So driving the '86 300SDL for the last few days, I've noticed an irritating trend with the "Low Oil" warning light. Once the engine has reached operating temp, it will come on with any sort of long sweeping turn, or any sort of hill climbing.

When the engine is cold, this never happens, only when engine is hot. Oil level is fine, about 1/8" below the "Max" fill mark. The engine is burning a small amount of oil, but in ~500 miles, the oil level hasn't moved an appreciable amount (not enough to tell a difference in level).

So the question.....do the sensors wear out? Is it just a float or something in there that could be coming apart? Why would temperature have anything to do with the behavior of the level switch? Should I be looking for something else instead of the level switch?

Help! Having that flashing light coming on every 30 seconds is about to drive me nuts! I live in an area that's nothing BUT hills, so this is truly an irritating problem, especially considering the oil level is fine!

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Current stable:
1995 E320 149K (Nancy)
1983 500SL 120K (SLoL)

Black Sheep:
1985 524TD 167K (TotalDumpster™)

Gone but not forgotten:
1986 300SDL (RIP)
1991 350SD
1991 560SEL
1990 560SEL
1986 500SEL Euro (Rusted to nothing at 47K!)

I'd prolly change the sender.

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[SIGPIC] Diesel loving autocrossing grandpa Architect. 08 Dodge 3/4 ton with Cummins & six speed; I have had about 35 benzes. I have a 39 Studebaker Coupe Express pickup in which I have had installed a 617 turbo and a five speed manual.[SIGPIC]

..I also have a 427 Cobra replica with an aluminum chassis.

Oil sloshes more easily when hot. Just unplug it. I've spent most of my adult life driving cars without a low oil sensor and I've never run an engine out of oil.

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1977 300d 70k--sold 08
1985 300TD 185k+
1984 307d 126k--sold 8/03
1985 409d 65k--sold 06
1984 300SD 315k--daughter's car
1979 300SD 122k--sold 2/11
1999 Fuso FG Expedition Camper
1993 GMC Sierra 6.5 TD 4x4
1982 Bluebird Wanderlodge CAT 3208--Sold 2/13

This is a common issue with these OM 60X engine's sensor.

Using correct oil viscosity?

Currently running Dino Rotella 15W-40, so that shouldn't be an issue.

So is the sensor worth replacing, or will it continue to cause false warnings once replaced? Since it was there from the factory, I'd like it to function properly, but if it's just going to be a PITA, I have no problem unplugging it and ignoring its existence. I've never run a car out of oil, and I have no intention of doing it to this one.

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Current stable:
1995 E320 149K (Nancy)
1983 500SL 120K (SLoL)

Black Sheep:
1985 524TD 167K (TotalDumpster™)

Gone but not forgotten:
1986 300SDL (RIP)
1991 350SD
1991 560SEL
1990 560SEL
1986 500SEL Euro (Rusted to nothing at 47K!)

Swap it during your next oil change. My sensor failed in my W210 and kept giving warnings.
Part costs about $50 at Pelican.

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The OM 642/722.9 powered family
Still going strong
2014 ML350 Bluetec (wife's DD)
2013 E350 Bluetec (my DD)

both my kids cars went to junkyard in 2023
2008 ML320 CDI (Older son’s DD) fatal transmission failure, water soaked/fried rear SAM, numerous other issues, just too far gone to save (165k miles)
2008 E320 Bluetec (Younger son's DD) injector failed open and diluted oil with diesel, spun main bearings (240k miles)

1998 E300DT sold to TimFreeh
1987 300TD sold to vstech

I would discouraging taking the time to change the sender if this is the only symptom. My OM603 oil warning light comes on when I am at at stop on a road with a lot of side slope (aka crown). I have a new sender, new oil, correct level, etc. I have learned to simply ignore the light at those instances.

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1968 220D, w115, /8, OM615, Automatic transmission.
My 1987 300TD wagon was sold and my 2003 W210 E320 wagon was totaled (sheds tear).