M117 Oil Burning Issue - Page 2 - Mercedes-Benz Forum

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post #11 of 13 (permalink) Old 11-04-2008, 12:37 PM
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Date registered: Jan 2007
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OK, here's a theory.

The oil pressure bypass is not working correctly. When you drive the car with a cold engine, you have execessive pressure forcing oil somehow into the combustion chamber. It doesn't do it when you let it idle because the oil pressure doesn't get high enough.

Chuck Taylor
Falls Church VA
1998 SL500
1959 220S
1970 280SL
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post #12 of 13 (permalink) Old 11-25-2008, 09:20 AM Thread Starter
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Date registered: Oct 2008
Vehicle: 1972 280SEL 4.5
Location: Colorado Springs, Colorado
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(Thread Starter)
A discovery!

In the process of changing the water pump, I found a short, obviously broken flexible line connected to a banjo fitting on the front of the block by the oil thermostat. Anyone have an idea where it is supposed to be connected to?
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post #13 of 13 (permalink) Old 11-27-2008, 03:17 AM
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That sounds like an oil feed for a air suspension compressor. You sure that' the original engine? or does your car have air springs ,or had air springs..?. i have replaced a few of those hoses over the years on 300SEL 3.5's ( reasonably common here) . They sweat oil for years before anyone notices.
The engine smoking sounds to me like a worn rings and/or a broken piston . The engine has drilled conrods and there is a LOT of oil spraying around under the pistons. a crack will close when hot and running as will ring gaps . A cold leak down test is in order. A compression test won't tell you what is wrong.
Another thing i have found over the years is when these engines were assembled in the factory ,some idiot has placed all the ring gaps in line. Thats OK for the 100-200,000 miles but eventually the blowby defeats everything.

Yet another Hot rodder..26 Chev roadster with 3,5 M116 power.
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