Hissing from the Cadillac valve

[Enforced_Leo44]

The previous owner of my current Humvee installed a "manual" control for the Cadillac valve (his reason was "I don't like when it goes over 180*F", even though as far as I know this engine is supposed to run between 190 and 220*F)
The "manual control" for the valve consists of a switch that overrides the thermal switch and engages/disengages the fan clutch
Now, as the title suggest, when the "manual control" is off, meaning the fan clutch is not engaged, I can hear a pretty distinctive hissing which I suppose comes from the valve, is this something completely normal?
The hissing goes away completely if I engage the fan clutch

 

[rcamacho]

It’s normal.
An insulator between the valve and mount will suppress the noise. I’ve run a Fernco sleeve of the appropriate ID in the past with good results.


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[Enforced_Leo44]

It’s normal.
An insulator between the valve and mount will suppress the noise. I’ve run a Fernco sleeve of the appropriate ID in the past with good results.


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Sounds like a solution to me, will definitely this out, thanks!

 

[Coug]

other options are bicycle inner tube or other soft rubber or plastic. Mine is wrapped in PVC tape.

 

[osteo16]

I used a cut up coozie

 

[Bulldogger]

Hissing is totally normal. I put a folded chunk of motorcycle inner tube around mine. Part of owning a HMMWV. Sometimes hisses, sometimes doesn't.
Welcome to the club!
BDGR

 

[Milcommoguy]

The hissing is normal for the valve.

Clunking, clanking, banging, squeaks and squeals... that's all the other parts.

Music to the HumV owners ears, CAMO

Here's how it works.

 

[RJTM998]

Like others have said cut up inner tube. Ignore the fluid leak that was one of the attachment points not screwed down tight enough and now fixed.