I have a '90 300se with about 200k miles on it. I change the oil every 5k miles but lately I have been noticing that the level of the engine oil has been decreasing at a rate of about 500ml every 5 weeks or so. Is this normal or should I do something about it?

How many miles do you put on in 5 weeks?

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'83 300D

I put in roughly around 1500 miles in 5 weeks.

I was always told that using a quart of oil, in 1000mi or less, was considered "burning oil". So, it looks like you are inching your way towards that mark.
Of course, before thinking engine rebuild, you can externally check out the engine from top to bottom, just to make sure your not loosing your oil through leakage. Sometimes oil can get dragged long the chassis a ways before being flung to the ground.

btw I think that many owners (not neccessarily Benz owners) would be very happy to have an engine with 200k and using 1qt. of oil every 1500mi.


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'83 300D

I think this series inline six had some problems with the valve guide seals or valve stem seals (?). Losing 500 ml every 1500 miles is about a quart every 3000 miles. Not bad, yet. My '77 300D was at a quart every 600 miles, but it could have been from a lot of oil leaks. If the car sat for a week or so without being run, the oil level still dropped.

Check your oil before and after long trips. That should indicate if you're losing oil though blowby. On my '77 300D I saw puffs of smoke if I removed the oil refill cap and then started the engine. Mine produced a cloud of smoke a couple feet high. Does this indicate blow-by?

Anyway, I later sold the car. It's still running, as far as I know, though the owner probably carries a jug of oil in the trunk

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Robert W. Roe
1984 300SD 165,971 miles


[This message has been edited by Robert W. Roe (edited 10-13-1999).]