Tightening belt - bearing problems?

[Kyngfish]

Hi,

So lately, when it's wet or on startup, I get a 10-15 second squeal out of the AC side of the engine compartment. Sure enough, last time it happened I killed the AC fan and the squeal went away, so I think I've isolated the issue.

Today, as I was passing someone at low speed, a downshift created the same squeal, I assume the sudden increase in speed created some belt slippage.

That said, the belt seems fairly tight, and moreover, looks pretty new (new car to me). I was going to go in to tighten the belt, but I have a few questions:

• How tight is tight enough? How can I tell? I want to avoid damaging bearings.
• Could the problem be anything else, given the symptoms described? I don't SEE any leaks that could be dropping some kind of fluid on the belt and creating slippage.

 

[thegipper]

I believe you want about 1/4" of play on the PS belt and AC belt. The alt belt should have about 1/2" of play.

I would purchase all new belts (get good ones) and replace them all. I just did mine and it took maybe an hour to do them all. There are a few write ups and videos on youtube that should help you.

My belts actually didn't look that bad at all but I would get the occasional squeal on cold morning start ups. I replaced all of the belts and doesn't make any noise anymore.

 

[LittleCaesar]

Considering you live in one of the most humid places in the states, replace the belts. Clean the pulleys with a brass brush if need be:
How to: Change Drive Belts 3.4 L 5VZ-FE - YotaTech Forums

 

[Kyngfish]

Ok

Thanks for the input.

I guess my main question is, how can I be sure it's the belt and not the pulley?

 

[TheDurk]

Thanks for the input.

I guess my main question is, how can I be sure it's the belt and not the pulley?

I don't think there is a way other than the noise goes away when you change the belt. You might be able to feel an irregularity in the pulley once you have the belt off. But at that point, might as well change it as PM while you fix the pulley, too.

If you knew the age of the belt, you could rule it out. But the factory belts I took off at 120k (I am original owner and sole wrench since Day 1) LOOKED like they were not old at all. Still, the P/S belt had started squealing and no reasonable level of tightness would make it stop. Luckily, I did the timing belt at the same time so the fix was easy.

Speaking of which, when was your timing belt done?

 

[nobb]

Tighten the tensioner and that should fix it. I know there's an exact spec on belt tightness but you'll need to jig up something to measure deflection and force.

Bearings don't just suddenly fail prematurely from slightly over tightening the belt. There's usually quite a large amount of safety factor in bearing design for loading and you'd have to really screw up the install to shorten the life considerably.

The fan clutch bearing is quite beefy and gives plenty of notice before it fails. Would also be a good idea to replace the AC tensioner pulley because at this age it's probably starting to go bad.

 

[Kyngfish]

Pulley

I see the idler pulley, is there a different part number for tensioner pulley? or same thing.