Sybill, car of many personalities, has developed an annoying habit. Periodically the 'low oil' light will illuminate for no apparent reason. The first time it happened I freaked-out, killed the engine and dashed for the side of the road only to find a normal oil level on the dipstick.

I searched the forum but didn't find anything on this subject. Any suggestions?

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Never a dull moment at Berry Hill Farm.

There is a 20 Seconds or so time delay built into the oil light dash panel circuit board. This delay was designed to allow you to make sharp turns, where the oil temporarily moves to one side of the oil pan, or the other, without activating the low oil light. I think it was specifically designed for sharp right turns, but it could be left turns, can't remember.

In any event, this circuit tends to fail, reducing the delay to Zero Seconds, and activating the low oil level light when you make a turn. I don't know of an easy fix, but maybe someone else does.

The point is if the low oil level light comes on during, or immediately after a sharp turn, than most likely this is the problem. Otherwise you need to look elsewhere.

Phil

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'95 E300 Diesel, 264,000 Miles. [Sold it]

I saw something about this in STAR magazine recently (but can't remember which month/year). If it does this more when cornering or in curves it is a faulty oil level sensor. This occurs more in the E class diesels for some reason.

From my reading here, it seems that there is an "averaging" circuit in this system that goes bad with age. The way the system is supposed to work is the light will not come on until you have a continuous low oil situation for some period of time - say 30 seconds or so. This time-day or averaging circuit goes bad and then the light will come on with a much shorter period of low oil.

So, what you may be seeing is a short "low-oil" condition as measured at the sensor when you make a fairly sharp left turn. The sensor is on the side of the engine, driver's side. So a left turn throws oil away from the sensor.

In my 1987 300D, I start to get the low oil light when I'm about a quart down from "full". So its still quite useful to me. But the oil is not really "low" at that point.

Ken300D

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1982 300D at 351K miles
1984 300SD at 217K miles
1987 300D at 370K miles

Thanks all, for the input!

The warning light illumination is pretty erratic and doesn't seem to be associated with any cornering activities. I should get under there and take a look at the connections on the sensor too.

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Never a dull moment at Berry Hill Farm.

One more reason to get back to the 123 body style....
Put a mechanical oil pressure guage in there.... then you don't have like four failure modes... all of which leave you with NO indication... and you don't even have a " press to test" situation...
That 'averager' is just like the timer circuit on Glow Plugs... it should have been a ' press this button' for 20 seconds ( or whatever it takes ) before using the key to engage the starter.
Might have worked great at the start... but 20 years along the way some of these things don't make sense trying to retain on our cars...

And I suppose next you'll be offering to take Sybill 'off my hands' for a low price...just to save me the inconvience.


Or, how about a big knob you pull on until a thingus in the dashboard glows orange?


Gorilla Knob

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Never a dull moment at Berry Hill Farm.

Yes, you are correct.. they should never have changed from that design....

I love my super simple 123 240d and would not consider other chassis.....

OK Randy, with specific reference to the one below, I've found the the deal with that light is as follows:

If you keep the oil level above the 1/2 way mark, the light won't illuminate.

But, your oil consumption will climb a fair amount with the oil that high.

If you let it drop to around the 1/4 point, it is "close" to triggering the light.

It may go off on downhills and go on during an uphills. It won't come on until the engine is sending oil to the cooler. Basically it becomes a PITA.

If you let it drop to the "add oil" mark, which is where I like to run it to keep the oil consumption down, then it's on quite a bit.

It's sensitive to the attitude of the vehicle, and this one is down in the back, so, I'm hoping that this is part of the problem. I'll correct it in the spring.

Let me know if yours is similar.

leathermang, you definitely should drive an SDL...

I had a mechanical oil gauge on my '79 SD, leaked at one time with the PO, I'm sure that wasn't messy. Plus, all I need to do is unplug a couple wires and the cluster is out! No rags to cover the line or speedometer cable to break (also happened on my SD)

I will agree that a 123 is simpler, but I think the newer 126 is well worth it.

Thanks
David

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2000 Honda Accord V6 137k miles

1972 300SEL 4.5 98k miles

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He rode in mine but complained about the seats...Greg hates electricity. He wouldn't use the adjustment controls.

Looky! This one makes 2700 posts!

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Never a dull moment at Berry Hill Farm.

The glow plug circuit has an electrolytic capacitor which occasionally fails with time. Some do, some don't. I would look for a capacitor in that circuit - might be an easy fix, but electwicity and me don't mix too good. ever since I heard it could leak I've been kept busy putting tape over the outlets in the house so it doesn't leak out

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'82 300SD - 361K mi - "Blue"

"Good judgement comes from experience. Experience comes from bad judgement."

listen, look, .........and duck.

Brian,
Your description fits my sdl exactly. Once the level drops 1/2 to 2/3's the light pops on depending on the attitude of the car. I find it very annoying. A short term fix I'm considering is to disconnect the light I found out the hard way not to add a whole quart at that point It just blows or burns it out.
Dave

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1986 300SDL

I'm having trouble with oil consumption on mine. On the latest 5K oil change, the consumption is up to about 2.5 quarts. I'm trying to keep it right on the low mark to reduce this consumption. It seems like it's successful, but, I'm sick of the damn light. It's like a christmas tree.