If your conclusion led to drive it like a grandma(ie follow manufacturers suggestions) or drive it like you stole it (sorry to say, negligent advice) then you either are looking in the wrong places or misunderstanding the advice. Breaking in a car is a mix between and science and an art. Driving it like you stole in the first few hundred miles will most like damage your rear end or tranny before the motor. I agree with keeping the rpms below the manufacturer suggestions but only during breaking in the engine and drive train. The art comes to varying rpms, hard acceleration, engine breaking all while warm with cool down periods under manufacturer rpm break in suggestions. Once you have properly broken in the motor and drive train you can drive it like you stole it or like a grandma.
I will add another piece of critical information that I left out...for cars with lower tolerances and lower compression break in period is less important. As you go higher in tolerances and higher in compression proper break in is more important... I also want to add and agree break-in most affects the amount of oil consumption later on... But it can also ensure consistent performance as the engine ages...it will most likely not affect the life of the car though. You want the best seating of valves and rings to maintain the proper level of tolerances resulting in highest consistency of compression.... So if performance is not your priority or oil consumption then drive it like he manufacturer states...
Don't drive it like you stole it either!. Break in the car properly... Do the cycle 3 times or more with one or more hours to cool (full engine cool down) up to 500 miles and your car is broken in... I usually spend 2 to 3 days breaking in a car or mc... Change the oil then drive it like I stole it from there....
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Originally Posted by Tony M
I read all the info I could find on the internet re "break-in". It took many hours over several nights.
In the end I was no wiser. Both sides of the argument could sound equally plausible. Eventually i reasoned that a lot of the "drive it like you stole it" protagonists were arguing from anecdotal evidence and limited detailed knowledge of the specific metallurgy, piston ring design and oil performance characteristics of this particular engine.
So, I decided that the best thing to do in the face of considerable doubt and uncertainty was to follow the manufacturer's recommendations, perhaps erring slightly on the side of pushing it a little harder when fully warmed up.
The thing is that I did precisely that with my last car (4 litre turbo Ford) even though I intended to only keep it for 2 years. 11 years later, I gave it to my son as it was just too good to part with. The engine was always faultless and never used oil despite being driven enthusiastically a lot of the time.
I feel fairly sure I'm doing no major harm by broad adherence to BMW's recommendations, but I'm not so confident about following internet threads urging the "drive it like you stole it" mantra.
Just my 2c - YMMV.  |