[Impureclient]

My OEM belt started squealing at 17k miles so I got a new one and that one later started squealing too a few months in so I put aerospace 303 on it and it
quieted it for about 8-9k miles. So at 26k now it started back in so I changed it again but it is squealing immediately.
The dealer says there's something on the belt but on this new one I degreased all the pulleys until they were 100% grease free and put the belt on.
There is nothing wrong with any bearings, tested them all with the belt off. Dealer said to clean the belt with brake cleaner and that made it squeal worse.
He said it could be the tensioner but it's tight and the belt just barely gets on when installing it so it doesn't seem like it's that.

So I gave in again and sprayed Aerospace 303 on it and it's back to quiet.
Any ideas on what is going on here?