Is it always bad news when your oil light comes on?
Is it always bad news when your oil light comes on? I have a 1986 Audi 4000, and when the rpm goes above 2,500, the oil light comes on along with a buzzer. I'm scared to take it to a mechanic for fear of what he might tell me. -- Kelly
TOM: Hey, Kelly, that's MY approach to going to the doctor. When something hurts, I avoid the doctor so I won't know anything's wrong. By the way, my wife cites this as a prime example of my unfathomable stupidity.
RAY: And trust me, she has many examples from which to choose. The answer to your first question is yes, Kelly, it IS always bad news when your oil light comes on. The only question is "how bad"?
TOM: And the possibilities range from "not that bad at all" to "what are the rates on new-car loans?" Fortunately, I think you're at the mild end of the scale.
RAY: This car has an unusual oil warning system. Like most cars, the light comes on if your oil pressure is too low. But unlike other cars, it also comes on if your oil pressure is too high. And the fact that the light comes on only above 2,500 rpm tells me it's more likely that "high pressure" is the problem.
TOM: That's usually pretty easy to fix, but you absolutely should go to a mechanic, Kelly. If you keep driving around with high oil pressure, your oil-filter gasket can easily blow out, and then you'd lose all of your oil.
RAY: And then the oil light would come on for the other reason -- because you'll have low, or no, oil pressure.
TOM: So have a mechanic put a pressure gauge on the engine, rev it up to 2,500 rpm and see what your oil pressure actually is. If the gauge reading is normal, you probably just have a bad sensor. And replacing the "high oil pressure" sensor should fix it. And that's cheap.
RAY: If the pressure actually IS high, you probably need a new oil-pressure relief valve. But even then, you're not talking about a second mortgage here. So get it fixed, Kelly.
How can you tell if a used car is in good condition -- or even OK, for that matter? Find out by ordering Tom and Ray's pamphlet "How to Buy a Great Used Car: Things That Detroit and Tokyo Don't Want You to Know." Send $3 and a stamped (55 cents), self-addressed, No. 10 envelope to Used Car, PO Box 536475, Orlando, FL 32853-6475.
Got a question about cars? Write to Click and Clack in care of this newspaper, or e-mail them by visiting the Car Talk section of cars.com on the World Wide Web.
?(C) 2001 by Tom and Ray Magliozzi and Doug Berman
Distributed by King Features Syndicate, Inc.