Hey Guys,
Been posting about real bad fuel mileage on my 2000 S10 Blazer, did just about everything imaginable to improve mileage (10-11). How can you test the fan clutch? It kicks in about 2500 rpm's is that right? I got about 100,000 on the clock. I know when their bad they kill the power/mileage but this runs real good. Any one want to way in? Thanks.

 

no...no thats bad.

Fan clutch should kick off at 1800 rpm or so. I had the same problem. I would accelerate, and would have a huge vacuum noise (fan), but instead of cutting out, it would stay engaged all the way up through 3k rpm. It killed power and was obnoxiously loud..

I replaced the fan clutch, and went up about 1.5-2 mpg. Between the fan clutch a tune up, I got from 12-13 to 15-16 mpg cityish driving. You can test it by spinning the fan by hand with the engine cold. The fan should spin pretty freely..mine was failed and fully engaged all the time, so even with a cold engine a hard push would only spin the fan one blade over.

 

when the fan clutch has been run awhile and becomes ("hot" Lets Say) the clutch should be easy to turn by hand, when the truck has not been started the fan clutch should be hard to turn by hand.. also if your a dare devil, you can hold onto the the actual fan while someone starts the truck!! if the clutch fan is no good you`ll feel it want to jump with the start of the engine.. If that happens (let go) dont hold it anymore..and replace the clutch

 

I thought we had a thermoviscous fan clutch...meaning it uses a fluid to engage and disengage...so as the fluid heats up it engages (as the engine needs more help cooling). With my new fan clutch, I never get the fan roar after start up. Only when the engine is hot and I restart while the engine is still hot do I get the start up roar (before replacement it roared every start up, every time)


Edit: If I recall, swartlkk had posted a video of him stopping his fan by hand when the engine was cold and running (fan clutch is simply free-wheeling at cold temp).

 

http://autotechrepair.suite101.com/a...clutch_testing that may help ya out....

 

I'm gonna agree with you, Jason. On a cold engine, with a properly operating fan clutch, the fanshould spin easily by hand. A shot clutch will cause it to lock up.
When I say 'spin easily by hand' I mean it should make a few turns, but not just keep spinning.

 

Where do I get a fan clutch removal tool w/o gettin raped ? Anyone buy 1somewhere online?

 

I used a very large adjustable wrench on mine...

 

Clockwise/or counter clock and what did you use for a hold back?

 

I actually dont rem how i locked it up to loosen it i`d have to go outside and look at it againLOL If your hands are strong enuff to hold onto the pulley on the water pump, put the wrench on the big nut and hit it with a hammer, that should break it loose, If not can ya come to Long Island and i`ll give ya help with it,, doh.