fan clutch

[cryptokid]

when the engine bay is cold, if the fan easier or harder to spin by hand compared to when the engine bay is hot?

i think the fam should be harder to spin by hand when the engine is hot, but i have limited expierence with these type of fan controllers.

 

[crossbow]

How's the car start up? After it cranks, does it sputter and feel like its gonna die for a second (until you give it a tap of gas)...

I had a weird irratic startup idle, and it turned out my heavy duty clutch fan was engaging the second the car started (instead of spining freely).

 

[Virtuoso]

If you can hear it that much, probably time to replace anyway.

The fan clutch in my old 5.0 got so bad, when you went above 3,500 RPM the belt would squeal. Not pretty

 

[QuadDriver]

It will fail in one of 2 ways. If all the silicon goo inside gets out, it will freewheel when you shut off the motor, maybe make a little noise, eventually seize to the shaft and cause belts to break.

Otherwise, they can get stiffer and stiffer, if it sounds like you have a fan running, it will break belts.

 

[Ugly3]

We used to duct tape a fan blade to the shroud and run the engine. In a few minutes the fan would rip loose from the tape if the hub was good.

 

[Russ]

As far as I know, all you have to do is try to spin the fan by hand when the engine is off (I don't think it makes any difference if the engine is hot or cold). If it makes more than 1 or 2 revolutions after you let go, then you need a new one, if not, then the clutch is still good.

 

[digitaldrifter91]

how can i tell if a fan clutch is bad? my fan clutch has a little so called thermometer on it that senses the water pump heat..turning on and off or should i say freewheeling and relesing.

mine is pretty stiff...but when its warm its slightly stiff with some resistance...i heard mixed reports of it being too loose or too tight to tell if its bad.

any of you gurus have any idea?

i hear it all the time now..its a rocket! in hot OR cold weather.

1986 300zx...

 

[digitaldrifter91]

quote:

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Originally posted by Ugly3:
We used to duct tape a fan blade to the shroud and run the engine. In a few minutes the fan would rip loose from the tape if the hub was good.

---

good idea

as for the resistance...i have to pretty much push this thing...its like pushing a door open with 1 finger, that type of resistance maybe more...

when its cold its pretty stiff when its hot then its about the same...

when the engine starts its loud, then it calms down after about 30 seconds, which is normal. runs fine at startup.

i had belt squeel just recently..tighten the crap out of a belt to fix it, finally got it to spec at .4 inches...it was origionally at like 2 inches.

 

[HerkyJim]

For a procedure/technique, go to www.ackits.com the forums section and the FAQs for how to evaluate the condition of a fan clutch.

my $0.02

 

[digitaldrifter91]

ok today was differnt. when the car was off it was kinda stiff as i said before, but then after i ran it for 30 minutes i did teh check again immediatly...and it was pretty smooth...not too grippy, but not alot of play...like if i push it, it turns a blade or 2..not like before, not even moving haha.

so humm

thanks btw.

 

[mechtech]

A mechanical fan clutch should spin with a little drag cold, but have increased resistance [by hand turning] when hot.
If it is roaring at idle or cold, you need to replace it.
A bad fan clutch will actually hurt gas mileage.

 

[theguru]

Better still fit electric fans and do away with the clutch fan.

 

[digitaldrifter91]

hey update:

when car is cold i turn the fan...its soo stiff now, it barley turns when it does it moves an inch gets stuck then moves again.

on freeway speeds all i hear is the fan...

past 3400 rpm it screaches....

when the car is hot and i turn the fan it is still hard, but not as hard as cold but still moves an inch then doesnt at all.

is aftermarket clutch fans good?

 

[digitaldrifter91]