'94 E320t Oil Pressure Too High

[RobertFini]

Ever since I bought this car, the oil pressure gauge has been pinned at the maximum whenever the engine is running, even at idle when fully warmed. I thought it was a faulty gauge, but today when I was changing the oil and filter, the filter housing was still full of oil even though the engine had not been running for at least an hour.

I sucked the oil out of the housing with a tube, and a visual inspection revealed nothing out of the ordinary except for some very dirty oil after only 6k miles between changes. I suspect that there is some blockage that is causing the pressure to be too high and also keeping the oil from draining back into the crankcase, and possibly preventing the oil from properly circulating through the filter (causing the filthy appearance).

Short of a teardown, is there anything that I can do to resolve this problem?