Belt Squealing

I have a 2010 Toyota Corolla S and recently I had the serpentine belt replaced. Now it makes a loud squealing sound when I start it, but goes away when I go in reverse. Also it doesn’t do this every time I start it, just when it’s cold. Anyone know what this could be?

Go back to the shop and have them figure it out. In my experience, it could be a bad belt ,pulley or tentioner.The squeal could also be the result of an incorrect installation.

I took it back and they said everything was fine, obviously they don’t want to take responsibility. Guess I’ll have to get corporate involved

Ask a few more places.Obviously this guy doesn’t like comebacks.

By corporate I guess that means this is a franchise operation so corporate might not even get involved . If you asked for a new belt and did not request other work they will want to charge for a diagnostic to find the squeal . It might just be simpler to have another shop look at this vehicle. Of course they will need it over night so they can start it cold.

possible causes:

-incorrect belt (to loose)
-bad tensioner- these do wear out, and I have begun to replace them when I put a new belt on. Not always necessary at that moment, but saves me a lot of issues later. I have had some in the past go bad shortly after new belt install because of the strain on the tensioner during belt install
-Some other accessory going bad, causing belt slippage. Other accessories could include: Alternator, power steering pump, air pump, idler pulley, a/c compressor

-something else. It could be a complete coincidence that something else is squealing now that the belt has been replaced. BUT, your description of it going away when the engine warms up or temperature is warm sounds like a loose belt in my experience.
if this shop won’t help, find another that will.

The belt isn’t tight enough, it needs to be adjusted.