I'd think that there would be a warning light and/or alarm that would indicate no oil pressure if it would drop to null (or a lack of engine oi in the sump too), but can't verify this because I don't have a 95'. My older Bimmer (electronics from here to hell and back) has both a gauge and pressure warning light so I don't see why the MB wouldn't too.

I'd have the gauge replaced/tested before you pull the pump. If it's an oil line that runs to the gauge in the dash, could it be clogged? Does the oil pressure run at its precise normal pressure while driving or lower too?

Sincerly,

ATLD