My 1999 W140 oil pressure seems to continually get less as the days go on. It sets at 1 when idleing, 2 at cruise. I changed the oil and replaced the plugs just last week. The oil level has not changed and I see no oil leaks except a minor sepage around the gasket. I noticed that two of the old plugs- one from each side had oil on them. I am right at 190K..what should I be expecting to repair?

Low oil pressure is usually indicative of worn bearings on the crank. BUT it could also be a weak oil pressure sender unit.

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