I was just wondering how other's fan clutches operated because I think my fan clutch is locked up too much. I have a 1995 5.0 with the super engine cooling package and a/c if that makes a difference. The clutch will disengage at highway speeds but in town below 40 MPH it is always engaged and I think it is adversely affecting my MPG. I can start my pickup in the morning and let it idle for 10 min and the clutch is still engaged until I take it up to highway speeds.

I have a 195* thermostat in it and according to my aftermarket gauge it runs between 190 and 195 most all the time.

So please let me know if this is normal or if my clutch is acting up.

Thanks.

 

Fan clutches are designed to lock up when the temp thru the radiator gets hot. When you are on the hi-way, ram air takes care of the cooling, and the fan free-wheels. In town, speeds are lower, so the fan takes over.
Depending on how new the fan clutch is, newer ones are more firmer and temp sensitive. Thermostadt ratings have no effect on the fan, other than the temps thru the radiator.

 

Are you sure its not disengaged?

These vicious style clutches never really freewheel. Unlocked then probably turn around 40% of the engine rpm. More then enough to make it look like it is engaged. Wen they do engage, depending on the application it will turn from 60% to 80% of the engine rpm. It should sound like someone put a plane propeller on the front of your truck.

on my truck, the fan doesn't really engage until about 210 degrees on my temp gauge. I have heard of fan clutches locking up permanently, but i have never seen it happen.

Here's a way to test the clutch. Take a piece of card board that will fit down behind the grill but in front of the radiator. Cut a 4in diameter hole about where the fan clutch is and put the cardboard in place. Let the engine run, but watch the temp gauge carefully. Dont let it get over 225 or so. You should easily hear it engage, especially if you apply a little throttle to increase the rpm. If there is no change in the amount of noise the fan makes or the speed it is turning by the time it hits 215 or 220 then the clutch is no good. Once your done, remove the cardboard and let the engine cool don to its normal operating temp before shutting it off.

 

Also, check the play in the shaft. With engine off, grab the fan blades at 9 and 3, (Oppisite blades,) and rock fan front to rear in a twisting fashion. Should have very little play.

 

I just put in a new fan clutch in my motorhome and when cold, it's always locked in, and stays locked in untill I hit a road where I'll cruise at a steady speed for a while before it unlocks. Sometimes, just stopping at a red light, it locks in again, once the transmission has shifted through all 3 gears, it unlocks again.

I think they are designed, that when you idle alot, no matter how cold or hot your engine is, it's always locked at idle speed, witch I find good for when it gets really hot in summer.

 

Sounds perfectly correct to me.. I just replaced mine back last fall because it DID NOT do what you say yours is doing... Now it works like it should...

 

After doing some more research it seems that what you guys are saying is about right. I did check for play in the clutch and there was none. I just feel like it being locked up a lot in town is really killing my gas mileage. But I guess that since it is unlocking and stays unlocked at highway speeds means that it really doesn't need to be replaced.

The thing that gets me is that my friend has a 2001 F-150 and when he starts his up cold the fan disengages after a couple seconds and mine just sits there sounding like its getting ready to take flight. Along with my dad's explorer and another friend chevy pickup, they don't sound like a plane after start up.

 

Oooooooooooooohhhhhh.......The fan on the bus goes round and round......See? Even kids know how it works.....ROFL

-Wes

 

Another question. Why is there only heavy and severe duty fan clutches available for a 1995 5.0 with a/c? All I can find is the heavy and severe duty clutches, and on the napa website it says a severe duty clutch requires at least 2.5 inches of blade pitch to disengage the clutch. How do I find blade pitch?

 

Grasp it FIRMLY in hand, extend said hand as far backwards as possible, now throw the fan as hard as you can.....Get a tape measure and measure the distance.....






























Jk....Actually have never heard of it before...

-Wes

 

When you first start your pickup for the day, your fan should only be heard for a couple seconds...

I went through 2 new fan clutches(OEM one wasn't kicking in at all) untell I got one that would work how it should.. If you pull out onto the hwy, the fan should disengage in a short amount of time(unless your motor is running hot) I had one that would take about a mile at 60 mph to shut off. That just isnt right.. the one before that would kick in at a stop light and not shut off untell the motor was reved up to 3000 rpm for 30 seconds...

The one I have now, when the motor is cold, start the pickup, and before it comes off high idle, the fan is disengaged. It shouldn't have to kick in hardly at all in moderate weather (60-70*) unless you are working it alot.

 

Thanks hav24wheel, that is what I was looking for. I knew my fan clutch had to be acting up. So where did you end up buying the one that is now working properly?

 

Oriellys... But thats where I got the first two... But it had a warrentee so got them exchanged for free, just out the 10 min it took to install.

 

hav24wheel is right. It shouldn't be engaged often at all. Even in the 100+ summers and pulling heavy trailers, mine only engages when in heavy traffic. And it will stay engaged for a minute or two before it has moved enough air to cool the engine, then it disengages.

I got mine from oreillys and the first one lasted about a year, but the second one has last quite a while now.

 

Thanks guys. I'll probably go get me one sometime.