at room temperature, that means the fan will be turning when it's not needed. It seems to me that the clutch should be completely disengaged when the radiator is cold. Then, as the radiator gets hotter and hotter, at some predetermined temperature the bi-metal spring would turn enough to engage the clutch and spin the fan ONLY when additional cooling is needed. What am I missing?
It has to have SOME airflow to activate the sensor.
Without that, once it shut down in cold weather, then, with a tail wind, or parked, engine idling, it would overheat without kicking in the fan!
[answered this for future viewers here]
Mr K L
I don't understand what this spring does. How can that lock the clutch?
Gregory May when the spring gets hot it opens a valve that releases silicone fluid and the fluid flows into the grooves of the clutch that creates friction and makes the clutches lock and spin the fan. When the spring cools it closes the valve and the centrifugal force makes the the fluid flow back into a hole the fills the fluid reservoir back up. The lack of fluid causes the friction to dissipate and the fan to free wheel.
Does it matter which way the spring is wound?
Yes;
Has to be right for the design.
Most I have seen have a CCW (as viewed from the front) valve open rotation direction; but I have seen this done with both CW AND CCW wound bi-metal elements! - it depends on if the 'spring' they designed is expanding on heat, or contracting on heat...
It depends on if they put the higher expanding metal toward the inside of the coil, or wind it the other way...
(so don't get it flipped over, if for any reason you remove it...)
[answered this for future viewers here]
Mr K L
You just nid to clean and refill with new silicon oil. The one you open is compltelynm dry
Ever since these things first appeared back inn the 80's or so I was told a honey like viscvous fluid was used ....I believe when they wear the Viscous fluid leaks out and they can no longer work to put it simply...Ive grabbed and stopped many a fan blade on a hot engine while the clutch was freewheeling and the engine idleing with my bare hands showing off to my fellow mechanic friends when I was a teenager , I would let the back side of the blades strike my fingers and slow it down and then Grab the fan and hold it still for a few seconds while the engine was running...
LOL
Imports and domestic vehicles going back into the 80's all had a silicone fluid fill via a screw on the engine side. The closer the plates you exposed in the cut-a-way simply expose where the fluid is held. This fluid become thicker and thinner in viscosity just like most fluids, even oils as temps change, but it produces a drag between the drive and driven parts the control the fans speeds. Yours like everyone else simply failed as it developed a leak. The silicone formulated and injected is gone leaving no means of moving the fan to match or couple speeds with the circulation pump or fan block as some designed. They all had silicone fluid inside then between those cavities and gone because of a leak, it simply freewheels.
As for overheating at highway speeds, they normally are along for the ride and don't pull air thru the A/C condenser or radiator. Flushing the radiator core to have no insulation debris separate the fins & outside air or and engine problem was most likely you root cause of overheating under those conditions as the fan clutch had fail over winter or months earlier. The pressure cap holds 15-17 PSI on the coolant. Each 1 PSI raises the boiling point 3 1/4 degree F to 264 degrees F roughly (Yours may vary) but the clutch was not the problem at 50 MPH - 75 MPH with or with out the fan clutch functioning.
DK, ASE master tech since 78.
So this is different from a viscous because them ones spin and disengage fan blades when cold watch the the manufacture one above this don't confuse people with the difference none are supose to spin u till rad is hot
Very cool... errr no pun intended. I really wish we had access to the internet when I first let my curiosity about how things work, get the best of me... luckily, it was just a few black fingernails and lots of 4 letter words and nothing permanent
Time for a new Fan Clutch 1:07
I always thought it had fluid in them like a torque converter
The newer ones do- check out the one in the description.
This one did too; he is wrong...
Mr K L
Just found out it was fathers day....
tried 3 of the new junk fan clutches from china and my truck sounds like an airplane cold or hot. off and on all the time. new ones are cheap garbage. went to the junk yard with an original clutch for $30. no problems.
I hate mecanical fans, whenever mine turns on my pickup sounds like a semi trailer :(
Poor engine... Those clutches are reliable, but go tear out an electric fan from a scraped ford taurus or something. Tiny engines suffer quite a bit (or as much as alternator strain) and that pully puts too much torque on the pump behind it, causing your whole engine to heat up and strain from being heated up and straining.....