So I have been diagnosing an overheating issue - can be found in this thread here:

https://www.ford-trucks.com/forums/9...tions-hmm.html

I am suspecting my fan clutch - as it spins the same by hand cold and at 210 degrees (by mechanical gauge I have installed).

So when it was hot today at 210 degrees - I took a video of the fan when I turned the engine off - should it free spin like that for that long? My buddy has a Duramax and his stops almost instantly on when he turns his truck off.

Here is the link to the video:
MPG: YouTube - Excursion_Fan_clutch.MPG

You can hear when I turn the engine off and see how long it takes for the fan to stop spinning - again this is at engine temp of 210 degrees.

Anyone shed some light on this?

Thanks,
Joe

 

I would call the fan bad. At that temp it should be pretty hard to turn. Although as long as your travelling faste rthan 35 MPH the fan does nothing. Forward motion will move enough air through the radiator to cool things. A bad fan will only cause problems in slow traffic or stop & go driving conditions.

 

The time that the fan takes to stop after you turn off the engine seems normal with a warm engine. Does the fan roar when the temps get high? With the engine running, the fan can be turning somewhat even though the clutch hasn't engaged to provide greater cooling. The clutch is a viscous clutch (using oil to engage) and won't provide any resistance to turning when the engine is not running. It needs rotational input from the water pump shaft to operate. Changing the fan clutch is an easy and "dry" thing to do.

Have you checked the radiator for plugs inside and outside? I read in your other thread that it may have been replaced/cleaned but I would check it for myself. You don't have enough miles on the truck for the water pump to be going bad but stranger things have happened. Sounds like you will have to start eliminating one thing at a time to determine your problem.

 

Ok - that is what I was not sure of - only thing I have to compare it to was my buddy's Duramax. As for the resistance of the fan clutch - if I spin it by hand it will travel about 1" after I let go - pretty typical to just the viscous resistance - and it is the same cold and hot. I know on my CJ - when hot the clutch cannot be turned by hand really - that is what had me wondering...

 

Try to stop the fan with a rolled up news paper when the engine is hot. You shouldn't be able to. If it stops, or slows down a lot, the clutch is bad.

 

And this is where the warnings come from for fan belts. "Be sure engine is stopped before installing belt"

HA!!!


**Sorry couldn't resist.