i belive my clutch fan is stuck at full speed, never disengaging. how much would this affect my mpg and could it be the cause of my truck taking so ling to warm up. im pretty sure it is constanly engaged because i watched it the other day and it seemed to stay going one speed...FAST any help is appreciated

 

I've never given the fan clutch much thought because I've never had one malfunction, but I'm guessing your present condition cant be good for the waterpump bearings or the belt life. Maybe a trip to the bone yard tomorrow?

 

I know my fan never quit either. I replaced it with an electric fan.

 

so are u saying yours did the same thing as mine?

and how many fans? push or pull?

 

Back in the old days, back when carbs and points and drum brakes occupied many a Saturday afternoon, there was no fan clutch - the fan was always locked into its proportional speed with engine RPM.

With a clutch, the fan should always be spinning, to some degree. The cooler temperatures sensed off the radiator results in more freewheeling and less actual air-driving. One sign of a lock-up problem is that the fan will likely roar and be outputting a jet blast of air at higher RPMs, even without hot coolant flowing through the radiator.

You should be able to grab the fan and give it a spin (engine Off, of course). It should freewheel on the order of 1/4 - 1/2 turn before stopping. Any more than 1 revolution - the fan may not engaging enough to provide adequate cooling when needed. Any less - the fan may not be freewheeling as it should when not needed.

Also, see if you can 'wobble' the fan in a fore-and-aft direction - any significant movement here would suggest the clutch is shot, or the water pump bearings may have problems - depending on where the movement occurs.

Replacement clutches aren't terribly expensive - IIRC, on the order of $30-$40. With a junkyard, always taking some chance that the replacement may not be much better than the part being replaced. An electric fan is an option, but a little more coin and hassle to swap over. Either way, recommend to get a good one, not some bargain-basement econo-job.

IMO, suggest your warm-up time may be related more to the thermostat or a low starting ambient temperature than an over-active fan.

Good luck, and keep us posted. I'm sure up yonder in Wisconsin - a good heater comes in handy along about this time of year. :-)

 

it does "roar" at any temp, it seems to spin at the same speed as the engine and never speed up or slow down, i watched it a week or so ago while it warmed up and it stayed at the same speed

it will spin about 1/4 turn , and theres no play in the fan in any direction

im just thinking about getting ride of it and getting an electric one and hook it to a switch so i can leave it off while it warms up

 

mine had issues too...I have NEVER had one do that before...

I was going down the highway about 65mph and I could hear the engine rpm drop about 200rpm and the fan got louder...like a cold morning start...

gas mileage will drop..mine dropped 2-4 easy...mine would kick in and out going down the road and the temp gauge would reflect it...

if you find my electric fan thread you'll see...

I put a puller on mine wired to a relay and an adjustable temp switch...

 

A frozen fan clutch makes the fan sound like a Damn AirBoat!!! LOL!!! Theres usually no problem diagnosing this since its so ridiculously loud.

 

its sounds like a car without a clutch fan, just with a regular fan/flex fan, almost hear the fan over the engine if i have the hood open and im by the front of the truck, higher rpm...louder it gets

 

Sounds like an airboat to me. These are not flex fans and are very loud when the clutch is froze. If youre driving it down the road and people turn their heads and say HEY is that a damn AirBoat then its probably a stuck fan. Bahahahahhaahahhaa! Sorry for the fun but evreytime a fan sticks on me it just seems like the funniest thing. I guess I will never get all the kid out, If 31 years hasnt done it then its probably not gonna happen.