I replaced my serpentine belt on Sunday. The last two days I am hearing a noise after I start my truck and at aproximately the same time the AC compressor kicks in. It sounds A LOT like an anti-lock brake system when it gets activated but its coming from the area where the Compressor and Tensioner are. It is NOT a squeal or chirp. I ONLY hear it after initially starting the truck. Any ideas?
-Tim

 

I know that noise, my truck makes it too but its an 06. I have never given it a second thought though since it only does it in startup when the engine is cold. I would like input on what the noise is. Has done it for the past 50k miles and no engine problems to speak of.

 

I've been playing with when I turn on the AC, if I start the truck and let it run for 3-4 minutes I won't hear the noise. It didn't start till I put on a new Gatorback belt (replaced an existing gatorback).

I'm thinking Tensioner. The question is, how do you diagnose it?

-Tim

 

Open the hood while the truck is running and look at the tensioner and AC pulley. If either are unstable, you have found your problem. If they look ok, you could take off the belt and see how loose the 2 pulleys feel.

Good luck!

Dave

 

I think its the AC belt tensioner. Have you encountered this before or this is the first it happened to your truck?

 

Ever use a mechanic's stethoscope? You can pin point all kinds of trouble with one of those. And, they're less than $20.oo
You'll use it for the rest of your life.

 

Well I think I found the problem in December of 09'.
I made a trip to Albuqurqe, NM to pick up a couple of canoes. The first day back to work I dropped my serpintine belt...... the tensioner had completly failed at some point on the trip and eventually ate through the belt. So 3 months before it failed, it started rattleing...

ON THAT NOTE
I spent most of the morning putting a new roller on the tensioner....
In two months just put a new tensioner assembley on the truck and it took 30 minutes.

I'll NEVER put just a roller on again...

 

My method of tracking down a failing pulley bearing has worked every time. Just use a spray bottle to squirt some water on the bearing side of the pulley with the engine idling, the noise will stop or change pitch when you hit the right one.