Originally Posted by Selden

All the above advice has been spot on. The idea in break-in is to put the engine through lots of heating/cooling cycles, and to vary the load on the engine in order to seat the rings, while avoiding extremes of low or high RPMs. A thousand mile trip along the Trans-Canada highway with cruise control engaged would not be a good technique.

The only thing that generates any controversy is when to do the first oil change. Most of us who have been working with cars for a long time are accustomed to a quick initial oil change, followed by oil changes every 3000-5000 miles. This worked for my father's Buick in the 50's, but is not necessary with new engines, and in fact, a Honda tech on this forum specifically recommends against changing the oil before the meter gets to 15% oil life, which will probably be between 6,000 and 12,000 miles, depending on your driving conditions. This is very difficult advice to accept, but do it if you want your engine to break in properly. If you haven't hit 15% / 12,000 miles after 12 months, ask your dealer for a recommendation.

Originally Posted by blue line

I first picked up my new Fit in Boston. I had all good attentions of babying it for at least the first 500 mi. Untill I left the dealership and found myself out in Boston's mainstream traffic, were they will kill you if don't imediately slam the accelerator to the floor at every green light, followed by extreme braking at your very next red light, which is about 100yds away. After 7 miles of this, my new car was well broken-in.- Attending school there in the winter

Originally Posted by Texas Coyote

I have done it to every engine I have rebuilt or came new in a car or motor cycle for over 30 years with no negative effects.... It is the best way to seat the rings. At 30000 miles with 11000 supercharged I have no blow by problems, oil consumption between oil changes or any other problems..... How do you think that racing engines are broken in?...... I take it easy for awhile driving at different RPM lightly accelerating and gradually changing load and speed and decelerating on hills to put some wear and pressure on the back of the connecting rod bearings and main bearings so there will be no uneven surfaces that could cause hot spots and galling. I then gradually increase the throttle opening until it will go no further and after 30 or 40 seconds start slowly lifting the throttle until I am driving easily with a light load on the engine to allow the temperature to slowly return to a lower operating temperature before shutting it down.