Break-in Period
 

Did anyone read in the owner’s manual that during the 1000 mile break-in period the trans should be in the “C” mode? If so are you following this advice?

I would definitely suggest that you follow the advice so that you can keep the car longer without having any problems. I would definitely do that myself when mine arrives later.

Good looking out, I can’t remember the last time a read an owner’s manual. Plus the C300/350’s manual is the most boring one I’ve ever seen. As a side note my dealer told us to not use C as it consumes more fuel, and is harder on the trans as it has to start in 2nd first or something to that tune? I’m not sure but I’ve been leaving it in S having said. In contrast I use the 500-mile rule. No hard starts, let engine fully warm, avoid hard breaking and avoid full throttle for the first 500 miles. At this mileage I introduce random partial to more spirited passing and accelerating on the highway, mixed cruising speeds 68 for a while, then 70-80 for a few moments. I do this until about 1000 when I always change out the factory break-in oil and then start to give the car some more pedal.

You should ask a service guy at your dealership, "C" does not effective gas mileage. In my '05 C230 I did not see a difference when using "S" of "C". I followed the recommendation but if this is really important why not put it on page 1 instead of burying deep in the manual.

There is no break-in oil in these cars.

There is no 500 mile rule as far as the engine is concerned. The engine is fully machined, planar honed, and polished to be ready to go from "green run."

There is no benifit to "warming" the engine. The motor electronics will take care of that. Simply start and drive off at a moderate pace. Within seconds you can drive in a manner many will call spirited.

The oil in the crankcase is the same as the Mobil 1 0W-40 (conforming to Mercedes Benz Sheet 229.5) that you buy, except the factory gets it in railroad tank cars, and you buy it in a quart bottle.

Do drive moderately for the first 500 to 1000 miles with the tranny in the C (comfort) position. The transmission fluid and friction material are designed to work together, and they need some time to become aquainted. Running a new transmission with new friction plates and new fluid requires easy going for a bit. That is why the C mode is suggested. This mode will save fuel, and enables the hill holder function. The S mode will start in 1st gear, and will allow more adventuresome motoring.

As for the location of the break-in instructions in the manual, I notice that the golden rule and the ten commandments are not on the first page of the Bible either. You need to read the whole thing.:D

As always, informative, witty and worthwhile. I wish all posters (myself included) could be as eloquent and useful as Moviela is.

Great biblical analogy, by the way.

Oil
 

>>The oil in the crankcase is the same as the Mobil 1 0W-40 (conforming to Mercedes Benz Sheet 229.5) that you buy, except the factory gets it in railroad tank cars, and you buy it in a quart bottle.>>

5W40 EP, actually.

I know these new cars are broken-in from the Factory and my oil changing at 1K miles seems redundant, but I've done this with every car I've been able to purchase "new" not saying it's wrong or right, but it's an old "Grand Father" tale that I stick too religiously. I purchase new trucks every two years roughly and personally break them in before handing them to employees, so going by my rule of thumb is basically insurance I can use no matter what vehicle I own.

-Ryan

This is directed at anyone, I am going to get my car from Chicago in October, and will have to drive south about 300 or so miles and was wondering if going 70-80 would be a bad idea if I gently got to those speeds, on a brand new engine.

Additionally, this is the first car I've ever bought (I'm 21) and was wondering how often the oil changes are (since we're on the topic), coming from a car with 3000-5000 mile oil change breaks.

Thanks

break it in hard!!!!!!!!!!! - no kidding, i believe they dyno each and every car before leaving the factory and that isn't exactly "babying" the car.

oil changes are at every 13,500 miles or 1yr, whichever comes first

Just stomp on the gas and let the tires spin. Its the only way to break the engine in. then again that is just my advice, since thats what I do with my cars.

Trip
 

If you are going to travel on the highway for a long distance when you pick up your car, vary the engine and road speed. It will be fine if you do.

TEAShea
from Nebraska

I've always been told that "high heat and low manifold pressure" is how you most effectively break in an enigine..."seat the rings" and get everything working together without stressing any of the moving parts early on. This means high sustained speeds for long periods of time (varied slightly) are ideal but hard starts are something to avoid.

Anyone else hear this or did I dream it?!?

- Peter

a lot of this simply dosen't apply to modern engines.

Lucky you all. I have to break my wallet first before break-in a new car.

Always
 

Every auto forum has this same discussion - usually in multiple threads. There are a variety of opinions on this. I take a middle road myself. I generally stick to less than 4500 rmp for the first thousand miles, but with briefs runs un to 6000 or so.

The most important thing (in my opinion) is to vary the engine and road speed for the first 1000 miles. No cruising at the same speed for too long.

TEASha
from Nebraska

Does the road speed matter as much as the engine speed?

I'd always adhered to break in procedures, as listed in manual plus those old "dad's" tale items passed down. As an experiment, I had a BMW 3 series that I knew I wasn't going to keep for very long (convertible, bought it because I'd never had one before) and I beat the hell out of that car from day one.

By about 12k that car felt like it performed better than any other car I've ever owned. Only kept it till 26k so who knows about long term. And I know it isn't a scientific experiment. But most of the other german cars I've babied have eaten oil, this one never used a drop.

And I still can't bring myself to stomp a new car like I did that one, but I certainly don't concern myself with how I'm driving either.

Speed
 

Road speed does not matter as much as the engine speed but it is not insignficant. There is more than the engine to break in. The wheel bearings, transmission, etc. all benefit from some break-in. Some of these are dependent on road speed as opposed to engine speed.

TEAShea
from Nebraska

I think the way you do, to a point. The C is my wifes so in all fairness it is probably getting broken in the “right” way. But I’ve got a fleet of trucks I buy every two years for my business. The latest one I’m driving a 2007 Toyota Tacoma “Pre-Runner” x-cab with the 2.7L Engine. At any rate I bought this truck for a new employee back in January the truck had 4 miles on it when I got it, long and short the employee didn’t work out and I’ve been driving the said truck as a daily work truck since January, it has had 800+ lbs +/- in the bed since day one, has to pull multiple hills etc… My foot is in it 90% of the time and has been since new as to keep a tight schedule. Long and short this truck has been beat to death in a very short time, it has 33K miles YTD and doesn’t rattle, burn oil, gets a consistent 21 mpg loaded and has never been back to the dealer for anything. I also have accidentally gone some 8-9K miles before changing the oil in it. I think break-in procedures are overrated, but I wouldn’t over look these procedures if I were driving a performance version like an AMG. The drive trains, gears and suspension is under so much more stress than per se a C/300-350.

-Ryan

a friend of mine bought an used SLK 350 with 1500 miles on it. That car had very serious oil consumption problem. after he brought it back to the dealer and left it there for 3 days, the problem has gone. The answer from dealer for the oil consumption is the engine wasn't broken-in well which casue the posion rings didnt seal tight enough. the trip meter on his car after the 3 days "fix" was read 14 miles/gal. The car must be bit the hall of it in that 3 days, but the problem has been fix forever. Now, you tell me what's the right way to break in an engine.