Fan Clutch issues

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petrotk40

petrotk40

10 Year 15 Year
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I had another thread entitled heater issues, but the issue is with the fan clutch not the heater.

There doesn't seem to be any great threads about this issue or how to remedy it. It seems as though my fan clutch is sticking. I get a vicious roar on startup even in cool ambient temps. This roar goes away if I get up to ~3k rpms, I can actually feel the fan clutch pop and disengage. I need to at least drain the fluid and replace it, but with the sticking issues I'm worried the clutch is shot. Has anyone else had a similar issue? How many people have replaced the fluid or did you just buy a new clutch?

Thanks!

edit:

is this the right fan clutch if I were to just replace it? Are fan clutches shipped with fluid already in them?
http://www.amazon.com/Aisin-FCT-021-Engine-Cooling-Clutch/dp/B00829HCD4/?tag=ihco-20
 
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Shortly after purchasing my '99, in 2005, the A/C wasn't blowing particularly cold air especially noticeable at lower vehicle speeds (trails). A/C shop in Reno found a faulty fan clutch and installed a new FC. Fast forward a few more years and I was having, during a Utah explore, engine cooling issues.

After returning home from that trip and instead of replacing the fan clutch (blue) I opted to try the drain and fill of the silicone fluid. I remember it took a couple days for the fan clutch to fully drain the old fluid out. Then I filled it with a mixture of 7500 and 10000 CST silicone fluid I sourced from a hobby shop. IIRC from the very limited info available at that time OEM fluid is in the 3500-5000CST range?

The fan clutch with the new thicker silicone seemed to stay locked up to about 45mph...completely solving my slower speed/wheeling on trails cooling issue. But it came at the expense of about 1-1.5mpg(!)...no surprise there given the air/fan noise from my modded fan clutch. On my list of mods to try: An electric fan out of a ~'06 Lincoln, etc., Town Car (had a buddy who installed on in his V8 Bronco and was quite satisfied with its cooling performance...and zero MPG hit)...still on my list :D

Since doing that mod back in the summer of 2009 I haven't touched the fan clutch; however the fan noise isn't as prevalent as it was that first year or two...presumably from the shear effect of now older silicone fluid.

Typically a fan clutch will fail if the silicone fluid leaks out or the bi-metal spring gets so corroded it can not perform. The typical symptom of failure AFAIK is one of not being able to cool the engine/engine coolant effectively especially at lower vehicle speeds where air flow through the radiator is abbreviated...

Yes...fan clutches are shipped with the fluid already installed.
 
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Ok great thanks.

So it sounds like clutch/fluid failure is diagnosed by the fan slipping or not engaging. I have the opposite problem. Thoughts on that?
 
I will test this and report back. This all seemed to start when I accidentally tried to start the car while it was already running :bang::bang:
 
Sometimes it does help to double-start. You just need to remember to also shut it off twice. ;-)

With that little bit of information, are you certain that the starter gear isn't sticking out and the 'roar' is the spinning of the starter assembly? Slim chance it, but throwing it out. Hard to diagnose a 'roar' over the net.
 
Per hoser. If the fan clutch is locked up then its either a seized bearing/bushing or the bi-metal spring is not functioning to allow the silicone to move...and replacement is probably the easiest/best approach.
 
I didn't feel much if any difference in fan resistance between cold (90) and warm (190). I don't think it has to do with the starter because when I get to stoplight and idle, the noise comes back.
 
spressomon said:
Per hoser. If the fan clutch is locked up then its either a seized bearing/bushing or the bi-metal spring is not functioning to allow the silicone to move...and replacement is probably the easiest/best approach.
Click to expand...

Is that clutch in the amazon link above the correct one? It's half the price from Lowe Toyota
 
^ looks like it; however I can't say if its identical to OEM or not. Yes the OEM is rather spendy it seems! I assume you contacted Onur/beno for OEM pricing?
 
petrotk40 said:
I didn't feel much if any difference in fan resistance between cold (90) and warm (190). I don't think it has to do with the starter because when I get to stoplight and idle, the noise comes back.
Click to expand...


The fan should rotate with little resistance when "cold". Whereas with a properly functioning fan and fan clutch it should be 'locked' and not easily rotated when the engine is quite warm/hot.

Based upon your comment about the fan clutch staying engaged until about '...3,000rpm' I would say that is commensurate with how mine was for the first year or two after installing higher CST fluid. With presumably some shear wear of the fluid I don't notice mine making as much air noise at 3,000rpm compared to a few years ago...

I'm not positive what RPM and/or the temperature OEM is designed to engage/disengage...

If you have the blue paint/colored fan clutch you can easily and inexpensively drain and fill to try before replacing (I can't remember but I think the fan shroud needs to be raised with the fan to fully remove from the engine bay...). I find the Klein strap wrench to be the best for removing the 4 stubborn/tight nuts that hold the fan.

Since your fan clutch seems to be staying locked to a higher RMP/temp than necessary you might try filling with 3500-5000 CST silicone for starters.
 
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spressomon said:
The fan should rotate with little resistance when "cold". Whereas with a properly functioning fan and fan clutch it should be 'locked' and not easily rotated when the engine is quite warm/hot.
Click to expand...

This is what makes me nervous, why would the fan be locked up when cold?
 
petrotk40 said:
This is what makes me nervous, why would the fan be locked up when cold?
Click to expand...

The bi-metal spring could be corroded/not closing properly and/or bearing/bushing failure.
 
I'm just going to go ahead and order a new clutch... it's my DD and time is $$. Thanks for the help spresso and hoser
 
Mine went out at about 255k. Was having 90k done so it was easy adder.
 
Any tips for getting the clutch off? I am having trouble removing the nuts without turning the whole crank...
 
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