Hi guys and gals.

I have an S202.082, which is a w202 wagon with M111.944 192ps 2 liter kompressor (supercharged) engine. The car has 480,000 km.

I got it cheap in september 2015 with about 477k km. It had been used mainly on highway journeys.

Engine was OK, MAF was shot and oily. I had all fluids and filters changed and other service like brake pads etc. I also converted it to run on LPG.

I also disconnected the breather hose and let it vent in the air. I also disconnected and blocked the small vacuum tube connecting the s/c plenuum with the oil separator (based on what this guy did http://www.benzworld.org/forums/r170...y-factory.html). Strange enough, I could see some times vapor coming out of the oil separator but no oil whatsoever. There is no visible blow by from the oil dip stick or when opening oil fill cap with engine running (only some oil splattering around).

Currently only MAF is the main issue which has led the ECU to deactivate the s/c.

During city and short (20 km) highway driving the car doesn't use any oil at all. I did a longish 400 km round trip (2/3 highway) and had to add 2 liters of oil (1 liter mid way and 1 liter at the end) as the oil light kept going on and off. Now the stick is showing 1mm below max and hasn't moved from there in the last 150km of city driving.

I talked to my mechanic and he told me most probably it is the valve seals. I read a bit about the valve seals and people are saying that the most obvious thing when valve seals go bad is a plume of smoke on start up after a long rest. I haven't seen any smoke on start up or while running.

Any idea what to look for?

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1992 Mercedes 190D 2.5 turbo 5sp manual. EGT+boost gauges. Boost controller set to ~14.5 psi. 1 1/4 turns on full load adjustment. LPG injection. Next in the list is water injection.