[lowrydr310]

My belt started squealing after cleaning my engine compartment last week. I tried the trick spraying the belt with water and the noise went away, but came back soon after. I applied belt dressing which initially made the sound go away, but as soon as the solvent evaporated the sound is even worse now, a loud screeching sound that is sometimes constant but sometimes intermittent with each revolution of the belt.

The sound is very loud now and it is difficult to tell if it's a bad bearing or just the belt, but it is definitely coming from the tensioner assembly - either the bearing on one of the pulleys or the belt screeching on those pulleys. Spraying water on the belt directly makes the sound go away for a bit but it comes back soon after. It's just this awful intermittent screeching sound that almost sounds like a bad bearing and I'm paranoid.

I was supposed to get an alignment this week but I can't drive it like this knowing the catastrophe that could happen if it's a pulley bearing that siezes up and snaps the belt. It's a pain to have to reschedule the alignment, but I ordered a new tensioner, pulleys, and belt.

When I have the belt off, what can I use to clean all the pulleys that I'm not replacing?

I also ordered the URO 'upgraded' aluminum power steering pulley after reading how they can fail, but my power steering pulley looks fine. There's also a good 1/2" or more of clearance between the pulley and subframe even with aged engine mounts, so I'm not too worried about that. Should I be? I may just hold onto the new aluminum pulley and not install it yet.

[spazzz]

I had my belt/tensioner replaced and it was making a bad chirping noise awhile later.
I saw a video on You Tube where the guy sprayed his belt liberally with Aerospace 303.

So I gave it a shot and a year later still no noise. Goofy but true

[jsunma]

You don't say anything about how long it's been since you last replace the belt and tensioner. So, rather than assuming something worse than might be the case, just replace the belt and tensioner (if it's been 50K or more since the last time) and see how that works.

If there's still a terrible noise, then you can proceed to troubleshoot from that point.

[lowrydr310]

Originally Posted by jsunma

You don't say anything about how long it's been since you last replace the belt and tensioner. So, rather than assuming something worse than might be the case, just replace the belt and tensioner (if it's been 50K or more since the last time) and see how that works.

If there's still a terrible noise, then you can proceed to troubleshoot from that point.

That's exactly why I already ordered a new tensioner, belt, and pulleys. I just got the car. a few weeks ago and I have some service records, but nothing for the belt/tensioner. They're definitely not original but who knows when they were last replaced.

I want to know how to clean the crank, AC, alternator. and PS pump pulleys while I have the belt off.

[lowrydr310]

Originally Posted by spazzz

I had my belt/tensioner replaced and it was making a bad chirping noise awhile later.
I saw a video on You Tube where the guy sprayed his belt liberally with Aerospace 303.

So I gave it a shot and a year later still no noise. Goofy but true

Holy crap, you're right! Why isn't this solution promoted more often? I have a new belt, idler pulleys, and tensioner ordered so I will be replacing them soon but I figured this 303 trick was worth a shot since I have a bottle of it. I just sprayed the end of a paintbrush and lightly applied it to the back of the belt while the engine was running and it instantly silenced it and hasn't returned yet today!

My 330i has a mild belt squeal for a second or two when I start it every morning, despite the tensioner only being two years old and 20K miles. I put some 303 on the back of that belt, so I'll find out tomorrow but I'm guessing that is fixed too.

[spazzz]

Man, I put it on stream and applied liberally as they say.....every pulley area, I had a little puddle on the undertray when I was done. Yeah, I kinda said fuc these chirping birds.

[san40k]

My belt "grinding" noises are gone after I replaced alternator pulley. It was locked/stuck. This helped me understand whats' going on:

Requires a special tool to remove/install: https://www.fcpeuro.com/products/alt...er-lisle-57650