1991 350SDL

Driving on the freeway, the oil pressure goes to zero. I coast off the next exit and park. There is oil on the dipstick. After a while there is a small puddle of oil under the engine, maybe a 1/4 cup total. No more is leaking. The car is home in the garage. I am not even going to look at it until tomorrow.

My thinking is that if there is no oil pressure, but the the sump is full, then the oil pump has failed. It is not the sending unit or the gauge, there is no oil pressure. The engine will start and run but it was just starting to get noisy due to no oil.

I have read that some vacuum pump failures can lead to this, but I an not sure if that problem applies to this engine. I will be checking the FSM for the oil pump R&R.

Has anyone else experienced and resolved this issue?

Thanks,
Greg

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Greg
2012 S350 BlueTEC 4Matic
2007 ML 320 CDI
2007 Leisure Travel Serenity
2006 Sprinter 432k
2005 E320 CDI
1998 SLK230 (teal)
1998 SLK230 (silver)
1996 E300D 99k, 30k on WVO
Previous:
1983 240D, on WVO
1982 300D, on WVO
1983 300CD, on WVO
1986 300SDL 237k, 25k on WVO (Deerslayer)
1991 350SDL 249k, 56k on WVO - Retired to a car spa in Phoenix
1983 380 SEC w/603 diesel, 8k on WVO
1996 E300D 351k, 177k on WVO