Dear Tom and Ray:

Is the "recommended" break-in period for a new car really important? My new Corolla's manual says that for 1,000 miles I can't drive faster than 55 mph, can't drive at steady speeds, etc. It's a bit frustrating to get a new car and be told right off the bat that I can't fully enjoy it for 1,000 miles. What bad things will happen if I ignore these recommendations? -- Michael

Tom: Well, you may develop chafing and itching around your lower extremities, Michael. And if it continues after the first 1,000 miles, you should definitely consult your doctor.

Ray: Actually, we can't say for certain what will happen to YOUR car if you don't break it in properly, but I can tell you the widely accepted theory. The piston rings don't fit the cylinders absolutely perfectly when the car comes off the assembly line. Why? Because the spaces in between the two are tens of thousanths of an inch. So the break-in period is supposed to be a time in which you drive gently and allow the rings to "seat," or mold themselves perfectly to the exact shapes of the cylinder walls.

Tom: If the rings don't "seat" well during break-in, the theory is that your car will burn oil later on, because the poorly seated rings will eventually let oil sneak by and get into the cylinders. Is it true? Yeah, probably. Although it's less true than it used to be.

Ray: Manufacturing technology has improved so much over the years that the rings (and all the other engine parts) come off the assembly line fitting pretty darned well. And overdrive transmissions further reduce the risk by allowing engines to turn slowly at highway speeds. So where, in the old days, a good break-in might have made the difference between your engine lasting 35,000 or 70,000 miles, now it might make the difference between your engine lasting 100,000 and 200,000 miles.

Tom: So it's up to you, Mikey. You can have a good time for the first 1,000 miles and take your chances. Or you can show a nose-hair's worth of restraint and have a good time for the next 199,000. Your call.

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Everybody wants a new car. But from a purely financial point of view, there is no question that buying a used car is always cheaper, even in the long run. To learn more, order Tom and Ray's pamphlet How to Buy a Used Car: Things That Detroit and Tokyo Don't Want You to Know. To order, send (check or money order) to Ruin, P.O. Box 536475, Orlando, FL 32853-6475. You can also order online.

© 1997 by Tom and Ray Magliozzi and Doug Berman Distributed by King Features Syndicate, Inc.

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