Hi guys,
I seem to be have a problem with my 525d(2004). The low oil pressure light came on a couple of weeks ago and I have been trying to get to the bottom of it.

Took it to stealership and they did diagnostics and reported no codes. They told me it had more oil so they drained it to normal levels.

Anyway got it back and still the warning on idrive and red oil lamp on speedometer.

Got dealers to check oil pressure using gauge as from what i have read that was important.
Dealer says pressure is fine.
So my guess was that the oil pressure switch was faulty got it replaced and the warning is still there.
Any ideas or anyone been there?

I know nothing about your engine and whether it uses the same oil pressure switch as the N62.
The switch on the N62 is known to leak and give a false error (happened to me). How did the old one look like? Was it leaking? If it was, I would look closer to the wiring that attaches right to the switch, there might be oil still left in the clip/plug.

The engine is the 2.5l not 3l diesel its prior to lci.
The switch is the same as seen on these forums. It did have some oil on it but not a great deal.
I havent looked at the wiring to see if oil there. .would that short them though.
I'm thinking maybe its the wiring or i have a leak somewhere...but the oil level is fine on dipstick.
Maybe its the pump or oil filter housing or valve gaskets...
Was thinkin of taking to electric specialist.

I've had more that one car in my life with a defective oil pressure sender. On your car, the sender is like $10. If it were me, I'd Just replace it and see what happens.

defective oil pressure sender. Is that the same as oil pressure switch...as that's been replaced for £30.
Not sure what else is required.

If it was my car, I'd keep debugging it. On previous cars when I suspected oil pressure problems, I hooked up a manual oil pressure gauge. It will consist of a brass fitting that fits in place of the oil pressure sending unit. Out of that fitting is a small plastic tube that hooks up to an oil pressure gauge. In the old days, you could get one from the local auto parts store. Something cheap like this:
http://www.autozone.com/autozone/acc...er=889864_0_0_

In the BMW, it is possible the car won't like the BMW sending unit being disconnected. You should be able to have a brass tee fitting so you can have both installed at the same time.

The engine is the 2.5l not 3l diesel its prior to lci.
The switch is the same as seen on these forums. It did have some oil on it but not a great deal.
I havent looked at the wiring to see if oil there. .would that short them though.
I'm thinking maybe its the wiring or i have a leak somewhere...but the oil level is fine on dipstick.
Maybe its the pump or oil filter housing or valve gaskets...
Was thinkin of taking to electric specialist.

I'm assuming your saying that i should have these fitted. How easy are they to fit r they DIY or do u need a mechanic.

adambmw
http://www.realoem.com/bmw/showparts...28&hg=11&fg=30 It looks like the sensor is right near the oil filter, which should be very easy, unless there is something really in it's way. Don't know if leaking gaskets can be the problem, if the manual pressure check gave ok results. Did they hook up it through oil cap? If so, maybe the seal on the cap is bad? But then again, I'm not an expert and don't know how bad the gasket should be to cause low pressure.

Thx for your help.
I've changed the oil pressure sensor and will be changing the oil and filter today.
Spoke to dealer he says idle pressure was 1bar and load was 6 bar.
Which seems ok. Oil change is unlikely to change anything but at least it needs doing anyway.
If its the wiring then thats a difficult one to find....
Im assuming if it was the pump or anything serious the pressure reading would have been
Very low.
So my search continues for the cause and i keep driving with this message on screen.