Dear Tom and Ray:

I change my own oil and filter in my cars every 3,000 miles. I try to buy the oil and filters when they're on sale to economize. I have always heard that once you start to use an oil you should never change brands because different oils contain different additives. Is this an old wives' tale or what? -- Dan

Tom: Let me assure you, Dan, this is complete and utter hooey. You can mix and match any brands of oil you like in your engine, except perhaps Filippo Berio Extra Virgin Olive Oil and A&P cod liver medium grade.

Ray: As long as it has the API (American Petroleum Institute) starburst logo on it, and it's the correct viscosity for your car (check your owner's manual), you can put any oil you want in there. And you're absolutely right to buy the stuff that's on sale to save money.

Tom: You are, however, probably changing your oil more often than you need to. We used to recommend 3,000-mile oil-change intervals. But engines and oils have gotten so much better that we now recommend 5,000 miles between oil and filter changes. And some people even think that's too much.

Ray: But until we decide to sell our shares of Kendall and Valvoline stock, it would be unwise of us to stretch our recommendation any further.

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.

© 1996 by Tom and Ray Magliozzi and Doug Berman Distributed by King Features Syndicate, Inc.

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