i was wondering how do i tell if the fan clutch is gone? i just read on another forum that you are not supposed to be able to spin the fan by hand when the truck is off. but i can, both ways. if the case is my fan clutch is shot. i was wondering what the procedure is to have it totally locked? i cant find anything on how to lock it. i would atleast like to try it out because i found a video of what its supposed to sound like with it locked and unlocked. and my truck does not sound like it is locked.
franklin2 has the best
solution, unless you can find a direct-drive hub that eliminates the clutch completely.
I have done been all over the fan-clutch situation, all episodes.
I have yet to actually see with my own eyes a fan-clutch that actually works.
Also, if they do make some effort at spinning the fan any faster than coasting along, it is at high engine and ground speed, NEVER while sitting in traffic in 100* heat when it is needed the most.
Fan-clutches are a relatively new invention that were unheard of until the mid-80s.
I own and have driven countless vehicles that never had any provision for a clutched fan; thy were all direct-drive from the factory.
Even at "full lock-up", a clutched fan only spins at about 80% of fan shaft RPM and it takes a "severe duty" unit to even claim that (although like I already stated, I have yet to actually see one work).
I have been pinning/locking fan-clutches for years and many many miles and I have not experienced any of the negative issues that others are wary of.
As for the fan self-screwing itself off upon engine shut-down, I have installed them, ran them maybe five minutes, and then them already be so tight that I would kave to knock them loose with a mallet, and this with a very generous coating of anti-sieze on the threads.
I finally was able to locate genuine direct-drive fan-hubs to fit the 6BTs that we have and was able to get rid of those big heavy chunks-of-junk clutches.
Up until then, I had always kept two complete fan-clutches for each engine; one completely locked for summer use and a normal un-molested one for cold-weather use, swapping back and forth in spring and fall.
MEANING, I have had much experience with both locked and free clutches on the same engines, six months of each every year.
That being said, neither myself, nor any of my family or drivers, has ever noticed the least difference in engine power or fuel mileage with either style of clutch, locked-up solid or free-spinning.
I would be ashamed of an engine that was so puny as to even notice what little effort it took to spin a little bitty old fan; why, I have several house fans that turn ten-times as fast, with twice the blade diameter, pushing twenty-times the air, and they have little old 1/8-HP chinamotors.
Again, I must commend franklin2 on his locking device design; that is the best I have seen yet.