87m6chris

I have been searching the archives an hour now and can't find the description of what a working fan feels like hot and cold.

Just replaced the clutch fan (along with everything else in the cooling system) with a new one from NAPA and it is quite stiff to turn when the engine is cold but after a ten min. drive and engine up to operating temp. the fan is very easy to spin with engine turned off, that doesn't sound right to me. Shouldn't it be very stiff as if locked to the water pump?
Thanks,
Chris

fantic238

If you can stop the fan with a thick piece of carton when the engine is idling hot, then the viscous clutch is bad.

djb383

A safer way to check the fan clutch is with the engine OFF, give the fan blade a spin by hand.........it should stop in less than one revolution, if it's still good, keeps spinning if bad. A viscous fan clutch is never locked.......if it is, that's bad.

fantic238

Yup, my test is quite brutale..

milmat1

Also check that the fan does not move back and forth )Play!)

93XJLI

if it doesnt sound like a 747 on takeoff when the motor is cold in the morning and you step on the gas, its shot.

jeepride

Stick a broom handle in your fan clutch hold it tight and start engine if the broom handle kicks out of fan blade your clutch is good if broom handle does not move your fan clutch is bad.

nasonguy

No kidding, I had a buddy that started his car one day, little did he know that a cat had found its way in to his engine bay, and was sleeping IN the mechanical fan. Holy *&%$ that was nasty, it was like cat soup afterwards....

caged

haha, don't stick a broom handle in there. lol.

ZachsXJ

...do you have any concept of how bad an idea that is?

djb383

The problem/sad part is someone may read that, not know any better and try it.

Fuzzzymaster

Whats the difference between a clutch and viscous fan.? How to identify?

fantic238

Generally speaking, it's the same thing.
Technically speaking, the fan hub has an automatic clutch that is made by a disk rotating in a viscous thermo-hardening fluid, when the temperature reaches xx the viscosity increases and the hub housing where the fan is attacched is dragged together with the hub.
At temperatures lower than xx, or when the clutch is bad, the viscosity is not enough to drag the fan, and will just spin slowly for inertia.

nasonguy

For that matter, I wouldn't recommend sticking ANYTHING in there, even card board. That fan can be dangerous, you know that illustration on the shroud of peopls fingers being severed? Yeah, that thing can take off your whole arm, lol.

fantic238

Yes i you're right, you might not lose an arm but certainly get seriously hurt if you don't know what you're doing.