Piston Slap: How Not to Break-In a New Engine
Kathy writes:
Hi, Sajeev. A coworker recently bought a new commuter car. Not some fancy $25K+ sports car (under $20K “sporty” commuter car). He talked about breaking in the new engine hard for the first 120 miles: putting the auto into gears 1 and 2 and redlining it. Driving 0 to 120 to 0 to 120 mph.
Supposedly it makes the engine better. Where does the TTAC community stand on this: easy or hard break in for a new car?
Sajeev answers:
Holy crap! Putting it mildly, your coworker sounds a bit extreme. And extremes are never good on a new engine. Loading the engine at various RPMs ensures piston rings and valvetrain components seal properly. You never want to set the cruise control and take a long drive in a new car. Always vary your speed, or at least go between different gears at the same speed.
That said, I am not a fan of running near redline for the first 200-500 miles. Breaking in a motor means gently coaxing moving parts into their new home, not forcing them in with a jackhammer. I also do not recommend switching to (i.e,. not used from the factory) synthetic oil at this time, let the motor break in first.
This is a very controversial car-care subject, to say the least. So, Best and Brightest, give us your thoughts on the matter.
[Send your car questions to mehta@ttac.com]
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Sounds like a winner to me. Hence why I tried to moderate the original answer by giving a middle of the road description of engine break in.
Sajeev: "[I gave] a middle of the road description of engine break in." Not really. You still took the side that moderate use of new engines (i.e., break in) is good. The true moderate position may be that hard use of any engine is, well, hard on the engine. And there is no evidence that break ins accomplish anything. :-)
But I tried not to, hence why I said "tried" in my last post. Anyway, we all have to have faith in something, so as long as both sides are happy in their (blind and baseless?) faith, I'm happy to move on to the next Piston Slap conundrum.
I had a 2000 Civic SiR and now a 2003 Mazdaspeed Protege and did not follow any break in period. I did hard accelerations up to redline from day one. Civic had nearly 100000 kms and my Mazda has 175000 kms. Neither engine burned oil. I never do a WOT on a cold engine, and let the turbo cool down after a hard run. Never had any engine issues. I think common sense daily driving matters more than break in period.