fan clutch.

[robmoore11]

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]

You can turn it by hand with the truck off. A good sign that it's a working clutch is when you start it cold in the morning, you should be able to hear the fan kick in and make a bunch of noise for the first few seconds the engine is running. This is the fluid making it's way back to were it belongs after sitting overnight.

Here's how I locked my fan together. Doing it this way prevents the fan from unscrewing when you stop the engine.

You must be registered for see images attach

 

[FORDF250HDXLT]

with fuel around $4 a gallon,the last thing you want to do is bring the efficiency of the engine downward.
this may "appear" to be the cheapest way out,however it will just drive the price per mile up doing so,which will cost you much,much more than if you just replaced the clutch.
you should consider replacing it and at least research the electric swap too.which will do just the opposite of locking a mechanical.

 

[IDIDieselJohn]

I like my fan clutch, but I really do NOT recommend locking it full time.

Your mpg will be reduces along with your power. When these lock in, they suck 25HP from the engine.

Buy a new one, I installed one a brand new on my motorhome last year, couldn't be happier with it!




Or as XLT has said, an electric one ain't a bad idea. You can control it your self with an in cab switch and a real temp* gauge.

 

[MR.T]

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.

Being able to turn it by hand is a good sign, not bad. In the summer it's pretty easy to test it by holding the throttle open to roughly 2000 rpm for a several minutes while looking down at the fan clutch. If you have A/C, turn it on to speed up the test. If the fan clutch is working you should see and hear the fan speed up and cycle on for about a minute as the air leaving the radiator gets hot enough to engage the fan clutch. I'd expect engine temp to peak around 210F. Note that some clutches engage slowly and reduce the air temp before fully engaging, others may engage fully rather quick.

This test presumes the rest of the cooling system is working since heat has to get transferred to the air in front of the fan clutch in order to raise the temperature of the sensing element.

It's not a perfect test, but you'd need an optical tach and some temperature instruments to do much better. If it passes this quick test above, it's probably working fine.

 

[Brianedwardss]

Depending on how you use your truck, locking the fan can be a benefit, not parasitic. Being that I use the 88 for commuting, the stock fan clutch could not keep the truck cool while sitting in traffic with the AC on. Locking it on was the best thing I've done for it in that regard.

If you have alot of highway time, clean off the radiator and condenser, then drive it again. If it still gets hot, probably time to get a new clutch. Just make sure air can flow freely through the radiator area or a new clutch won't make a difference.

 

[IDIDieselJohn]

You get hot in traffic?

My camper runs below 180* (below 180* thermostat sitting in 100* weather with A/C blasting. My new fan clutch locks in when engine idles for a while though, cause after a few stops and goes, it's locked in and very noticeable the noise.

Even before my new fan clutch, it would always run cooler (below thermostat) sitting in traffic. Only time my 6.9 gets warm is when it's working.

 

[Brianedwardss]

^ Forgot to mention that 6.9L's cool WAY better than 7.3L's. I've never had heat issues with 6.9L's, but 7.3Ls have a port plugged off in each head, and as a result they get hot much much easier.

The OP's truck has a 7.3L most likely

 

[IDIDieselJohn]

Oh yeah that is true. Forgot about that.

Wow would it make that much of a difference?

 

[Brianedwardss]

If it's hot, and your sitting in 4-lane stalled-traffic twice a day in a 7.3L, and wanna run the AC, it's a good option. If you cruise the highway alot or just run around empty, it's not really necessary.

Just depends on how you use the truck, and even then, only 7.3L's like to get toasty

 

[MIDNIGHT RIDER]

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.

 

[Kevin 007]

I bought two new Hayden clutches in the last few years for two different 7.3's and I have NEVER heard them lock or un-lock at any time. No matter how hard im working the engines. When I start the engines cold, the fan is spinning fast and always seems the same at idle, hot or cold. don't know what its doing as im driving down the road however.


I have a sneaky suspision that my new clutches were not working as they should. I think they are always locked. My current daily driver is one one of the trucks that I mentioned.

I also have never had a fan unscrew it self...they always seem tighter than hell after just a few minutes of running like MIDNIGHT RIDER said.

 

[IDIDieselJohn]

Listen to my fan clutch! Very noticeable!

http://www.youtube.com/watch?v=A66ovOsoeUo


Climbing hills, I always keep it throttled around 3/4 (just before seing black smoke) as I don't have an pyro yet, so i'm controlling my EGT's with my passenger side mirror and as soon as the fan clutch locks in, it's gonna start smoking with no changes in throttle and looses abit of power. This thing is dragging a house on it's back so I can understand, but I do feel a differences!

 

[Kevin 007]

I can't listen...dial up even slower than normal dial up. But im sure it will clear things up for others, thanks for posting that man!

 

[Simp5782]

Never heard mine kick in. She runs around 190 empty. 210 at max with my GN behind me grossing 17k. Took a 900mile round trip haul to pick up a truck. She ran about 205/210 grossing 32k. She didnt kick in at all. I was holding 30/35 up the 6mile long 6% grades in 3rd.