Vehicle in question is a '91 300-SEL, 61,000 miles. Well maintained. I realize the engines in these cars leak oil near the distributor.
I recently experimented with a full synthetic. My oil consumption has increased noticably. I have switched back to "dino" oil, but the consumption remains higher than B4 switching to full synthetic. Would flushing this engine with something like Liqui Moly help reverse this excess consumption to some degree?

I had a similar problem with a Japanese engine; flushing the engine seemed to slow down the oil consumption after switching back to "dino" oil.

I'd appreciate any thoughts there might be on this subject. Thanks for your time.

Mike Murrell

I don't recommend switching to a synthetic then switching back to conventional oil. Are you experiencing oil leaks or consumption? You're probably looking at valve guides and seals. 103 motors were known to develop those problems.


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Rgds,
Aaron Greenberg
MB technician
Precision Motorcars, Cincinnati, Ohio
'67 250SE Cabriolet
'77 450SL
'80 300SD
'85 380SE
'89 420SEL
'93 300E 2.8
'72 Alfa Romeo 2000GTV
'74 Jensen Interceptor Mk.III
'81 DeLorean DMC12

quote:

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Originally posted by Aaron:

I don't recommend switching to a synthetic then switching back to conventional oil. Are you experiencing oil leaks or consumption? You're probably looking at valve guides and seals. 103 motors were known to develop those problems.

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Valve guide seals definitely. Valve guides? Not likely with 60k.



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Steve Brotherton
Owner 24 bay BSC
Bosch Master, ASE master L1
26 years MB technician

With the age and low mileage of this vehicle, it is very possible that it does need a valve job. When an engine sits, the top end will dry out. You start it up and it takes a while to get more lube... The dealers were doing them under warranty. Thant is less than 50k miles. You have the old style guides. They have been updated to a harder, more durable composition.

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Benzmac:
1981 280GE SWB
1987 16V
ASE CERTIFIED MASTER AUTO TECHNICIAN
SERVICE MANAGER FOR 14 BAY FACILITY
MERCEDES SPECIALIST 8 YRS
PARTNER IN MERCEDESSHOP.COM