Fan clutch stuck? The tool I used to fix.

[Waterloo]

I know more than a few of you know how to do this. This is my first time, and thankfully it worked. Just being long winded for the guys like myself that have read about using air to release a stuck fan clutch, have no clue on how, but want to know how. Also, some of the tools that make it a fairly easy and straight forward job.

Drove the truck yesterday, first time in months... The darn fan clutch was stuck, as in engaged and would not turn off. The fan clutch is a year old. My AC was blowing ice cold, so I ruled out low refrigerant and or a bad high pressure switch. No air leaks, solenoid appeared to be working when I used the switch on the dash, you could hear it working its magic... Except, it couldn't, as the fan was not disengaging.

Here is my fan clutch and how it works, to help better understand what I was doing, with photos. The fan clutch uses air pressure to stop the fan from turning. When air is tuned off to the fan clutch, the fan starts spinning. This link is very good at explaining this. https://kit-masters.com/tech-tips-auto-lock/

The fan override switch on the dash, at least in my truck, engages the fan. If everything is working normally, when you want the fan to go on, or engage, you turn that switch on. I would hit the switch to on, hear the air release at the solenoid. I then turned the switch off, pressurizing the fan clutch, except fan was still engaged. Not good.

Well, I tapped on the fan clutch with a small brass hammer, nothing. I needed air. I called up to FleetPride and spoke with Jeff. He told me to come on up, he had the fittings I needed. Sure enough, he had a push pull fitting that adapted to a male air compressor fitting, 5 feet of 1/4" air line and a 1/4" push pull union to join my fan clutch air line up near the firewall. Perfect! All cost around $15

I had to pull the air cleaner on the ProStar to get to the fan clutch air solenoid. I then went and drained the air tanks on the truck.

I broke out my quick release pliers to disconnect the two airlines, it would not have been possible without these pliers, as I could barely even get my one had to the actual fitting. If you do not have these quick release pliers and work on your truck, you need to seriously consider getting this kit. It has saved my bacon more than a few times, and has worked flawlessly every time I have used. https://amzn.to/2MeIqK0

I disconnected the two airlines to the solenoid, there is an inlet side from the firewall, and the outlet side going to the fan clutch. I then removed and inspected the solenoid, it looked good, wiring was still intact and not brittle, plug intact at harness and solenoid.

I hooked up my new air line adapter to the air line that heads up front to the actual fan pulley using that 1/4" push pull union fitting I just picked up. I plugged the other end of the 1/4' air line into my little Lowes air compressor and turned it on to build pressure.

I just let her gently build pressure while gently tapping on the fan clutch body with a small brass hammer. Right around 90 psi the fan clutch popped! it was disengaged!

Here is the brass hammer I used, 16 oz fit in there nicely. https://amzn.to/2HLB1xD

I then tested the solenoid, I wanted to be sure that was not the problem or had issues. I plugged in the solenoid to the motor harness. I then used the 1/4" push pull union to connect to the inlet air line going into the solenoid to my shop air compressor. I started the motor, and turned the fan override switch on and off. I could hear the whistle of air when I turned the switch off, and it stopped whistling when switch was turned on. Everything was working.

Buttoned everything up, gave it a test run, everything was working as it should. I guess we had a little lot rot in the fan clutch from sitting. This was a cheap diagnostic test with some inexpensive fittings and air line. I will add again, I highly doubt I would have been able to remove these airlines without those disconnect pliers, I can darn near guarantee that.

Here is what Jeff at FleetPride sold me.



Here is your fan clutch solenoid... At least on a ProStar.