M1123 A2 - Intermittent sound

[MaverickH1]

When driving the Humvee for a little while, there is the constant buzz sound that I assume is the Cadillac valve for the power steering or something.

Every now and then, that sound will go away and a loud rushing of air sound happens. It sounds like a lot of suction like a massive fan turns on, or somewhat like a deep pitched pressurized torch. It will get louder or quieter with RPM. At 1500 RPM it can barely be heard, at 3000 RPM it's very loud. When the noise stops (it usually lasts about 10 seconds) the power steering buzz comes back.

I want to make sure there's not something going terribly wrong within the engine/transmission/etc.

Is this normal? What the heck is it?

I assume that it's a cooling operation for something, but I can't get it to duplicate often enough with the hood up. It only seems to happen when the vehicle is warmed up.

 

[DainGerous]

Sure it's not just the cooling fan? Goes off at 200-225? deg. Really loud and sucks all the power out of your rig, right? Works as it should.

 

[Retiredwarhorses]

Working as designed...the noise goes away because no more fluid is flowing to the fan clutch. The solenoid closed

 

[Retiredwarhorses]

If you want to reproduce it, unplug the TDM at the 2 prong connector
at the Cadillac valve solenoid,the fan defaults to engaged when unplugged.

 

[TedG]

If you want buzzing sound to go away, wrap the cad valve with belting material to isolate it from the tub.

 

[MaverickH1]

As far as the big sound, are you guys saying it is the main fan just behind the radiators? I've never seen that fan NOT turn. Or is there another fan set under the radiators?

If you want buzzing sound to go away, wrap the cad valve with belting material to isolate it from the tub.

I wrapped it with a cut-up motorcycle inner tube just now and I don't hear it anymore.

 

[Action]

With the hood up, and engine running, unplug the thing next to the washer bottle. You will hear the fan kick in. That should be the same noise you heard previously.

 

[4x4nutz]

Wow...this answered another question I had...lol

 

[TedG]

To be clear with what Action said, not the big plug that connects to the control box, but the little 2 conductor plug going to the black time delay module that is connected to the cadillac valve!

 

[HUMVEE1]

If you want to check the fan clutch without unplugging anything, just turn the steering wheel all the way to the left with the engine running. Fan comes on.