How long does "break-in oil" need to stay in the car?

Dear Car Talk

Dear Car Talk | Jun 01, 1991

Dear Tom and Ray:

My family owns two new cars, and we've heard mixed messages about that first oil change. A co-worker told my mother that she should change the oil in her truck the moment it reaches 1,000 miles. The reason being when an engine is "broken-in," there can be metal flakes and chips that come off and float around in the oil. Another friend said that we should never change the oil before the manufacturer recommends. According to this friend, that's because the factory puts in a special "break-in oil," and removing it too soon will cause premature wear. To make things even more confusing, another co-worker told me that she changes the oil the minute she gets a new car home. She says that they cut costs at the factory by using a cheap, low quality motor oil in all new cars. Who's right?

TOM: These are great questions, Steve. We've discovered that motor oil is one of those areas of life shrouded in myth and mystery....kind of like curing hiccups or restoring hair.

RAY: Anyway, we can start by eliminating the cost-cutting theory. The manufacturers don't cut costs by using poor quality motor oil. They cut costs by using things like miniature spare tires and two-and-a-half mph bumpers. It's simply not in their best interest to do anything that would harm the engine, since the cost to their reputations would be far greater than the few cents they'd save on oil. Besides, they'd probably be the ones who got stuck fixing it under warranty anyway.

TOM: The "special break in oil" theory also sounds good, but it, too, is a myth. We've heard about this mysterious oil for years. But we've talked to some of the top oilologists is the country, and we can't find any proof that there ever was such a thing as special "break-in oil."

RAY: So the answer to your question is that you should change the oil on a new car at somewhere between 500 and 1,500 miles. That's the time when most manufacturers recommend that the car first be serviced. And even if your manufacturer doesn't recommend an oil change then, it's a good idea to do it anyway. It certainly won't hurt the car.

TOM: Tiny metal particles can come off the inside of the engine during break-in. Although these particles may be so small that you can't even see them, they can be abrasive and destructive when they're circulated around the engine.

RAY: The oil filter will catch any??thing larger than a few microns, so don't worry about Coke cans or sandwiches that fell into the crankcase along the assembly line. But that early oil can get saturated with contaminants fairly quickly, so it's a good idea to get it out and get some fresh, clean oil in. Enjoy your new cars, Steve.

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