I've been hearing this lately when warmed up and idle...

060.flv video by iplayloudly - Photobucket

It doesn't do it when cold. You can hear compressor kick on and the noise speeds up a little, but I don't think it has anything to do with the compressor. I hear the noise if the air is on or not.

I thought it was a pulley but it sounds slower than the speed of the serpentine belt... I hope its not a timing belt pulley.

The truck seems to run fine otherwise.

 

its hard to tell from the video but it sounds like the serpentine belt.

 

Well I figured out its not the belt or any of the pulleys. I took the belt off completely and ran it for a minute, and the sound was still there. I guess its coming from inside the engine. Probably not a good thing. :-/

 

You ran the engine without the belt?

 

What! did you really run it without the belt?

 

yeah, its not going to hurt anything to do that, as long as you dont move the truck from where its sitting or let it run for too long.

 

So it doesn't matter if the cam is out of time with everything else? I've always been told that the timing was critical so you wouldn't smash pistons and valves and the other bits and pieces together.

 

pulling the serp belt wont mess up the timing. thats run off of a seperate chain.

 

i didnt take the timing belt off, just the serpentine belt.