Changing Serpentine Belts on 1994 Corolla

While I was reading your description of the problem, what I was wondering was, what is the condition of the tensioner? Even on Toyotas, these things go bad over time and make a squealing noise similar to a belt noise.

If you're lucky (or not depending on your POV...) it's the tensioner and will be held in by a couple of bolts. ~$50 and maybe an hour or so of your time.

Might as well replace the belt, too...

I have a 2002 Corolla which I think is the same engine type...? Anyway, I had a weird squeak that was annoying the hell out of me and as hachi just said, it was a bad tensioner/pulley. Once that was replaced the sound went away. I also had them change the belt too.

I thought at one point there was a TSB covering some years and faulty tensioner pulleys but RayO or someone else would know for sure.

Good luck!

There were some TSBs about bad tensioners that Toyota replaced for free. But on the 94 you also want to check belt tension. A loose belt slips and squeal. You also want to make sure the alternator, PS pump, and AC compressore are not seizing on you (bad bearings).

A ~$20 simple gauge from local NAPA store helps:

archive:

I am not a fan of belt dressing because it either masks the underlying cause of the noise or it makes the noise worse, as you have discovered. I have a shelf full of automotive chemicals but do not have belt dressing or any "stop leak in a can" products because I believe that stuff can do more harm than good.

I am pretty sure that the 1994 Corolla does not have a serpentine belt or tensioner pulley. A belt will stretch slightly over time and slip, making noise. You can loosen the alternator and apply a little more tension on the belt. Do not put too much tension on the belt because it can cause premature alternator bearing failure. Go to

Found this out the hard way, didn't I?

Don't feel bad, over-tightening the belt is a common mistake. At least you learned from your mistake, many do not.