Fan engagement - Need your help again

[kcpstudio]

Hi guys,

i need some advice on the fan engagement and disengagement. Basically, how much louder when it kicks in.

Yesterday I replaced the cadillac valve. I ran a complete diagnostic on the entire system from the coolant sensor to the time delay to the valve to the clutch. Everything passed. I did have a bitch of a time bleeding and tightening belts, but all is good.

1. With the engine not running, there is no way of spinning the fan. It’s locked. So, we’re good there.

2. When I run the engine and prior to it hitting temp to trip the engagement, the fan spins freely. I can stop the blades using soft rubber and then hold that with my hand and keep the blades from spinning. So, we’re good there.

3. If I disconnect the time delay, the fan will engage. I can visually see the blades flex maybe a half and inch. If I connect the time delay, it disengages.

Here’s my question, there’s only a tiny bit of sound increase when engaged. It doesn’t sound like any turbine as some have described. But I know it’s engaging. Now, maybe that’s because I’m only manually tripping it at idle.

Anyway, can someone put this to rest for me? The system is running per the TM but I’ve got people saying it should sound significantly louder when engaged.

 

[Action]

Use the hand throttle and set the idle faster, then get out and pull the plug. I would think it gets louder with more RPM. You will definitely know when it kicks in if you are out driving.

 

[Dock Rocker]

If I remember correctly you can certainly tell when the fan comes on at idle but it’s not the end of the world sound.

Now at highway speeds it sounds like everything in the front is about to fly through the doghouse. I so wish someone had told me about that. I seriously pulled over because I thought it had eaten itself.


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[kcpstudio]

Cheers... ACTION! Yup, that was it. I know it was a dumb question but, the fan never worked since I had it. It was always engaged. So, with the new valve installed and the fan working, I needed to understand what people were saying about it kicking in like a jet engine. Overseas, we kept the fans engaged all the time. So everything sounded fine to me. Well, now I know. Lol Thanks again, Bro!

Use the hand throttle and set the idle faster, then get out and pull the plug. I would think it gets louder with more RPM. You will definitely know when it kicks in if you are out driving.

 

[papakb]

Just take the truck out and drive it around until it gets hot. If it feels like an elephant just landed in the bed when the fan kicks in it's working! LOL

 

[Milcommoguy]

STOP, LOOK and Listen. What is the attraction to try and stop a moving fan with the engine running? Did I read that right? Test step number one " locked up with engine off" GOOD. Step number two, BAD IDEA! KEEP YOUR HANDS and RUBBER GOODIEs out of there.

Step three, valid. Cadillac valve "de-energized" by removing plug from module, removes power steering pump pressure, engaging clutch. At idle it not going to be a big show. Fan locks up and moves some air. This is what happens when system (good module / sender / wiring) when temperature reaches 230 +/-. Put it back together, take it for a spin. Keep you fingers on the steering wheel. Find a hill and under load at 50 MPH and engine temp pushing around 230+/- you will know when fan lock kicks in. Screech, bark, thunk and the fan blowing like a hurricane, sucking 12 horse power. Twenty second of so, fan should disengage, you get a boost of power, temperature around 190 degrees. Another test. Back on that hill, with fan engaged, put the pedal to the metal / floor and fan should dis-engage and you should get a boost of power from the power robbing fan. Don't confuse this with a transmission down shift. This is the Hummwv cooling system and it may start and stop at any time.

Better test search air hose method, engine off. Safety First.

CAM

86 Helmet Top

 

[Action]

If i ceiling fan is blowing down on high and shut off, you can stop it with your finger. As long as finger doesnt hit the leading edge of the blade, you will not get hurt. The blade will push away from the finger and slow.
I dont reccommend doing it in the humvee fan, but i have done it, too.