Well I actually came on this information by accident while reading up about my favorite car, the C6 Vette. I'll copy and paste the interesting stuff:
New Car Break-in
When a car is new all the parts in the engine and drive train (primarily the transmission and rear end) fit very tightly together. As the car is driven these parts start to wear against each other. The goal of new car break-in is to minimize wear that can damage the parts. Not only can this prolong the life of your car but it can improve the performance of it as well (like better power and gas mileage).
The Owners Manual provided by GM with my Corvette said only to drive the car under 55 MPH for the first 500 miles and to vary the speed. This write-up expands upon that including how to drive the car when the engine is cold, how to drive it in general and what kinds of maintenance to perform.
Cold Starts
The most detrimental time for your new car is when the engine is cold. You want to minimize the time it takes your engine to get to normal operating temperature and be easy on the engine until it is up to temperature. The following is recommended:
* Avoid cold starts - plan your driving such that you can start your car and go for a moderately long drive. Try to avoid short trips. * Drive the car immediately - idling the engine causes uneven engine wear. Get yourself ready to leave (buckle up your seat belt, adjust the seat, etc.) before turning on the engine. When you turn on the engine put it in gear and leave immediately. * Accelerate moderately - never use more than 1/4 throttle while the engine is cold. * Excessive throttle can cause engine glazing and uneven wear. * Shift gears at under 2500 RPM - dont over-rev the engine.
Driving
During the first 500-1000 miles your engine and drive train parts are establishing a fit that they will have the rest of their lives. Try to follow the following procedure for the first 1000 miles or so. If your car uses synthetic oil you may want to extend this even longer because synthetic oil slows engine wear.
* Keep your speed under 55 MPH for the first 500 miles. * Dont accelerate overly hard. * Avoid full throttle starts from a dead stop at all costs - there will be time for that later. * Continuously vary your speed - its tough on you and the people following you but try to change speeds constantly. The worst thing you can do is use your cruise control. * Drive on slow-speed trips as well as moderate-speed trips - so you can use as many gears as possible. After 500 miles, add high-speed trips, too. * Do not exceed about 3500 RPM. Make your shifts smooth and deliberate - not only are you breaking-in your engine, you are breaking-in your transmission and rear end. * Never lug your engine - if you have a manual transmission, try to keep the transmission in a moderate RPM range. * Try to drive during cool temperatures - overheating is the enemy of new engines which tend to run hotter until they are broken-in. * Try not to use your air conditioner - this helps reduce the temperature of your engine by eliminating the load of the compressor. * After a long highway run, let your motor idle for a few minutes - this is an exception to the no-idling rule which lets the engine cool down a little
Unfortunately I did not follow any of that advice for my Accord. None of that stuff is mentioned in the Accord owners manual either. I've been using the A/C every day since I bought the car, I have not been able to drive the car in cool temperatures (it's hot in Texas during the summer!), I have definitely exceeded 3500 RPM's, and I have definitely exceeded 55 MPH (try 80 and 90 lol!), and I definitely haven't been worrying about varying my speeds all the time, especially not on the freeway which could be dangerous. I don't lug the engine I don't think, and I haven't done a full throttle start, but I'm a little concerned about all of this stuff. The Accord manual is very vague about engine break-in so I really didn't think much about it. Oh well, I hope I didn't do any damage. With 500 miles on the odometer it's too late now, according to the manual break-in should be done in another 100 miles, so following all of those recommendations probably wouldn't matter anymore.
How about you guys, did you follow any of this stuff?
None of that stuff is mentioned in the Accord owners manual either. I've been using the A/C every day since I bought the car, I have not been able to drive the car in cool temperatures (it's hot in Texas during the summer!), I have definitely exceeded 3500 RPM's, and I have definitely exceeded 55 MPH (try 80 and 90 lol!), and I definitely haven't been worrying about varying my speeds all the time, especially not on the freeway which could be dangerous. I don't lug the engine I don't think, and I haven't done a full throttle start, but I'm a little concerned about all of this stuff. The Accord manual is very vague about engine break-in so I really didn't think much about it. Oh well, I hope I didn't do any damage. With 500 miles on the odometer it's too late now, according to the manual break-in should be done in another 100 miles, so following all of those recommendations probably wouldn't matter anymore.