John - you may have just saved me a lot of work. My 560sel is in storage all winter and it is only summer driven. When I took it out for a 30 mile drive for the first time this year the oil guage stayed pegged as normal. However on the return home trip it slowly started falling to the point it hit hit 1.5 bar when I got home. Turned the car off and on and it went up to 2.5 bar then jumped downward and settled in at 1-1.5 bar. Did this many times with turning ignition off then on again with same results. Next morning started it up and all was well - as soon as the engine was up to temp - the same needle drop happened again. Ordered a new oil sending unit and installed. same thing. Got busy on my other cars and put off fixing it until this week end. Did yours do the same thing? Could the answer be as simple as the brush pak in the alternator? I was getting ready to pull the instrument cluster and check all connections for a bad connection then go over all the body grounds.Then as a last resort was going to hook up a pressure guage to make sure the 60 lbs oil pressure was really there. The action of the guage hints more at electrical than mechanical problem. Please advise ASAP so I can pick up a brush pak if required
Many thanks
Morris