Let's discuss my oil pres. light & oil pump.

[shaferbm]

This situation is that my oil pressure light stays on after startup and during normal driving. When the is cold, the light will flicker out occasionally (more viscous at the lower temps) and will also do this when I rev it up and the engine is fully warmed up. I checked the oil pressure sensor per the e30 Bentley manual instructions, which indicated My sensor was bad. Easy fix, so i replaced the $6 sensor with my next oil change. My oil light is still on though so I'd like some more insight as to what the deal is. My first though was the oil pump (which I already have a spare that I can swap in). I'm also wondering of it would be the SI board? I've read that when the batteries are going, they can give erratic lights.

[jlevie]

Since you could have two bad sensors, what you need to do is to temporarily replace the switch with gauge and see what the oil pressure actually is (cold, hot, and while driving). Low oil pressure could be from a clogged/collapsed filter, worn pump, bad oil pressure relief valve, or problems within the engine. It can also be caused by using the wrong oil. Where you are suggests 20w50 in all but the coldest months where a 10w40 would be more suitable.

[shaferbm]

Cool. I'll be snagging a mechanical oil pressure gauge from a relative this week. Also, I've run 20w50 all summer and will use the lighter weight once temperatures start dropping, so I'll rule that out. Hoping that there isn't a serious internal engine problem.