I had a ex-MB mechanic, now independent, evaluate the problem. He found the "O" rings on the oil filter stem rock hard and said they should be changed with each filter change. He said my hard "O" rings could be the root of my problem. He replaced the "O" rings but we did not get an improvement, he says the oil pump could have failed due to starvation caused by the "O" rings. He confirmed that my oil pressure is a problem and is hoping a new oil pump will solve the problem, but that it could be worse.

He also suggested that I talk to the MB dealer that should have changed the "O" rings and didn't.

Has anyone here experienced oil pressure failure due to these "O" rings?

I would appreciate any advice on how I should approach the dealer.

Thank you.