I have been researching the bennifits of a clutch fan.On my 1981 F-150 Ranger,AOD,302(5.0)would it bennifit me to install a clutch fan?It has just a steel fan attached stright to the water pump,I guess this is the factory set up.Would I gain anything by installing a clutch fan?Thanks All..

 

You will gain MPG and lose noise. The fan isn't needed at highway speeds but yet it is spinning furiously at that point, wasting gas and making noise. It is needed at slow speeds and at stops, and that's where the thermal clutch on the fan comes it.

But, I would go to a salvage to get one. Look for one that doesn't show signs of having leaked the silicon fluid out, and one that isn't loose. There shouldn't be any flex in its bearings and there should be reasonable resistance to turning the output when holding the input.

 

^^^ X2 with what Mr. Lewis said!

 

so as I understand,it would be a bennifit to change out the originial fan with a clutch fan?

 

So is it better to have a clutch fan verses a ridged steel fan?what would be better to save on gas?

 

The fan itself doesn't have to change. You should have a spacer between your pulley and the fan, and the clutch unit replaces the spacer.

But, I wouldn't go with the fans that flex and are, therefore, supposed to use less power. They don't have any input with regard to temp, and that's the key. Go with a clutch between your pulley and current steel fan.

 

Make sure the clutch has a warranty if you get it from a junk yard. They can fail without the fluid leaking out.
Once you install it, spin the fan by hand and note how much effort it takes, but it should spin pretty easily. Then run the engine up to running temp then shut it off. The fan should be significantly harder to turn by hand. If it isn't, it's no good.
Also, if the clutch has been lying on its back or front, leave it upright for a day or so before installing it.

 

If he goes with a factory type setup, he will need to change the fan.

The factory fans without clutches were of a flex type.

What I would do is get the rigid fan out of the wrecking yard, and get the thermostatic fan clutch new.

 

I bought the "Four Seasons" brand fan clutch when I replaced mine (available at Rockauto and other places). It seems to work well and was very similar in shape and finish to the original that it replaced. Made in USA (Texas).

 

That air cleaner wingnut can't be comfortable, Matt

 

Maybe he took the cleaner off to avoid damaging the filter and is in the stud

 

I am not sure that my 1981 Ford Ranger XLX F-150 came with a clutch fan origanally?Does anyone know if it did?It does have a steel NON flexable fan with a spacer on it.I just thought that a clutch fan setup would be a bit easier on the motor.Thanks for any feed back Guys

 

If you look in Matt's picture in post #9, you'll see a nut directly behind where the fan bolts to the fan clutch. You'll need to make sure when you take your fan and spacer off of your water pump that you have a large threaded section for a fan clutch to screw on. If you don't, you'll need to replace your water pump as well. Is it worth the extra effort and expense to make the swap? Most definitely yes. You'll have a more efficient cooling system and the potential to save fuel as well.

 

It wasn't so bad . I'm sure most of us have odd bruises and scrapes from crawling/climbing like monkeys around our engines.

 

This post above is misleading...

1983-1986-up 300-6 engines have the large threaded section to bolt the fan clutch to the water pump.

1980-1982 300-6 engines with fan clutches use four bolts to hold the clutch on. All you have to do is remove the spacer and swap fans.

The fan clutches are different between these years because they mount to the water pump different. The water pump is also different as concequence.

1980-1986 V8 engines use a four bolt fan clutch to water pump mounting system.


Here is the clutch fan on my 1981 with a 300-6. Notice the four mounting bolts holding it onto the waterpump.




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Some did, some didn't. They were a optional extra. Fuel economy models had them for example. You can buy fan clutches for your truck and engine very easily, it's getting the correct Rigid fan that's the hard part; that fan you will have to get at the wrecking yard. Look at Galendor's picture, (and mine just above).

From the factory, it has to have a flex fan to use a spacer, and to not have a clutch. The edge of the blades flex flat when the motor turns at a higher RPM. The flexing keeps the stress off the water pump and engine, but it also means it reduces the cooling of the fan. The faster the engine turns the more the blades flex flat, the less air the fan pulls to cool the engine. Very bad pulling a hill at low speed at high RPM.

The only non flexible fans from the factory came with fan clutches. Non flexible fan is pictured in Galendor's post. Notice the wider bolting pattern for the fan to attach to the clutch. The fan blades will not move at all and are very rigid. With a thermostatic fan clutch, this alows the fan to move almost the same amount of air at idle as it would at full engine RPM. This is ideal pulling a hill at slow speeds at higher RPMs. The amount of air the fan pulls is not changed by engine speed, it's changed by cooling need.

Having a rigid fan without a clutch will make a horrible whirring noise from under the hood. The horrible whirring only happens with the thermostatic fan clutch when it's fully engaged offering maximum cooling to the engine.