Oil Level Sensor - PeachParts Mercedes-Benz Forum

dsvw · #1 08-09-2021, 01:04 PM

Hi,

1986 190D 2.5L here.

I removed my oil sensor switch in the oil pan, cleaned it and replaced the leaking o-ring. Now, the low level oil warning light is on in my dash. My oil level is correct.

Any ideas?
Does it need to be primed or something of that nature before it is reinstalled.

Thanks

Sugar Bear · #2 08-09-2021, 01:33 PM

Does it go out if unplugged? If yes it's the sensor. Shouldn't need to be primed. Try driving it for a while it's worth a try.

Good luck!!!

123boy · #3 08-09-2021, 01:35 PM

Should be "good to go" after r/r for the o-ring. Sounds like there may be a problem with the float. Possibly got stuck, or jammed in the down position when you had it removed?
Not exactly sure how they're constructed internally. Just did this job on my E300D and had no issues after re-installation.... pretty sure it's the same sensor (not positive). No priming or anything of that nature should be required. Maybe take it back out, see if you can hear or feel the float moving by gently shaking the sensor? Possibly spray a little brake kleen or similar in there to remove gunk, crud, etc.? Dunno, just a thought.

dsvw · #4 08-09-2021, 03:25 PM

Thanks for the advice. I will give those ideas a try.

dsvw · #5 08-09-2021, 03:53 PM

I took out the sensor and cleaned it up.
I can hear the float(?) wiggling around similar to a pcv valve so I don't think anything is jammed.

When I unplug the sensor, the light does NOT go out.

???

123boy · #6 08-09-2021, 04:51 PM

Well, I'd say that's a good sign, anyway. Not sure what else is "in the circuit" with the level sensor. You need a wiring diagram, obviously. Odd that the light stays on when the sensor is unplugged, for sure. Short to ground somewhere in the circuit? Sorry I can't be of more help. Don't know if there's a another part to that system, a small module, or part of another module, or something else. I'm sure someone on here knows. If I can locate any info I'll be sure and post it.
Have tried searching this forum? Probably a ton of info on this subject. Intermittent low oil level light om603 Probably some info in here about how the circuit works....

dsvw · #7 08-09-2021, 07:52 PM

Thank you.

dsvw · #8 08-09-2021, 08:27 PM

Problem solved. It turned out that the black wire going to the sensor had exposed wire from rubbing against something. I taped it and put wire loom over it. The light went out.

123boy · #9 08-09-2021, 08:49 PM

Awesome! Great news! Glad to hear it. "Short to ground somewhere in the circuit?" Now, on to the next challenge....

Sugar Bear · #10 08-09-2021, 10:04 PM

Good work!!! Glad to see diagnostics in use.