clutch fans are locked to engine

[racing4funn]

Out of the four trucks ive had my hands on, they all have zero movemen. They are locked to do whatever the engine does. Is this the intended design?

 

[Stein12501]

Not an expert but if you mean that the cooling fan does not spin free with the engine off that is correct. Several things have to happen to force the fan clutch to disengage. The power steering pump supplies the pressure and the temp switch has to call for it. The default is engaged. Retiredwarhorse would be able to explain the whole process. Good Luck!!!

 

[mdes0]

My 91 had a stuck fan when I got it. You can tell by the noise it makes over 40ish, sounds like your getting buzzed by a prop plane. I disconnected the line from the solenoid and blew compressed are down the line until the fan moved back and forward, engaged and disengaged. Wrap a rag around the line before you blow air down it, otherwise you'll get a power steering fluid shower like i did.
If the fan moves as it should and it still stays engaged then you have something else wrong up the line like maybe a bad solenoid, check ps fluid level also.

Matt

 

[racing4funn]

I can see why it would default to engaged. Cant have a down vehicle in combat. Strange setup. Opposite of how civilian vehicles work. Anyone else shed some light on the inter workings?

 

[Action]

Inter working? It is hydraulic. It is either on or off.

 

[infidel got me]

I just love guys that can only give smart a## answers.

 

[jerry v]

My 91 had a stuck fan when I got it. You can tell by the noise it makes over 40ish, sounds like your getting buzzed by a prop plane. I disconnected the line from the solenoid and blew compressed are down the line until the fan moved back and forward, engaged and disengaged. Wrap a rag around the line before you blow air down it, otherwise you'll get a power steering fluid shower like i did.
If the fan moves as it should and it still stays engaged then you have something else wrong up the line like maybe a bad solenoid, check ps fluid level also.

Matt

are you talking about removing line from the shutterstat air actuator ? if so top or bottom line coming from shutterstat?

 

[Action]

Here are 3 post about these. There are lots more to read.

http://www.steelsoldiers.com/showthread.php?122936-Fan-stuck-ON&highlight=clutch
http://www.steelsoldiers.com/showthread.php?139072-Humvee-Overheating&highlight=clutch
http://www.steelsoldiers.com/showth...-on-off-before-reaching-temp&highlight=clutch

 

[mdes0]

Follow th eline from the fan, through the shroud to the cadillac valve. Disconnect the line there and apply 100 psi of pressure. This is where I found this info; http://www.steelsoldiers.com/showthr...ghlight=clutch

 

[papakb]

You can remove the hydraulic line that runs between the Kysor-Cadillac solenoid valve (by the windshield washer tank) and the fan bulkhead and pressurize it with air. If the clutch is working you will see it move forward and backwards about 1/4". If that's happening then you need to work further back down the system. A cold engine will have hydraulic pressure applied to the fan clutch to DISENGAGE it. When the engine reaches about 230 degrees the solenoid will DE-ENERGIZE and this will cause the fan clutch to ENGAGE cooling the engine down to about 180 degrees where it will ENERGIZE and DISENGAGE the clutch. After the engine has run for a while a quick check is to feel the solenoid valve and see if it's warm indicating it's energized. After reaching operating temperature you can disconnect the the 4 pin connector going to the time delay module (black module by the solenoid) and you should see the fan move. The sensor that makes this all happen is in the crossover pipe on the top of the engine. The sensor behind the alternator is only for the temp gauge. Hope this helps.

Kurt

 

[Action]

Some guys have mentioned that their fan will not turn with the engine off.
I was just thinking....Would it make a difference if the fan was engaged or not at the time the engine was shut off?
That could be something for one of you to check.

 

[86humv]

Pressure dis-engages it,....so truck off....no turn.
Also, sometimes the inner clutch discs are rusted to the fan inner wall.
That can be fixed with a mallet...just wack it [ silver fan clutch ] and don't hit the nose cone.

 

[Retiredwarhorses]

are you talking about removing line from the shutterstat air actuator ? if so top or bottom line coming from shutterstat?

In the HMMWV world, there is no such thing as a shutter gate....whatever that is.

 

[Retiredwarhorses]

Some guys have mentioned that their fan will not turn with the engine off.
I was just thinking....Would it make a difference if the fan was engaged or not at the time the engine was shut off?
That could be something for one of you to check.

When the engine is off, the fan is locked on, there is no hyd pressure to push it to the unlocked position.
so when the proper temp is reached, the hyd pressure is denied thus letting the clutch engage.
this takes place from 2 items...the thermostatic switch and the time delay module.
cadillac valves rarely fail...the TDM is normally the culprit, followed by the thermostatic switch.

 

[Stein12501]

If we are talking HMMWV then if the engine is Not running the clutch fan is engaged. It needs PS pressure to disengage the fan. Kinda backwards from what you might think. Just like Racing4funn said.

 

[papakb]

No, it won't because the default mode it clutch engaged. Now if you remove the belts you'll be able to move it because your not fighting the crankshaft.

Kurt

 

[74M35A2]

I just love guys that can only give smart a## answers.

Post #4:

http://www.steelsoldiers.com/showthread.php?156328-pic&p=1896053&highlight=#post1896053