I believe that on the N52 engine the oil pump is a "constant pressure" pump because of the dbl vanos. Therefore engine RPM should have no effect on the oil pressure.

 

Probably so but my engine is M54B30.

 

I had this problem after about 40,000 km at like what you have described, at low speed, while the engine is hot! Very often, in my case, it happened after I have reverse-parked into a multi-storey parking lot.

As recommended in the puma, SE changed oil pressure sensor and up the idle by about 150.

I took the car and was back to the workshop the very next day as I felt the car was idling too high (even on D and really feels like its rattling all over, especially on the steering wheel).

He confirmed that having the rev up by 150 will cause 2 problems, one is fuel consumption and the other is the tranny. Naturally, he forgot the third -> my wrath!!

We have since put back the idle speed to what was previous and the message has not come back (approx. 15,000 km done since).

Hope this helps. Cheers

 

Thanks. If I understand correctly, they did nothing, just restored normal idle rpm, and the problem went away by itself?

 

I had a jaguar v12 once that did something similar - the oil light would come on when the engine was hot and approaching junctions, or in traffic. when cold it would easily exceed 60 psi. I think for that engine it was pretty normal. However, low oil pressure can be the result of a failing pump, or general engine wear. As clearances increase due to worn bearings etc, the oil flow increases and the pressure drops. However your mileage seems pretty low - so unless someone has very badly mistreated it (run out of oil, didnt change it, crap oil) wear would be a less likely option

cheers

steve

 

I just left the car at my dealer this morning. Lucky for me, there was an engineer from BMW AG there for some training, so I discussed with him and he told me he will also try to see what's wrong. So I will keep you posted. From my discussions with him, he said, it can be the oil pump...

 

My car is back from the dealer. They said they just increased my idle engine speed but not in general. Just when there are some consumers. They said they have the option to choose from 4 big consumers and increase the idle speed only with those (A/C, fan, etc). So, the idle speed looks just a bit higher than it was, nothing I can complain about so far. From the needle I'd say it's 700-750 rpm. I'll check more carefully.

 

Problem, never occured again, after the increase in idle speed.

 

Good to know.