BMW: Oil pressure sensor warning 89 525i m20 engine, oil pressure switch, pressure sensor

Question
Hi Josh,

My dash warning screen has been indicating an oil pressure sensor warning. If you remember my dash instruments have been intermitant but the oil presure sensor warning has come up today.

I have an m20 engine, where is the oil pressure sensor located and how dificult is it to r&r?

Any r&r intructions would be great!!!

Thanks again Josh.

Jose

Answer
Jose,
 These cars have an oil pressure "SWITCH", not a sensor.  A sensor would tell the computer/instrument cluster HOW MUCH oil pressure is there.  A switch just turns the light on if pressure falls below a certain level.  

 First, check your idle.  If the engine is idleing too low, it will not spin the oil pump fast enough, and it will show that there is low pressure, when the pump is fine.  So your car should be idleing at ~750rpm.
 If the engine is idleing that high, then the switch is probably the culprit.

 The switch is on the side of the block, underneath the exhaust.  Look underneath the car, and find the oil filter.  Got STRAIT DOWN, almost to the oil pan.  You cannot miss the sensor.  There are two different types of sensors as well, so it's best to carry yours with you when you get another one.

 Good luck
 Josh