Hi guys! My new-to-me '07 Overland Cherokee (5.7 Hemi) has a strange sound that it makes at random times. Mostly heard within a few seconds after starting it. The only way I know how to describe it is that it sounds like an extra / auxiliary fan or something blowing under the hood. It is fairly loud at first, and after 4-5 seconds it slowly winds down and stops.

Engine RPMs are not related to this sound and revving the engine has no effect on it.

Is this normal? And if so ... WHAT is this? It almost sounds like a small air compressor coming up to pressure.

Any thoughts would be appreciated.

 

Could be the cooling fan clutch engaging when it's cold.

 

I didn't mention ...... It only does this when it is at operating temperature. Never noticed it when the engine is cold.

 

most likley the clutch fan, and if it is doing it at warmed up temp, it is probly ok.

 

Normal for a hemi. THe fan clutch will heat soak when the engine sits after running and will start really moving air for a bit until it cools down. My 04 and 06 hemis do the same thing.

 

THANK YOU SIR!

That puts my mind at ease.