I've read numerous threads concerning belt noise and pulley alignment, but I haven't seen an answer to my question. First the background:

I have a 2003 MCS w/ 55k miles, car runs great. I put on a Alta version 1 15% pulley (changed to a new NAPA stock length belt) and a Voltage CAI at the same time, both great products btw. Before dropping car from jackstands we cranked the car and it was as quiet as stock.

3 days later I noticed a belt squeak when you first start the car, it got worse as time went on. I changed the belt to the NAPA 535 version and checked the slide on the belt tensioner. The tensioner showed hole and half visible. Cranked the car and it was fine, no squeal.

It's been 4 days now and the belt squeal is back, I checked the tensioner slide and it shows a full hole.

I followed the directions about bottomng the collar on the shaft and torqued the bolts as stated. Not sure if any of the other parts run by the belt could be going out or the pulley is just not lined up right. The squeal does go away after a bit. Any suggestions would be appreciated. Thanks

Patrick

 

Sounds like it might be a bad tensioner damper (the little shock absorber on the tensioner).

Check the tensioner for oil and dirt on the damper shaft. If it is bad, the only way to replace it is to replace the entire tensioner assembly.

 

I put an Alta 15% pulley on years ago on my '03 and had no squeal with the stock belt. Last spring I installed a shorter belt recommended by DT, and it didn't squeak at all until about a week later. Since then it squeaked at startup and then disappeared after a few minutes. Just last week it stopped squeaking. I don't think mine is misaligned, so maybe the tensioner is to blame. But until I have a sense that something is actually suffering I'm not going to change the tensioner. Good luck!

 

You can tell if the damper is bad by the amount of oil/dirt on the shaft. You can check this with a flashlight. Best to replace asap if it is bad because if the tensioner itself goes it could damage the crank pulley and get real expensive to fix.

 

Just say it is the damper causing the problem, how is it causing it? I thought the spring was the major item providing the tension for the belt. Excuse the newbness.

Patrick

 

my '03 did the same thing for a while, what i did, and it worked, (yes i know it sounds like a bad idea) was i poured a little (don't pour alot) water on the belt right where the alternator is (easy to pour it there) while it was running. the belt slipped for a half second, then i was dry and quiet. I ended up doing this for three start ups, and now it's quiet every time.

 

The tensioner has a big spring to keep the belt tight against the pulleys, but it also has a small damper (shock absorber) to keep the spring from bouncing off of the belt. The bouncing can cause strange noises.

The water trick works good to remove belt residue from the pulleys which can cause some squeaking. Oh and happy first post Bigt

 

thanks, hope it worked

 

Update on belt noise problem:

I checked the damper and it appeared to be clean. As I was looking at the damper I noticed the belt was not riding in the same area on the idler pulley as the original one was. It look as if the belt was riding about a 1/4" towards the passenger side of the car, it was easy to see because the old belt had worn off the paint on the pulley.

So I got the car down to where I could see the SC pulley and the crankshaft pulley without any obstructions. By lining up the edge of the engine block and the pulleys I could see the SC pulley is not lined up with the crank pulley, it's about 1/4" off. Now two people verified that I when I put the collar on for the pulley that I bottomed it out on the shaft as instructed. I'm in the process of taking it back off to confirm.

Anyone run into this problem before? Maybe I need to machine a little off the collar to get it to line up? Suggestions please Thanks for the replys so far.