Hi folks. I am a DIY'er and am hoping to fix an issue I am having with my Mini with your help. I drive a MC40 (R53).


Here is the details: I start the car, no light, car runs fun, I mean fine. I start driving and everything is fun. When I stop for a stop sign or at a light or to park, the oil light comes on. While I am driving the light is off, if I push in the clutch and the clutch is depressed long enough, the engine RPMs drop (like they are supposed to), unless I re-engage the clutch the oil light comes on. If I drive the light goes off again. Driving + oil light off, idling = oil light on.


Here is the real trick, after driving if I stop the oil light is on, if I turn the car off and on the oil light goes away during idle. I let the car idle for a few minutes and everything is fine. I drive a bit and the oil light starts coming on again during idle. I stop and turn the car off and on and the oil light stays off during idle until I drive again.


I haven't hooked up my code ready yet but I have a feeling it won't reveal much.


The car is not low on oil. I am 100% on that.


My thoughts:
- Clogged oil filter.
- Smashed oil filter (from the last place that did an oil change over tightening the oil filter cap).
- Oil pump going bad.
- Clogged in the oil lines somewhere.


Just for some info, this is a used engine that was put in the car a few months ago (old engine was overheated and would not hold a head gasket)


Has anyone else had this issue or have an idea of what might cause this?

 

I had a problem simular to that when I first got my mini. The oil like would come out at weird times.....sometimes when I would take off from a light, some times when I was going around a corner, some times when I would rev up the motor....but never when it was just idling int he garage.

I checked the oil pressure with a gauge and it was just fine.

Turned out to be the wire coming from the oil pressure sensor that was shorting out on the exhaust shield....on the back side of the motor down by the starter. When ever the motor would move, or twist......it would short out the wire, and the oil pressure light would on. I found the bare spot in the wire, repaired it...problem solved

Take the heat shield off on the back side of the motor, and then there is another shield that covers the starter. The wire runs underneath that shield that covers the starter.

 

Sounds like the oil pressure sensor/switch needs replacing.

 

+1 +1 on checking the sensor wire, make sure it is free of damage and that it is not grounding out.

...and if you have the ability to replace the sensor with an adapter with analog gauge you can check the physical pressure of your oiling system (oil pump).

Best of luck.

 

If you haven't changed your oil and filter, do so now. If the problem is present after the change, look at your sensor and sensor connector. They're near the oil filter housing. If those are fine/replaced, you're going to have to replace the pump, which is a bigger deal work-wise. Don't wait: this is important to sort out quickly.

 

Check the oil pressure switch. 12617513068

http://www.ecstuning.com/Search/SiteSearch/12617513068/



Pull the oil filter out and see whats going on and change the oil and filter.

 

If it was me...the first thing I would be doing in screwing the oil pressure switch, and hooking up a mechanical oil pressure gauge to verify how much oil pressure you are actually getting.....then do from there. You should be able to put up an oil gauge kit pretty cheap and most auto parts stores. At least that will tell you if it's a false alarm or not.

 

Thanks for the help guys.


I am going to start with the oil change and filter, then the sender and wiring, then pump.


I have a MC40 so I have a gauge, but the damn thing hasn't worked since I got the car. Guess it's time to get that fixed to make sure the oil pressure is there and to help trouble shoot.


Anyone know how to trouble shoot an oil pressure gage?

 

I took a look at the sending unit and there was oil everywhere. I can't tell if it's coming from the unit and the unit is bad or if it's the seal and the oil is making the unit short. I was going to replace the sending unit but now I think I am just going to put on a mechanical/analog oil pressure gauge.

 

Mechanical gauges are okay but think of hot oil and a leak in the cabin of the car. My opinion is an electrical gauge

 

You sell one I presume. Can you provide a link?

 

I have a mechanical gauge in my car and I havent had any issues. I originally had this problem and I decided to remove the idiot light.

Additionally, the light will not go off in the absence of a sensor. I cant remember the size of the port on the oil canister, but its a standard brass fitting size. Take the removed sensor to lowes or home depot and use their sizing guide to find an appropriate brass fitting/reducer.

 

Anyone know the size of the wrench needed too unscrew the oil pressure sending unit? It is larger than the biggest fixed wrench I have and I can't seem to fit any adjustable wrenches. And if anyone has tips on getting this thing out I am open ears.

 

I wonder if it's worth checking the crankshaft end float. I would be.

 

I bought a replacement sending unit from ECS. The original receive date was the 21st. I got notice it had changed to the 26th and I was going to rent a gauge over the weekend to check that it was indeed just the sensor. Ended up getting it in the mail on the 23rd and installed it yesterday. Drove around, all good, drove to work today, no idiot light. Looks like it was just the sender. Thanks ECS.


Just a side note. Monument has these same units for $25. After shipping they come out to the same cost, however, ECS's sender is BMW original and Monument was some French manufacturer who I have bought parts from before and had them fail.

 

" Looks like it was just the sender. Thanks ECS. "

You are welcome.

 

Sorry for reviving an old thread, but what is meant by the sending unit? Whenever I search for it, the results are for the oil pressure switch. Is this correct?

 

Yes, thats the sending unit.

It's been a while, but IIRC i replaced mine with an actual mechanical oil gauge. Im not sure why the light kept going off, as my pressure was fine. The light should not come on if the sending unit isn't connected. The threads are standard NPT (3/8 and 1/8), so you can buy a brass fitting to connect a flexible oil line to a mechanical gauge. I highly recommend it so you can know the actual oil pressure, rather than relying on the idiot light.

This is a slightly newer model to the one I used, and it worked great:
If you go this route, you'll have to punch a small hole in the firewall to bring the plastic tube into the cab. I used the same location the electrical came in. It was easy to get to, and worked great.

Feel free to reply or message me if you need any advice.

EDIT: Here is a GREAT step-by-step that I used. I used different parts, obviously, bit the guide was invaluable. http://www.billswebspace.com/R53GaugeInstallation.htm