My drive belt has been making an annoying squealing sound for the past few weeks. The belt appears to be in good condition (no cracks in ribs) and the tensioner appears to be fine as well (notch is in middle of indicator markings). I sprayed some contact cleaner on the back of the belt with the engine running and the noise got quieter for a split second. Then I took some tension off the belt by releasing the tensioner a little and the squealing completely went away. So, the squealing only occurs with the belt under tension. Apparently the squealing is being caused by the back of the belt rubbing against the tensioner pulley. Should a new belt take care of the issue? I already ordered a new belt and the tensioner, but will return the tensionser if the belt fixes the issue. Was just trying to see if anyone else has experienced this and what the cause/solution was. BTW, I was able to spin the tensioner pulley by hand so I don't think that is the issue. And the noise goes away when I rev the engine.

 

I had the same issue on mine. I went through three different belts, all different brands, before I got a recommendation from a neighbor to try the Goodyear Gatorback belt. I've had it on there for nearly 40K miles now and it's dead silent. It has a different design than a standard drive belt which is supposed to help reduce noise. I'd say give that a try before you go replacing too many components.

 

Did you ever try the Bando Belt?

There was a TSB issued back in 2011 for squealing on cold starts and idle, but it says it's for the 2007 and 2008 TL. It involves replacing the AC compressor bolts and the drivebelt with the Bando brand.

 

Yes, I tried Bando, Continental and Duralast (Autozone). All of them were quiet to begin with but began squealing after a few thousand miles.

Using the Gatorback may just be a bandaid covering up the actual cause for the squeal. Either way, it works. And whatever the root problem is, I don't think it's damaging anything.

 

Failing bearing(s) in an alternator can cause a belt to sequel during idle.
It's not the most likely cause but it's possible.
Next time you have the belt removed check that the alternator turns freely.

The most likely cause is the bearing in the tensioner pulley.
I change the tensioner pulley every 105k miles with the timing belt.
I don't change the tensioner assembly; just the pulley.
(FYI; the bolt for the wheel has left handed threads so reverse the direction to remove and tighten bolt).

 

The alternator is brand new, and the noise went away when I took some load off the belt, so I'm thinking it's either the belt or the tensioner pulley. I'll be replacing both this weekend and will post back with the result.

Thanks for the tip!

Can you change the pulley with the tensioner in situ?

 

A good test is to place just a couple drops of water on the belt while idling and see if the noise goes away. If it does, then it's almost certainly the belt. The water gives that little bit of lubrication which will make the noise go away (very temporarily of course). If the noise persists however, then it's another component like a bearing or something.

 

I sprayed contact cleaner on the back of the belt and the sound changed, so I'm assuming it is the belt. I'm going to go ahead and replace the tensioner pulley anyhow for good measure. It has 92,000 miles on it.