It's a thing of beauty: A brand-new car, shiny and crisp. It makes you want to spend the whole evening walking around it. Pretty soon, the neighbors wander over to congratulate you — and to render advice.

Break it in carefully, one says: "No more than 30 miles per hour until it has 1000 miles on the odo."

"No," another says. "Drive it like you stole it, if you want it to be fast."

Others recommend synthetic oil, or nitrogen in the tires, or a mouse-milk oil additive, guaranteed to double fuel economy.

The ritual of breaking in a new car is part of the body of knowledge we refer to as conventional wisdom. It's not necessarily wise, and the technology of building a modern automobile has evolved to the point where a lot of "wisdom" is obsolete. Few cars specify a break-in procedure anymore, simply cautioning you to avoid extreme acceleration or extended idling for the first thousand miles or so, and there's little in the way of extra service up front. Some don't even mandate an oil change until 6000 miles. We think your new ride deserves better. Here are a few tips.

New Car Care Checklist

Engine Cylinder Walls

Piston rings don't rely on their spring tension to seal against the cylinder bores. Instead, combustion gases work their way between the rings and the piston and force the rings outward. During the first few minutes of engine operation, it's important that the throttle be opened pretty far at lower rpms to provide this high pressure. Otherwise, the rings won't burnish the cylinder walls properly, and the engine will have high volumes of blow-by -- which means excessive oil consumption and shortened engine life. If you've ever seen the car jockeys who drive new cars off the end of the production line into the storage lot, or the transporter drivers zipping up and down the car-hauler ramps, you'll realize that this all-important step has been performed for you many times. If you're installing a new engine, simply give it a few seconds of wide-open throttle in a high gear. For the first thousand miles, avoid constant speeds and throttle settings. If you commute in normal stop-and-go traffic, you'll be fine. I advise against cruise-controlled sojourns across Nebraska.


The admonition to keep engine revs low for an extended break-in period stems from the days when bearing and crankshaft manufacturing tolerances were far less rigorous and lubricating oil wasn't nearly as good. While modern engines are assembled to much the same design clearances, the tolerances are much tighter, meaning the variability is smaller, greatly reducing the possibility of a tight spot. Redlining a fresh motor is generally a bad idea, but there's no reason you shouldn't drive normally. I would, however, avoid top-speed testing, drag racing or towing heavy trailers for the first 1000 miles.