Oil light coming on intermittently... - PeachParts Mercedes-Benz Forum

MercFan · #1 11-30-2009, 11:30 PM

While driving the car today (300SDL) trying to warm it up for a first oil change I had the oil warning light come on several times - each time for just few seconds (5-10 seconds) and it would turn itself off. First time on a highway driving 60 mph on a straight away, it went out in about 10 seconds; several minutes later it came on again. I turned the car around, checked under the car to make sure I wasn't hemorrhaging oil under the vehicle - I wasn't, so I proceeded to drive home. It came on once again before I turned into my subdivision - so I gently coasted home and it went away again. I changed the oil to a fresh new Rotella T 15W40 and will be keeping an eye on it very closely.

I just wonder if this warning light was a result of an improper oil level, or possibly an 'oil minder' light warning me that it's time to change the oil!?
Not sure they had such technology back in 1987.

All this time the oil pressure was at the very top mark - no drop in oil pressure was ever observed... strange... very strange....

CANDIDE · #2 12-01-2009, 01:07 AM

Quote:

Originally Posted by MercFan

While driving the car today (300SDL) trying to warm it up for a first oil change I had the oil warning light come on several times - each time for just few seconds (5-10 seconds) and it would turn itself off. First time on a highway driving 60 mph on a straight away, it went out in about 10 seconds; several minutes later it came on again. I turned the car around, checked under the car to make sure I wasn't hemorrhaging oil under the vehicle - I wasn't, so I proceeded to drive home. It came on once again before I turned into my subdivision - so I gently coasted home and it went away again. I changed the oil to a fresh new Rotella T 15W40 and will be keeping an eye on it very closely.

I just wonder if this warning light was a result of an improper oil level, or possibly an 'oil minder' light warning me that it's time to change the oil!?
Not sure they had such technology back in 1987.

All this time the oil pressure was at the very top mark - no drop in oil pressure was ever observed... strange... very strange....

I'm having the same problem with my sdl. In addition to false low oil indications, it leaks from the center of the sensor. The sensor is on the driver's side of the oil pan. I'm changing the oil tomorrow and will replace the sensor.
I don't know if an open circuit causes the light to come on, if it does, then you might have a loose/intermittent connection.

MercFan · #3 12-01-2009, 08:45 AM

Quote:

Originally Posted by CANDIDE

I'm having the same problem with my sdl. In addition to false low oil indications, it leaks from the center of the sensor. The sensor is on the driver's side of the oil pan. I'm changing the oil tomorrow and will replace the sensor.
I don't know if an open circuit causes the light to come on, if it does, then you might have a loose/intermittent connection.

Mine doesn't seem to be leaking, but the wires have lost their rubber coating... I need to check the connection underneath.

C Sean Watts · #4 12-01-2009, 08:45 AM

Quote:

Originally Posted by MercFan

While driving the car today (300SDL) trying to warm it up for a first oil change I had the oil warning light come on several times - each time for just few seconds (5-10 seconds) and it would turn itself off. First time on a highway driving 60 mph on a straight away, it went out in about 10 seconds; several minutes later it came on again. I turned the car around, checked under the car to make sure I wasn't hemorrhaging oil under the vehicle - I wasn't, so I proceeded to drive home. It came on once again before I turned into my subdivision - so I gently coasted home and it went away again. I changed the oil to a fresh new Rotella T 15W40 and will be keeping an eye on it very closely.

I just wonder if this warning light was a result of an improper oil level, or possibly an 'oil minder' light warning me that it's time to change the oil!?
Not sure they had such technology back in 1987.

All this time the oil pressure was at the very top mark - no drop in oil pressure was ever observed... strange... very strange....

Let me guess LEFT turn = light, RIGHT turn = no light?

You're correct about the service light (at lest for the 603s)
If this light was the oil LEVEL sensor, there were design changes to both the oil pan and sensor circuitry along the years. It's in the factory service CDs if you have them. As long as you have a good level on the dipstick and good pressure on the needle it's a false alarm.

i-osprey · #5 12-01-2009, 09:50 AM

My 602 does the same thing.

