Fan Clutch

[auxbar]

Does anybody know how to force my fan clutch "on" to check to see if it is working properly? I can feel some resistance when I spin the fan by hand after the engine sits overnight, and when I warm up the engine, then shut it off and immediately spin the fan again it feels pretty much the same. I can't really tell much difference between fan resistance at hot and cold engine temps. I can not detect any leaks around the fan clutch assembly - but I have not removed it so I can't get the best look at it. I have tried to just start the truck and let the engine idle until it gets hot enought to engage the clutch, but it never seems to kick into high gear. I know what the roar sound of a fan coming on sounds like but I have never heard my truck's fan do that. It also has never overheated - so when it sits and idles it never overheats but I can not hear the fan engage either. I am not sure whether it is working fine or not. The only reason I suspect it may be bad is because my A/C seems to not work very well when sitting still. At what point do these fans kick into gear? Truck is an 02 Z71 1500 with 91k miles. Do those clutches "wear out"? Any insight anybody could give would be greatly appreciated. THanks!

[MT-2500]

After it reaches 200-212 degrees you should hear and feel hot air from back side of fan clutch when it kicks in.
If not time for a new fan clutch.

[auxbar]

What if engine never reaches 200*? Is that normal? The heater works fine in the winter, so I am assuming the therostat is OK.

Just curious. I will keep my eye on it, and if temp ever does go above 212* and fan doesn't kick in, then I will know I need to replace.

Thanks!

[MT-2500]

No not normal.
Turn it on and start it up .
Run engine at fast idle with air on and watch engin tempt and fan clutch and tell us how warm it gets and when fan kicks in.

[auxbar]

Originally Posted by MT-2500

No not normal.
Turn it on and start it up .
Run engine at fast idle with air on and watch engin tempt and fan clutch and tell us how warm it gets and when fan kicks in.

Ok, I drove around with air on for a couple of miles until engine was warmed up. I then parked in driveway, popped hood but did not raise it all the way - left A/C on and gently placed foot on accelerator to rev engine at about 1500 to 2000 rpm. Temp raised to probably 200* - that's it. About two clicks away from the 210* mark. My gauge goes from 160* on the low side, 210* right in the middle, and 260* on the high side. My temp never made it to the 210* mark. I did this for at least 5 minutes - which does not sound like a long time but it felt like forever. I never heard the roar of the fan. So I raised hood all the way and revved engine with the throttle cable under the hood - each time I revved it a little I could feel the fan pulling some seriously hot air back from the radiator - Like the fan clutch was engaged, but only when you gave the motor some gas. No major roar or anything like that. I'm sort of at a loss. I never hear the clutch "kick in" but when I give it gas I can feel it pulling some very hot air through the radiator.

[MT-2500]

If the fan clutch is working good you should hear it and be able to feel it kick in and start blowing a lot of hot air.
I would replace it .
Good luck
MT.

[ricebike]

another good way to test if the fan clutch is bad...

cool engine/ engine off... if you can reach into the center of the fan clutch and feel oily deposits... the silicone seal has ruptured & either the fan clutch would be so loose to be free-wheeling or seized up to run all the time...

guessing you have the former problem so a replacement is needed as MT stated earlier