Clutch Fan Engagement Question

[farmtruckman]

At what temperature does the clutch fan engage at? 96 4.0 overheating only when AC on. Beyond the usual suspects, thinking that clutch fan never seems to engage.

 

[gmanpaint]

Temp wise, I am not sure. It doesn't turn on with the fluid temps or the block temps. It turns on when the ambient air flowing over the top of the radiator gets to hot. In the center of it, there is a simple spring coil that heats up and activates a bypass inside that allows the internal fluids to make the clutch engage. Once air temps are cooled on the coil, it closes the bypass, thus shutting off the clutch engagement.

Does it run (can hear it) on start up for a min or two, then shuts off (gets quiet)?

If it runs for a few seconds or not at all on start up, get a new one. When working correctly it should run a few mins on start up. Hayden makes good clutches, and I just installed a severe duty on mine. Amazing how well it works.

 

[greasemanicure]

I had this same question on my F150. An old friend, with all his fingers intact, suggested that I get an old 3 or 4 inch paintbrush and see if I could stop the fan with the bristle end after the engine is warmed up. If you can stop it this way, the fan clutch is toast. Another way suggested on the truck forum is to tie a thin string to one of the blades. If the string could stop the fan, toast again.

 

[SoNic67]

Get a newspaper, fold it and try to stop the fan with warm engine, A/C running and right after opening de hood (not cold, it won't be engaged).

 

[Lube]

AFAIK, the makers of these things recommend that you replace them every 5 years.

 

[Maniak]

According to Hayden...

Engages at about 170° radiator air temperature, (about 30° lower than coolant temperature).

I always use the severe duty fan clutch from hayden if I can...

Severe Duty Thermal
Turns the fan 80-90% of the shaft speed when engaged.
Turns the fan 20-30% of the shaft speed when disengaged.

The severe duty isn't the best for gas mileage, but it helps keep our vehicles cool in 105F+ weather.

~Mark