I just changed the oil (and filter) in my e21. The car started up fine, but the oil pressure light stayed on. I took off the pressure gauge to see if oil was coming up and through, which I did not see any presence of. I changed back the filter to see if it was the new filter, but that didn't fix it. I am wondering if I might need to prime the fuel pump or if it could be that the screen for the oil inlet could be clogged. It was running fine before the oil change with no light on, so I don't think it could be a pump or chain failure. I am planning on just pulling the engine out and taking out the pan, but if I can fix it without that, I would like to. Any help or ideas appreciated!
I know much time has past since your post. I have had customers experiencing the same issue. That said, if it helps anyone I have seen many time customers installing too heavy of a viscosity oil in the engine. When cold the oil pump can not draw the oil up through the sump. This may or may not have been your cause however, since no one replied, I wanted to share these experiences with others if it can help.