I was told that there is a delay mechanism/circuit that is supposed to keep the light from coming on unless there is a prolonged signal telling you the oil level is low.

When you turn it senses no oil but only for a few seconds.

There is supposed to be something built in that prevents false warning lights but apparently they can fail.

Mine will also do it under hard braking.

Shawn T. W. · #6 12-01-2009, 10:08 AM

Quote:

Originally Posted by MercFan

First time on a highway driving 60 mph on a straight away, it went out in about 10 seconds; several minutes later it came on again.

All this time the oil pressure was at the very top mark - no drop in oil pressure was ever observed... strange... very strange....

Not a issue of turning, but still strange . . .

I'd try to confirm the presure gauge is actually working right.

MercFan · #7 12-01-2009, 10:11 AM

Quote:

Originally Posted by C Sean Watts

Let me guess LEFT turn = light, RIGHT turn = no light?

Not really... for me the light kept coming on on a straight away - no turns. Drove to work today about 15 miles in the same car after a fresh oil change and the light never came on.... Could it be that the old oil was causing the light to come on?! THought the oil level was in between the marks at the time...

dagObx · #8 12-01-2009, 01:22 PM

I have this same issue with my '87 300DT. My indy says its the sensor in the oil pan going bad - replace the sensor & problem fixed. I have a replacement, but haven't put it in yet. Will report back when job is done, hopefully in a couple of weeks.

Must be a 603.xxx thing.....

MercFan · #9 12-01-2009, 01:26 PM

Quote:

Originally Posted by dagObx

I have this same issue with my '87 300DT. My indy says its the sensor in the oil pan going bad - replace the sensor & problem fixed. I have a replacement, but haven't put it in yet. Will report back when job is done, hopefully in a couple of weeks.

Must be a 603.xxx thing.....

Do you have to pull the pan to replace it?! And if so, can you pull the pan out while keeping the engine in it's comfy place, or does that have to come out first...

?

Jeremy5848 · #10 12-01-2009, 02:47 PM

You can replace the sensor (float switch, really) without removing anything but the belly pan and the oil. Change the sensor next time you change oil.

My '96 E300D (W210, OM606NA) has this problem even though the sensor has been replaced. The warning occurs after the car has been driven a few miles and does not repeat after the warning is canceled (digital display in the 210) until the engine is turned off and restarted. I suspect a problem in the instrument cluster circuitry which, unfortunately, is all surface mount IC technology. For the moment I'm ignoring it but would really like to get it fixed some day.

Jeremy

MercFan · #11 12-01-2009, 02:52 PM

Quote:

Originally Posted by Jeremy5848

You can replace the sensor (float switch, really) without removing anything but the belly pan and the oil. Change the sensor next time you change oil.

Great - I might try cleaning it first... and then replacing as the last resort.

Jeremy5848 · #12 12-01-2009, 07:11 PM

Quote:

Originally Posted by MercFan

Great - I might try cleaning it first... and then replacing as the last resort.

There really isn't anything to clean. Just make sure that the connector (one wire) fits tightly onto the sensor and isn't damaged, shorting to ground, etc.

bigblockchev · #13 12-02-2009, 06:54 PM

The engine oil level senders are sometimes a bit overly pessimistic. MB even has a lengthy diagnosis procedure. Does this have anything to do with your recent repair of the stripped oil drain bolt? If it doesn't clear up when you fill the sump up to the fullish mark then consider changing the sender. Cheers Dan

MercFan · #14 12-02-2009, 07:30 PM

Quote:

Originally Posted by bigblockchev

Does this have anything to do with your recent repair of the stripped oil drain bolt? If it doesn't clear up when you fill the sump up to the fullish mark then consider changing the sender...

Yes, it might - though so far it has not yet come on since the fresh oil change. Time will tell - thx