Fan Clutch gonzo for the 6th time, what is causing this?

[GShail]

Well this one lasted about 5,000 miles. Once again I am getting high water temperatures particularly while climbing grades or when loading the engine when just starting out.



Whenever a dealer sticks the DRB on my truck, all they can seem to tell me is that Fan Pulse Width modulation is at max while fan speed rpm is low. Then they tell me I need a new fan clutch. They replace it under warranty. Everything works perfectly for a while, then . . . a few thousand miles later my AC temps become warm at idle, and then within 1,000 miles the fan clutch goes down for the count.



This problem was occurring prior to my installation of a new ECM, TST or any other upgrades.



Things I have done to correct the problem.



1. Cleaned the AC, Radiator and Intercooler fins with a degreaser. They were a bit dirty but not too bad.

2. Relocated the ground wire from my TST to the inside dash panel.

3. Replaced the coolant.

4. Checked the radiator hoses, they Do Not collapse.





I am at a loss as to what I should do, my truck runs great with lots of power, good mpg until this creeps up.

 

[67guzzler]

This is a reach here but could there be a centering problem with the fan to the pully? If it was out of round, would that cause unnecessary vibration and result in the failure of the fan clutch? Is it even mounted to a pully? Can the pully be replaced? Just a guess! I hope you get it solved. Frustrating!

 

[rbattelle]

This is a reach here but could there be a centering problem with the fan to the pully?

That's what I was thinking too. Typical dealership will just fix the symptom rather than treating the root cause. If you keep blowing fan clutches, then something that's driving (or driven by) the clutch might be out of whack. Could be a major fan imbalance. Or, as JGann points out, the fan drive pulley might be out of whack somehow. The fan is not attached to the water pump; it's on its own dedicated pulley. Since you've tried everything else under the sun, I'd say replace that pulley next.



-Ryan

 

[GShail]

Will check that pulley tomorrow. Any other ideas?