oil pressure light

[silverjay]

My oil pressure light is driving me insane. About 6 months ago I purchased a 1998 328i. A few days after I bought it I changed the oil and as soon as I pulled out of the oil change place, my oil pressure light started to come on when I would idle. If my foot is on the gas pedal, the light goes out. I took it to the dealer and had the oil pressure switch changed, but that didn't help. The mechanic said my oil pressure is ok. Then he said that it is possible that the oil I put in, 5W30, is too light a grade. He recommended that I put in 10W30 and he said that would probably fix my problem. Does this sound right to anyone? Is is possible that the previous owner used thicker oil and my changing it caused the light to flicker on?

[njtech]

did the oil change place fill it back up with 5w30 or 0w40 synthetic. How about the filter? is it a oem quality or an inexpensive brand? I would start here. If you need more info email me.

[silverjay]

I had been using 5w30 but today I changed it and put in 10w30 part synthetic and I used a genuine BMW filter. It made no difference. I did however realize that the oil light only comes on when I dip down to 1200 RPM or lower. Like when coasting or coming to a stop. My friend just told me that it sounds like the sending unit. He said it somehow has a relation to RPMs. Does this sound right? It sucks I just changed the oil pressure switch for no reason.

[nycbmw325is]

Originally posted by silverjay@Sep 17 2004, 07:41 PM
I had been using 5w30 but today I changed it and put in 10w30 part synthetic and I used a genuine BMW filter. It made no difference. I did however realize that the oil light only comes on when I dip down to 1200 RPM or lower. Like when coasting or coming to a stop. My friend just told me that it sounds like the sending unit. He said it somehow has a relation to RPMs. Does this sound right? It sucks I just changed the oil pressure switch for no reason.

oil pressure is lowest at low RPM (like idle) it rises with RPMs until it levels off somewhere probably in the 3-4 K rpm range. Since you changed your sending unit, and you are still seeing this light come on.. you need to explore the possabilty that you have perhaps a clogged oil pick up screen in your oil pan, or your oil pump is failing. If in fact you really are at 1200 rpms with insufficient oil pressure it is the same as executing your engine . deal with this right away, before you sieze a bearing and wreck your motor.

[theogill]

BMW dealer uses 5W 30 synthetic in my car. Weight of oil should not be the issue with your oil pressure. BMWnyc325 guy sounds like he knows what's up. Follow his advice. Good luck!