Oil pressure light on!!!

[jex]

This may be totally unrelated...but yesterday I pressure washed my motor. Nothing serious, just a quick spray.

Anyways, I hop in my car today and the oil pressure warning light is staring back at me! I shut the car off. Started it again a few seconds later and let it idle. The light slowly went off. After it went off, I revved the engine a few times.....then it came right back on and wouldnt go off.

Any thoughts??? If there is any way possible I need to fix this tonight...I'm suppose to make a 2.5 hour trip back home tomorrow!

Im hoping its a switch...anyone know how to check? My Bentley is at home!!!!


btw...car is a 91 318is.

[Jordan]

Same exact shit happened to me right after I got my 91 318iS, and pressure washed the engine bay.

Replacing the switch fixed it, its like $6... do it.

Bench testing the switch is difficult.

[jex]

Ok...how can I check the oil pressure?

I'll replace the switch, but it will be a couple days before I can get the part.

[Jordan]

Have you checked your local Autozone etc? All those local to me (and I live in the sticks) either stocked an off brand, or could have one next day.

Start the engine, let it idle. Pull the oil filler cap off. If oil drops splash out onto the valve cover you are most likely just fine. Other than that you can buy a mechanical pressure gauge, remove the pressure switch, and screw it into the switch port to measure.

If you don't have any oil pressure, even at idle, the engine will be LOUD. The timing chain will be loud, and the lifters won't have sufficient pressure. You'll know you don't have pressure just by the sound..

Seriously though I'm willing to bet what happened to me is exactly what happened to you. I went through a lot of troubleshooting being extra safe for nothing.

[jex]

Ok...I'll check out auto zone, napa, etc.

I think the switch is probably the culprit (I really hope so).

Thx Jordan....really appreciate it!

[jex]

Sure enough...it was just the switch. Easy fix :) :)

[Garageaholic]

Jex, how old was your switch? I have the same problem in my M30 (same switch FYI)...

Since my coolant reservior is right there (back of cylinder head), coolant was spilling onto the switch throughout my bleeding process.... now my light is on!

the thing is that my switch is brand new.