Let’s talk fan clutch

saburai said:

Seems reasonable. I would caution that products like PB Blaster, Liquid Wrench and the like contain solvents that could potentially destroy or damage any seals it comes in to contact with. I'd be more comfortable using something similar to what ever is inside the clutch itself.

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Yeah, applying it how they did might not be the best idea. I just want to spray it with wd40 while it's installed. Just a little something to help it if it's a bit stuck. Any excess will run down and drip off, not soak into the unit.

you loosen tension on the spring by either bending where it connects in the outside or popping it out and cutting a new slit for it.

At one time there were fan clutches made with an adjustable spring tension it had a screw, slot and graduated scale.

Just bite the bullet and buy another ford fan clutch. The aftermarkets do not work. The electric clutch mod is superior if you want to do that.
I bought two off u haul that work perfectly. Paid $125
If your truck sits overnight when you start it it should be locked up and stay that way until you get the rpms up. Mine won’t unlock in the morning until I get up to 2000rpm

ironworker40 said:

Just bite the bullet and buy another ford fan clutch. The aftermarkets do not work. The electric clutch mod is superior if you want to do that.
I bought two off u haul that work perfectly. Paid $125
If your truck sits overnight when you start it it should be locked up and stay that way until you get the rpms up. Mine won’t unlock in the morning until I get up to 2000rpm

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That is true. Every clutch fan I have had on different types of vehicles was locked up when first started, no matter what the temperature if it had sat overnight. It varies, but after a few seconds to a minute or so, they will release. Something about the fluid settles in the clutch in certain places and it locks it, and then when it spins the centrifugal motion moves the fluid back to where it belongs and free's it up.

It’s supposed to be locked when you start it.

This is actually a good tutorial. I assume most of them are similar.


tps://www.haydenauto.com/en/search?q=Tutorial

I think that will get you there.

Agreed on the new Ford one. Same results for me with aftermarket. I leave the Ford part number for consumable parts like fan clutches water pumps etc in my ebay search. I have a Motorcraft fan clutch in stock less than 1/2 price.

I put a brand new motor craft fan clutch on mine and it didn’t help.

One thing that will really throw a fan clutch off is a plugged radiator. Either internally if a cluster of tubes are plugged in the core stopping coolant flow or if airflow through the core is restricted by dirt bugs and debris. The coil in the front or the clutch must be exposed to the actual air temp.

Over the past 40 years dealing with overheating garbage trucks and landfill equipment I have found that many times we think the core is (externally) clean but on close inspection it actually isn’t. Put a light behind the radiator and be sure you can see light though.
Sometimes pulling a radiator that looked clean it was actually plugged, especially between stacks such as ac condenser, charge air cooler, hydraulic cooler etc.
Front load garbage trucks need the radiator blown out weekly in 100 degree weather and the cac pulled and cleaned between once a year or more. I was the clean radiator a hole until everyone found out I was serious. Then repeat issues went way down.

I like to hose them out now and then. I need to build something to go onto a hose so that can get between the stacks. On a car or pickup, can easily spray through the layers.

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I found it very important to get all debris possible out dry before wetting it and making it swell. The wash or pressure wash. Also even on pickups sometimes a strong detergent is needed to break down grime. Of course not bending fins during these process is critical. Keeping air or water flow 90 degrees to the face of the core is critical.

Garbage_Mechan said:

One thing that will really throw a fan clutch off is a plugged radiator. Either internally if a cluster of tubes are plugged in the core stopping coolant flow or if airflow through the core is restricted by dirt bugs and debris. The coil in the front or the clutch must be exposed to the actual air temp.

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Garbage_Mechan said:

Over the past 40 years dealing with overheating garbage trucks and landfill equipment I have found that many times we think the core is (externally) clean but on close inspection it actually isn’t. Put a light behind the radiator and be sure you can see light though.
Sometimes pulling a radiator that looked clean it was actually plugged, especially between stacks such as ac condenser, charge air cooler, hydraulic cooler etc.

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Yeah that has crossed my mind too. Roof AC evaporator was so caked with dust, it was freezing and stopping airflow. I was able to literally peel the wet blanket of caked on dust it was so thick. It's hard to hose out due to the air duct for blowing into the living space so I didn't hose it off. The radiator, I will see about hosing off before I leave here. I want to wait until I move to a gravel area for hosing it off, so it doesn't saturate the dirt/grass over where I am normally parked here at this RV park. It has a small (factory?) transmission cooler, in addition to the AC condenser being in front of the radiator.

The condenser is more likely to get filthy in front of the fan, being in front of the radiator and catching everything first.

I use these on my tractors.
http://www.radiatorgenie.com/Radiator_Genie_p/rg1001.htm
They might work on the IDI.
I agree with garbage-Mechanic. I think the cooling issues are not so much the fan clutch but rather a restricted radiator internally or externally.

If you look at fan curves for any cooling fan, they are all about air flow at a specific RPM at a given pressure drop. Raising that pressure drop with a plugged core really does change the fan performance. On a lot of the newest mobile equipment where they run a hydraulically driven fan, they actually use a reversing valve to run the fan backwards on startup and/or occasionally to try to blow debris off of the front face of the cooler. Some designs utilize a square wave on the external fins to make for a lower clogging core, but they do not have the same cooling as the squiggly or perforated fin designs, which by the way are considered to be more prone to clogging. Bottom line is there's no free lunches: the higher clogging fin designs perform better when they are clean, but they are harder to keep clean.

Along with several other earlier comments, I believe a lot of suspect fan clutches probably are victims of plugged radiators. I ran my old IDI without a fan at all for several years, but my cooling system was pretty new and the radiator was super clean.