I have an issue that has puzzled me for a couple of weeks. The oil pressure light comes on when I speed up, brake hard, or turn left. The pressure gauge shows 3 bar when driving and 1.5 when idle. The dipstick shows almost full. I had the oil pressure sending unit replaced last year due to a leaking seal. I read the FSM and it stated that the dash electronics sense when the oil level drops below the sending unit but it doesn't illuminate the light unless that condition lasts for more than 30 seconds.
Why would the light come on when the pressure gauge shows 3bar?

Thanks,
clint

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81 300D N/A 130K miles (Nelly)
87 300D Turbo 80K miles (The Scalded Dog...because it runs like a scalded dog)
95 e320 Wagon 104K
2003 Sprinter 47K miles.
1999 Tandem Bicycle
One beautiful low miles wife (who likes diesels) (that's my wife holding the sign)

My son and I fixing Nelly's odometer

Oil pressure light? What is this oil pressure light of which you speak? As a w123 owner I wouldn't know.

Ok, someone with a real response can shime in now.

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Ralph

1985 300D Turbo, CA model
248,650 miles and counting...

On the 124, its an amber lamp just to the right of the brake sensor light.

__________________
81 300D N/A 130K miles (Nelly)
87 300D Turbo 80K miles (The Scalded Dog...because it runs like a scalded dog)
95 e320 Wagon 104K
2003 Sprinter 47K miles.
1999 Tandem Bicycle
One beautiful low miles wife (who likes diesels) (that's my wife holding the sign)

My son and I fixing Nelly's odometer

Check your oil level. The condition you described happens when the oil pump gets starved, and cannot maintain pressure. This usually happens if the oil level is low, or if the oil pan does not have baffles to keep the oil from sloshing around when cornering, braking, etc.

This is a common malfunction with the early model 124. Some component on the circuit board that operates this feature has gone haywire. Unless one of you electronics wizards can figure out exactly which component has gone TU, the only thing you can do is swap in another fuel/oil/coolant guage cluster (they're all integrated with the circuit board). That's what I did to fix the problem.

I read a couple of days ago that there are various length dipsticks out there. It is a long shot, but if your dipstick is too long then you just THINK you are showing almost full.

Anyone know how to check which length should be in that car?

-Jim

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1995 S350D, Green with black leather interior.
Bought January 2008 w/ 233,xxx miles.
I did 22,000 miles during the first year of ownership.

That sending unit goes bad often too, it's about $20... cured my problem.

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I'm not a doctor, but I'll have a look.

'85 300SD 245k
'87 300SDL 251k
'90 300SEL 326k

Six others from BMW, GM, and Ford.

Liberty will not descend to a people; a people must raise themselves to liberty.[/IMG]

Ya, I replaced that too, but all that cured was the oil leak from the center of the old one.

Most likely the electronic module, wherever it is The sensor does not as someone said mean the pump is being starved!
The float tends to drop on what I figure are left turns as that side dives doesn't it?
I also keep the oil at mid-mark because there were reports that oil consumption increases in the 603 engine when it is at or above the top (full) mark.

This 124 feature is nice and as long as your car doesn't use lots of oil I'd live with it until you find a used module someday. There was an update I believe that changed the time constant in the module early on in the production cycle.
As for the dip stick, somewhere I believe there was a factory change, the dealer can run your VIN# and tell if its had the recall if there is one applicable, etc. I'm sure they would be happy to sell you a new module too

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'95 E320 Wagon my favorite road car. '99 E300D wolf in sheeps body, '87 300D Sportline suspension, '79 300TD w/ 617.952 engine at 367,750 and counting!

I think diesel die hard has got it. From your description the time constant or delay circuit has a faulty component so you get instant light the moment the oil level surges or whatever. Normally the light delay circuit stops this happening unless the condition lasts say 30 seconds. By that time normally the oil level has returned to normal so you get no light. Either get a component perhaps out of a junker or other than the anoyance it will do no harm as is. You still will be able to use it as a warning device as the light would just still stay on continiously if you had a real problem.

Right on. The delay on newer units is 45 seconds, it is set to overlook the time one might be in a long turn or something that sloshes the oil over to one side of the sump. (I can't imagine driving in a hard turn that long unless on a race track!)
I bet a capacitor in the module dried out, same as what makes tachs and cruise control electronics quit.

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'95 E320 Wagon my favorite road car. '99 E300D wolf in sheeps body, '87 300D Sportline suspension, '79 300TD w/ 617.952 engine at 367,750 and counting!

Thank you all!
The electronic component of the light (time delay) is what I thought had gone wacky. I topped off the oil last night and I still have the same problem. I am thinking that it may actually be the sending unit. The reason I say this is that I don't recall the problem before the sending unit was replaced last year. The reason for replacement was that it leaked like a sieve.
Anyway, thank you all for your advise and analysis.

clint

__________________
81 300D N/A 130K miles (Nelly)
87 300D Turbo 80K miles (The Scalded Dog...because it runs like a scalded dog)
95 e320 Wagon 104K
2003 Sprinter 47K miles.
1999 Tandem Bicycle
One beautiful low miles wife (who likes diesels) (that's my wife holding the sign)

My son and I fixing Nelly's odometer