Strange humming noise.

[redjmp]

It is constant in level increasing in pitch only slightly when revving. Only shows up in hot weather after restarting a hot engine.
Goes away after driving for 5 or 10 minutes.
It is the same pitch as the " HOO HOO's" in the Stones' "Sympathy For The Devil"

 

[dangerranger911]

have you checked the a/c clutch bearings or the idler pulley and tensioner also look for a vacuum leak.

 

[redjmp]

Well I thought it might be the A/C but I disconnected the plug that engages the clutch so it does not even run.

It seem this noise is comming from inside the air cleaner.
I opened it and it is for sure comming from from after the air filter.After the big rubber boot.
In fact it is comming from a hole just above the throttle valve.
Is this the IAC?

What can be wrong with it? Does it just need cleaning?

 

[Bob Ayers]

The IAC valve can make a humming noise. You can try cleaning it, but more than likely it will need to be replaced.

 

[yorgy]

Possible answer

Hey I've had that sound forever . I remember somebody telling me that it's the fan clutch . Don't know if it's true or not but it sounds reasonable. Good luck yorgy

 

[nismotunedgtr]

Had the sound in an Explorer and it was the Alternator.

 

[Frank The Tank]

Your CD player on loop? skipping sympathy for the devil over and over by chance?

Your welcome, I just fixed your truck, now for the consultants fee.

Frank

 

[BrokeRecord]

Replace the IAC. It gums up and has a tiny air gap that hums when vacum goes thru, after warming up. Very embarrassing when in public.

 

[sniper141]

I usually just look down!!! HAHAHAHA!