Oil Servces @ 10k miles?? Okay or Deadly

[scottieML320]

I've always been one to change oil around 5k miles, however MB says every 10k is recommended.
I asked an independent garage who specializes in MB/BMW and they said it is deadly to the vehicle to wait 10k miles b/c there is no motor oil availabe to last that long. I see his point, but I also know that routine maintenance is a big money maker for garages.

What's your opinions?

Thanks,
SCottie

[itb76]

I've used Mobil 1 exclusively for close to 10 years, changing at 9,000 - 10,000 mile intervals. An old VW Scirocco went 240,000 miles before I got rid of it, and ran fine. My old '88 Nissan Pathfinder went 215,000 miles, also ran fine, and it only held 3.5 quarts of oil! If I could make the bodies last as long as the engines I'd be in great shape.

[Tom Hock]

When Mobil 1 came out, many, many years ago, they recommended oil changes every 25,000 miles, or once a year. This was when most cars only held 4 or 5 quarts of oil. The Mercedes holds about 8 quqrts, meaning the oil only works half as hard. I used Mobil 1 in my 1985 Pontiac since new, and only changed the oil every 25,000 miles, or every year or so (whichever came first). I scraped this car at 212,000 miles because the body was shot, but the engine was still strong and used less than a quart per 1000 miles

[Gilly]

Tom:
I wouldn't really buy into saying that the oil in an 8 quart capacity works "half as hard" as one with 4 or 5 quarts of oil. I look at it more like this: You have about twice as much oil than the smaller engine, so the oil should be able to hold roughly twice as much contaminants in suspension, while still having the same concentration as contaminants as the smaller engine.
I wouldn't think twice about running 7500 to 8000 miles on a 112/113 motor oil change.

Gilly

[scottieML320]

What do you mean by a 112/113? Sorry for the newbie question

Scottie

[azinn]

Originally posted by scottieML320
What do you mean by a 112/113? Sorry for the newbie question

Scottie

112 = V6 engine, 113 = V8 engine

[Tom Hock]

Gilly,
Yes, you are correct that the oil "works just as hard" regardless of whether or not the crancase hold 4 quarts or 8 quarts. The oil lubricating the bearings is subjected to the same loads and temperature (oil temp may be lower with larger sump) regardless of the quantity of oil in the sump. It is also true that after a given number of miles, everything being equal, the oil in a sump with 8 quarts should have more usable life remaining than one with 4 quarts, for the points you mentioned.

The Society of Automobile Engineers published a 21 page techinical paper in May 1998, #981443, "Extended Oil Drain Intervals-Conservation of Resources or Reduction of Engine Life (Part II)",written by three engineers from Daimler Benz, and two from Shell Oil, covering the development of the FSS (called ASSYST in Europe). They tested many vehicles in all types of service and concluded oil change intervals up to 30,000 km (18,650 miles) and two years, under "mild driving conditions", are satisfactory. It should be noted that these tests were run with both "high performance formulations" and "borderline performance lubricants" available in European and US markets.

After reading the above paper I suspect the problems encountered with these engines, that lead to the requirement that synthetic oil be used, may have been due to a design or manufacturing change different from the hundreds of engines used in the test vehicles, and that the higher performance synthetic oil makes up for the marginal design/manufacturing in some engine component(s).

That being as it may, I now have over 60,000 miles on my 1998 ML-320, with extended oil changes (10,000 miles) and use no oil between changes (knock-on wood).

[itb76]

Yeah, but how many of our cars see "mild driving conditions"? Certainly none of mine!