WD-40 to fix squeaky belts? Bad idea.

Dear Car Talk

Dear Car Talk | Aug 01, 1995

Dear Tom and Ray:

I am the owner of a 1989 Mercury Grand Marquis. Recently I had all new belts installed at 68,000 miles because I plan to keep the car a while longer. Within a few days, the belts began squealing unmercifully. We returned to our mechanic and he told us there wasn't much we could do. He suggested trying WD-40. This squealing occurs when starting the engine. Do you have a solution?

TOM: Yes. Our solution is a dope slap delivered to the back of your mechanic's head, Earl.

RAY: He did the job wrong, and he should do it again. The belts are too loose. He either put on the wrong belts, he didn't tension them properly, or he damaged one of the tensioners or pulleys during installation.

TOM: And spraying your belts with WD-40 is a lousy idea. The reason they're squealing is because they're slipping. And using something like WD-40 is apt to make them slip even more... even if it cuts down temporarily on the noise. So I'd use that thin, applicator tube that comes with the WD-40 and spray some in to each of your mechanic's ears. Then ask him to shake his head around a little bit to spread it around.

RAY: Don't let him tell you there's nothing he can do, Earl. There IS something. He can start the job over. He wouldn't tolerate the belts squealing if it were his car. And you shouldn't have to accept it in your car either. Good luck.

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