Was on the way to go camping pulling the 5th wheel after work today. About 15 to 20 miles into the trip we pull a small hill that is part of the local belt route here, when the wife and I start to hear this noise. At first just thought it was the clutch fan but it sounded like it was coming from inside the dash. We got a little farther up another hill and it is still there loud as ever, so we pull off the side of the road to listen to it.

The noise seems to be affected by the engine RPM's, sitting there with it park it seemed to get louder between 2200 and 2400 RPM's.

We sat there for about fifteen minutes pondering whether to go on, as we still had quite abit of hills to pull, while sitting the truck cooled down and the noise seem to fade but not go away entirely. We turned around and fiqured better safe then sorry.

Now I am sitting home pissed that I am not camping.



Long winded I know.

Any thoughts or ideas what the hell it is???????



Truck info:

'07 lbz with banks intake, 4'' turbo back exhaust, edge evolution......set on tow mode

sounds like an idler pulley, they go out pretty often.

thats what i was going to guess also, Just had to replace one on my 06 with 113k. Only $22 out the door from the dealership.

OK, thanks.
Of course this morning I can't get it to do it. (shaking head)

Its easiest to go ahead and replace both idler pulleys and the serpantine belt at the same time, save yourself some trouble later, and be sure to check the tensioner.