Dear Tom and Ray:
I have a high-pitched noise coming from the engine of my 2000 Chevy Blazer with 150,000-plus miles. My husband told me it was a belt, and he "oiled it." I'd never heard of that. I thought you tightened or replaced belts. Can you oil them? Also, I haven't told him yet, but the noise is still there today.
Tom: No, you're not supposed to oil belts. When belts get old and dry and cracked, they start to slip. The high-pitched whine you're hearing is your belt slipping.
Ray: Putting oil on the belt may temporarily soften it up a bit and stop the slipping -- or it could grease it up and make it worse!
Tom: But in either case, the effect is temporary. As you've already discovered, the heat and friction will remove the oil in short order -- in your case, in a day.
Ray: There are products, called belt dressings, that are specifically designed to try to milk a little more life out of a dry and worn-out belt. But we don't recommend them. If you have an old, worn-out belt, the best thing to do is replace it.
Tom: So tell your husband we said, "Oil hinges; replace belts." Good luck, Claire.
(Car Talk is a nationally syndicated column by automotive experts (and brothers) Tom and Ray Magliozzi. Write to them at the Car Talk website.)