HMMWV help

[usmc81301]

I start up the HMMWV and everything is fine. The problem comes when it gets hot. When I drive it down the road for a while and then come to a stop I hear a grinding type noise that starts and stops. It happens for a brief moment after I hit the gas pedal and then appears to stop. I cant hear it over the engine anyways. That's the best I can explain the sound. All fluids are fine. Does anyone have any ideas what this could be? I did record the sound if any one thinks that would help.

 

[emmado22]

Is it the fan clutch kicking on and hitting the fan shroud? Does yours have the metal retainer bracket that connects the rad to the fan clutch? It's part #3 in the pic...

 

[usmc81301]

I am not sure if it is hitting that part. I don't hear noise from that area when I have the hood open. Would it be doing that off and on? It makes the noise when it has been run kinda hard and seems to stop when it has had a chance to run at slower speeds. I will have to check that part out.

 

[emmado22]

With the engine running, unhook the fan clutch wire.. That will make the fan clutch engage.. If the noise happens when you unhook the wire, then goes away when you hook the wire back up, you have a fan clutch issue.. It culd be as simple as thats the noise that the fan clutch makes when it's opperating normally (the first time the clutch engaged when I was driving a HMMWV for the first time scared the crap out of me, and I went back to the Motorpool.. I explained what happened, he did the fan clutch wire unhook, and said "is that what it sounded like?.. I said yes, and he tells me "dont worry about it LT, it's supposed to do that" or the noise could be something worse going on. Have you checked your Power Steering fluid? The PS system is part of the system that makes the fan clutch engage. If it's low on fluid, thats not good. Dextron III is what it takes.

 

[hummer4x4guy]

Does it sound like its coming from under you? Check the bolts between the back of the engine and the tranny...if those come loose and start to seperate you will bust you flexplate and once it breaks it will make a terrible noise...not that I would know tho..
Joel