trouble shooting the fan clutch
 

Whenever the car is running, the clutch fan is always on. After doing some reading I'm thinking that the problem is my clutch but not sure. Is there a way to determine if the clutch is bad? I'm also guessing that the fan control module and the cooling fan switch regulate the electric fan and not the clutch fan. Am I right about that?

I have a 97 2.8 12V quattro.

bump.

the vicious fan (attached to the crankshaft) or the electric A/C fan?

yes the vicious fan is always on, it is not controlled by anything electrical.

the viscous fan is the one I'm talking about. Are you saying that the viscous fan is always on? I think there's a viscous clutch on the fan that engages and disengages depending on the temperature of the engine.

does anyone else have any experience with bad clutch on the viscous fan? I wonder if the clutch is not stuck or something, if that's even possible. Or maybe some control module gone wrong? Can anyone put me on the right track please?

the clutch on the fan is only to disengage the fan at high RPMs. if the engine is running the fan should be spinning.

got it. Thanks! My fan doesn't disengage at high RPMs, it just roars on and on... so I'm guessing it's the clutch then. Thanks for your help ghost!

well the disengagement point is rather high, i dont know specifically but probably at like 4-5k rpms and up, so you wouldnt really hear it. if you are driving between 2000 and 4000 rpms then yea the speed of the fan is going to increase. when you really get on it though the clutch kicks off so it doesnt over-spin and explode and also so it doesnt pull so much power off the engine.

It is my understanding that when the engine is not running, you can rotate the main fan (the non electrical one) by hand with a bit of resistance however you should not be able to spin it.

I happen to be able to spin mine and it needs to be replaced. Someone told me that I need to remover the bumper cover, grill and radiator to perform this job. Please tell me some one has figured out a better way to replace the fan clutch!

Can someone walk me through the basic steps of fan clutch replacement?

Thanks in advance!

Bald Bill
1998 A4 Avant 2.8

Well... I decided to actually take a look under the hood. It took under three minutes from opening the hood until I had the fan and clutch out and the hood closed.

Tools used: 1-1/4" open end wrench (I didn't have a big enough metric wrench and the 1-1/4" fit like a glove...so it must be a 32mm) and a flat blade screwdriver.

Procedure: place screwdriver in slot on engine side of fan clutch assembly, place open end wrench on nut and "tighten" to remove nut.

Now I just need to order a new fan clutch....

does a bad fan clutch make a whirring noise at all?