yesterday I checked my oil and it seemed pretty low, below the red plastic min marker. I usually check it frequently, but I neglected to for a week or so, assuming that my low oil light would come on. Well, it never did. Is there a way to check if the sender is faulty? (multimeter or something?) I know the light itself works, b/c it comes on when I turn the key to position 2.

I already did a search on this, and surprisingly I could not find anything.

Thanks for your time.

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headrivenoise... listen.

Yes it is just a switch controled by a float.

Remove wire plug and test for continuity. Oil level full should be open loop or very high ohm reading on the tester and low oil level or removed from pan and rite side up should show moderate ohm reading.

Yes, that would be a valid test, or simply turn on the key the next time you have the oil drained at oil change time and see if the light comes on. I guess it goes without saying that you should not turn the key to the start position, only to the ON position.

Good luck,

When I removed my level sensor to replace the gasket that was leaky I was surprised at how low the oil would have to go before it would "trip". Mine is an E300 diesel which holds almost 9 quarts of oil. When full, the oil level is about a pint above the sensor's mount (in other words, about a pint spills out when you remove the sensor. Then, it would appear that the level would have to drop at least another inch before the float would move and maybe another half inch to inch before the level sensor would trip. I would say that means on my car the oil would have to be down about 2-3 quarts from full or 1-2 below add on the dipstick before the level sensor would trip. I don't think that MB designed the level sensor in order to let you know when to add oil necessarily, but when the level is so critically low that you MUST attend to it. Apparently the diesels will shut down when the low oil level sensor trips. I don't know if that's true of the gas models but you wouldn't want it to do that if you were simply a quart low, I wouldn't think.

Today's modern cars without dipsticks would have a more refined electronic level sensor that actually tells you to add oil when it is just low...but the older warning systems seem to be just to prevent catastrophic damage...like the "belt and suspenders" approach.

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Marty D.

2013 C300 4Matic
1984 BMW 733i
2013 Lincoln MKz

dirtysocks, AFAIK and as mentioned by others the oil level needs to be dangerously low for the low oil level sensor to light. It certainly won't light if the engine is only a quart or so low. Larry Bible makes an excellent suggestion for testing that the level sensor is functioning. If you use an oil/liquid extractor when changing your oil you might check the function of the level sensor as you suction out 1 quart, 2 quarts, etc. so that you know at what specific level the sensor energizes the trouble light on the dash. Too bad this thread wasn't posted before late yesterday or I would have verified the sensor function when I changed the oil in our 1991 300CE the day before.

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Fred Hoelzle

Thanks Marty for mentioning this part has a gasket which can leak. Yesterday. I noticed wet oil around the oil sender. Could someone post or describe removal instructions for a w124 ( 88 300ce). Thanks.

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87 300e (white/black; amg body kit)
88 300ce (red/cream; amg body kit)
93 300ce cabrio (white/blue/blue top)
93 300ce cabrio (black/grey/black top)
98 ml 320 (totaled @ 137,000 miles)
99 clk320 (black/grey/black top)