1997 ls400
the car was stored while my daughter was at college. Everything was good for the first 2 weeks and then I got a belt noise. When I spray WD-40 on it, the noise goes away immediately. I had a new belt, idler and tensioner pulleys installed last year. It seems to come from the passenger side. I replaced the tensioner but the noise is still present. I'm looking at the power steering pump/pulley. The pulley runs true. I'm not sure how to proceed...replace pump and or pulley? Try a new belt?

 

I had a serpentine belt go on my car that was 2 years old. Would squeak from the load the a\c put on the belt, otherwise was quiet.

Maybe oil or coolant got onto the belt. That can cause issues on an otherwise brand new belt. Give er' a clean and see what that does. I'm going to assume the tensioner is working correctly since you tried two of them, so it's not loose or nothing, so the tension on the belt is good. If you put water on it and it shuts up, it's not a bearing or anything, so it's either a bad belt or pulley misalignment. Don't forget the alternator, that's also on the passenger side. Is that pulley running true?

 

Thanks for your reply. I replaced the alternator last year and the pulley looks good. I watched all the pulleys and I don't see one that is obviously misaligned. I used a section of hose to try and isolate the sound. Its definitely on the passenger side around the power steering pump. It goes away instantly with WD-40 but comes back in a few moments. The ps pump has a very small leak ( I replaced the ring on the reservoir but it didn't stop it) so I might replace it. I think I'll do the belt first since it's cheaper (and easier).

 

Probably the belt but could be a problem with the tensioner also, you should only be able to twist the belt 90 degrees at the middle of the longest point between two pulleys with 2 fingers.

 

Do you know what brand of belt was used last time? Perhaps that also may be causing issues.

 

I replaced the tensioner and pulley but the noise didn't go away so I'm pretty sure the tensioner isn't the problem.. I'll check the belt brand tomorrow.

 

I replaced the belt and drove it to work and back today. No noise. The old belt was a bando rib-ace. It was replaced last year but I noticed one of the edges was a little frayed. When I stored the car for 8 months I left the plastic under engine guard off. We get a little coastal moisture. I think some of the pulleys got a little rust where they weren't covered by the belt and when I started using the car again the belt got damaged. Or maybe it was just the belt. Anyway, noise is gone and hopefully won't come back.

 

That's great news!! I recently was diagnosing a belt squeak and discovered a helpful tip.

It's similar to the idea where you sprayed WD40 on your belt, however WD40 might leave residue so you can try the following next time -

If you suspect the belt is making the noise, you can apply small amount of water to the ribbed side of the belt while the car is running - if it quiets up you know it is coming from the belt, rather than a pulley.