yvette

Can you tell me what to do or not to do while breaking in my new C Coupe?? It's been 10 years since I have had a new car! Thanks...I have learned so much from you all! Yvette Black/Charcol 6sp cd,sills,c5,c7

mbtech208

Break-in periods are all but gone. All you need to do is drive your car normally. Don't beat the hell out of it, but don't baby it either. Drive it like your average Joe. Shift at normal RPM's (3-4,000 rpm), but if you need to floor it for passing or merging, by all means do it. I have yet to see a modern engine fail prematurely because it wasn't "broken in properly". I did replace an engine on a 2001 ML320 that only had 30 miles on it, but that was a freak manufacturing flaw.

Mike T.

...which says that the best thing is to keep engine speeds moderate (<4000 rpm) for 1000 miles, then progressively reach higher into the rev range over the next 1000 miles or so. I'd refrain from maximum revs until after 2000 miles.

Also, vary engine speeds during the first 1000 miles. DO NOT cruise at steady speed on the highway. If you must drive on the freeway, drive like a bad taxi driver - on and off the gas, even on level road.

mbtech208

Good words of advice, Mike. Although in the real world, if I bought a new car and was taking it on a long trip, I'd set the cruise control and fly. On and off the gas, varying speeds would get old after about 10 miles.

Spyke

This is something I'm wondering about as it looks like I'll be getting my car at about the same time I'm taking a roadtrip... I had wanted to take the C230 but if it arrives only a few days before we leave???

I have also heard not to do the highway drone on a new car, but on the other hand I took my new Nissan SE-R on a 650 mile highway trip with only a few hundred miles on it, and it never gave me a problem in the roughly 80,000 miles I owned it.

DtS

I took my C200K on a 2500km/24h one way trip when it had only 2000 km on the odo. I belive this havn't hurt my engine at all.

mdp c230k

There are a bunch of old threads on this topic that might help you do the right thing. Remember, you are establishing wear patterns on you engine that will remain for life. I have had great luck by being gentle the first 1000miles then taking the engine through its entire rev range without 'flooring' or 'lugging' the engine. If you gently rev the engine without a lot of load on it there will be no harm. If you rev at a constant speed you will create ridges on you cylinder walls (after a long, long time) that can cause ring seating problems when you rev at higher rpm. There is a very small amout of stretch of the connecting rods as rpm increases and the rings will hit these ridges and jump letting gases blow by and wearing prematurely. If you break the engine in by running through its full normal operating range you will not set these ridges up in the first place and it will be smoother and last longer. Happy motoring

MB-BOB

I picked up my car in St. Louis last May 3, and by 7pm on May 4, had put 840 miles on it (including a 670 mi., 10-hour drive from St. Louis to Dallas--72 mph avg speed, 98.5% on the Interstate--cruise control all the way). I had no time for varying speeds.

The car hasn't broken down, yet. In fact it runs great at 9,000 mi. Gas mileage is improving with each passing day.