Constant running fan.

[newhmmwvguy]

Caddy valve runs very hot about less than 10 mins, if i unplug the caddy valve of tdm, fan runs all the time, dont see it move forward at all. I will try to put the air in the hose at the end of caddy valve. Do i need to fill the hose with hydrolic fluid?

 

[Bravojmc]

Caddy valve runs very hot about less than 10 mins, if i unplug the caddy valve of tdm, fan runs all the time, dont see it move forward at all. I will try to put the air in the hose at the end of caddy valve. Do i need to fill the hose with hydrolic fluid?

When you take the hose off the caddy valve , the hose will have enough fluid in it to perform the duty.
when you put air to the line you should see the fan move forward.

 

[anthkey]

Need some help here....
2 years ago, fan wot working....replaced it all, solenoid , fan clutch switch and temp censer... worked fine.(till now).
fan was coming on fine, till a hair pin turn to my street, and the system blew the hose on the solenoid...
cleaned everything up.. refilled (got all the air out), and now fan wont come on? but it kicks on when turn steering to way hard right or hard left??
any input ????

 

[frank8003]

It is a fail safe thingie?
Ya know ,that is what the Airborne is for ......................
They just drop in least expected and make problems go away.

 

[newhmmwvguy]

Check power steering fluid.

Need some help here....
2 years ago, fan wot working....replaced it all, solenoid , fan clutch switch and temp censer... worked fine.(till now).
fan was coming on fine, till a hair pin turn to my street, and the system blew the hose on the solenoid...
cleaned everything up.. refilled (got all the air out), and now fan wont come on? but it kicks on when turn steering to way hard right or hard left??
any input ????

Check power steering fluid, put compress air at the solenoid, bleed it and fill it up, then all works

 

[papakb]

Have any of you gone through the cooling system troubleshooting flow chart in the TM9-2320-280-20-1 manual? Starting on page 2-164 you'll find a flow chart that walks you through the steps to diagnose problems with your cooling system. It's written so the average mechanic can follow the steps.

The HMMWV cooling system is one of the more convoluted systems in the HMMWV and operates backwards from the way you think it should. When the system is operating correctly with everything plugged in the pressure from the power steering pump passes through the Cadillac valve and keeps the fan clutch DISengaged and allows the fan to freewheel. It's hard to tell if it's engaged or disengaged but the racket the fans makes when it's engaged is your best indication. Visually the fan will move forwards and backwards about 1/4" when it's working right. This can be verified by applying and removing 90 psi air pressure to the clutch via the line the runs from the Cadillac valve to the feedthru on the fan shroud. When the temp switch (in the crossover manifold) tells the system that it's reached about 230 degrees it turns the Cadillac valve OFF, the pressure to the fan clutch drops to zero and the fan engages. This is done as a fail safe mode so that by unplugging the time delay module or the connection to the solenoid the fan engages and runs all the time. The sensor behind the alternator is the sensor for the temperature gauge only and has nothing to do with the fan operation.

Sticky Kysor-Cadillac valves can be cleaned, the solenoid can be replaced with another 24v solenoid if it fails, and the clutch friction collar and O-rings are available in overhaul kits.

Hope this helps to understand the way the cooling works.

 

[JAG]

Wasn't really specified which hose to push compressed air through, on the cad. valve side. So I tried all three hoses.

I didn't see the fan clutch move at all - does that mean the fan clutch is stuck? If so, what is needed to get the fan clutch to become unstuck? A rebuild?

 

[papakb]

This can be verified by applying and removing 90 psi air pressure to the clutch via the line the runs from the Cadillac valve to the feedthru on the fan shroud

 

[Milcommoguy]

Not to be confused with turning or not, the fan will always spin. When it is locked up, you will know it by LOTS of air movement, with a roar of noise, sucking engine power. Probably all ready knew that.

Cadillac valve does run warm due to warm / hot power steering fluid flowing thru it and the solenoid coil gets a bit warm too, as it is for the most part always energized. Good chance clutch is gummed up. Apply air per PAPAKB.

Make up some Rude Goldberg air connections applying air. (air fitting to your hose for easy air, on air off control) Engine OFF and see if you can free it up. Apply air AND easy on turning the blades as to not snap one off and a light tapping of hammer on ring between fan and pulley. Maybe able to get it to free up. Had the same problem here and after 10 minutes of air on and off, tap tap tap, turn turn turn and some WD-40 on anything that moves, repeat... it came to life. When you get it really working you will see the fan move back and forth on the spinner assembly about +/- 3/16 of an inch with on /off air test.

Put it all back together and test with a cold engine and plug/unplug Cadillac valve electrical plug. Hold on to your cover when it kicks in.

Engine OFF. Never ON when your fingers are in there. Good luck, CAMO