My 82 300sd while turned off reads 3 on the oil pressure gauge.I know it is supposed to go back to 0, can anyone tell me if they have ever ran into a simular probem. If it helps, at about the same time my brake warning light also started comeing off while the car is parked and off and sometimes when I push the brake pedal while parked and off the oil pressure drops with each push of the pedal.Could this be generating from a problem with the front brake pad sensors. Thanks for any help Mike J

Mine goes down to 0 when I shut down, but it wobbles all over the place quite often at idle, a very jittery movement, I suspect the sender is dying, if it goes dead I'll just replace it. I'm not too worried about oil pressure probs, I do 2,600 mile oil changes and have a 13 month old Behr oil cooler and MB lines installed.

Since yours stays up like that on shutdown, I would suspect your gauge is dead, replacing the pod in the cluster with the engine temp/fuel/oil gauge would probably solve the problem. Does yours always sit at 3? At operating temperature idle the gauge should sit around 1-2 bar, then go up to 3 when you press the throttle. If its always at 3 its broken and should be replaced.

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50% of the time i am driving down the road with zero oil preasure... then
all of a sudden it works fine... and some times i just have a 1 or 2 oil preasure.. i figure the sending unit is dieing...

My 83 SD has the same thing going on since I bought it last year. Key on, key off, running or not the oil gauge reads 3 bar no matter what. The cluster also houses temp (works fine) and fuel (twitches big-time). Since I've put on 4,000 miles or so since purchase I'm thinking my actual oil pressure is reasonable. I think we both need to be looking at replacing that inst cluster though. Please lemme know when you do and how much it costs and where you find the cluster...I'll do the same when I get off my lazy arse.

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1983 300SD... 269,000 miles, nearly 2,500 on my B-100, Faded Grey, Ugly in an elegant sort of way...Duh-Benz


If any of this has been a blasphemy to you, then good, because it's been a blast for me to...A.Whitney Brown

I heard somewhere that the when the electric senders go bad, they make the gauge read 3 all the time. The gauge and sensor are always getting power because when the car is shut off it takes a few seconds for the oil pressure to go down to zero, so it will always read 3 if the sender is bad, no matter if the car is on or off.

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Dale

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1990 300D 2.5 Turbo -155k
2000 E430 - 103k
2014 Jeep Grand Cherokee Ecodiesel 4x4 - 11k
2014 VW Passat TDI SE - 7k Bro's Diesel
2006 E320 CDI - 128k Pop's Benz

Pre-glow - A moment of silence in honor of Rudolph Diesel

The higher the resistance in the sender, the higher the gage should read. The sender should have about 10 ohms @1 bar pressure, 180 ohms @3 bar. Hope that helps.

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

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

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

That supports my findings. The higher the resistance, the higher the gauge. A bad sensor with a high resistance will read 3 even with the car off. If one unplugged the sender, it would also read 3. Make sure that anything isn't loose.

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Dale

http://i52.photobucket.com/albums/g1...MG_2277sig.jpg

1990 300D 2.5 Turbo -155k
2000 E430 - 103k
2014 Jeep Grand Cherokee Ecodiesel 4x4 - 11k
2014 VW Passat TDI SE - 7k Bro's Diesel
2006 E320 CDI - 128k Pop's Benz

Pre-glow - A moment of silence in honor of Rudolph Diesel

The wire leading down the sending unit gets flaky with age. Sometimes it is a ten minute repair to trim the lower end off and put another connector on it.

Thanks Turbo, Pete, Old Deis...I figured the cluster was fubar but now... I noticed it still read 3 when un-plugged so wondered about that but now it makes sense. I'll trim the wire, re-plug, then test the sensor and replace if needed...it may even calm the fuel gauge, damn thing has Terrets. Thanks a bunch you guys...gotta love a place like this, advice-wise and otherwise. Drop a line Adrenelin if'n you get your'n a-workin...luck

__________________
1983 300SD... 269,000 miles, nearly 2,500 on my B-100, Faded Grey, Ugly in an elegant sort of way...Duh-Benz


If any of this has been a blasphemy to you, then good, because it's been a blast for me to...A.Whitney Brown

BTW my oil pressure functions properly when the car is being driven or at idle.The interesting thing is that once in a while after switching the car off I can depress the brake and with each push on the pedal the oil pressure drops and then bounces back up when i let go.In addition to that in order to get my glow plugs to glow i have to give the brake pedal a push before turning them on, i would say it was just a coincidence but it will happen this way 100 out of a 100 times.Is it possible that bad wireing is to blame?I did have a bit of a fire last winter.Allthough this problem only developed about a month ago.

From what I've read about instrument, um, irregularities, I would for sure be thinking an electrical gremlin. Check your grounds and maybe do what I do, which is to drive the car with the dash cluster loose so you can jiggle things while driving....you may be able to find a pattern when it acts up?? Anyone else have any idea??

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1983 300SD... 269,000 miles, nearly 2,500 on my B-100, Faded Grey, Ugly in an elegant sort of way...Duh-Benz


If any of this has been a blasphemy to you, then good, because it's been a blast for me to...A.Whitney Brown

Thanks for the help, my wiring harness was completly fried luckily it wasn't to hard to get to and I was able to patch up all the wires. My car has never ran so smoothly.

I just noticed this happening on my 81 SD... I turn the key for preglow and the oil gauge jumps to 3bar... then after driving it goes to normal after the car warms to norm op temp... 3 bar above 1500 and 1.5 bar at idle... then 0 bar on shutdown.

This morning... my brake wear light and charge light were on after startup but once I put the car in Drive, those lights went out... here we go with gremlins...

I just got the car Sunday, so it'll be a fun journey with this thing... thank god this forum exists...

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1981 300SD -- Sold Back to PO... POS
Vancouver, WA

I put a whole nother cluster in just to test at it does the same witht that one too.

I changed out the pressure sensor today and now my pressure reads 2 bar at idle.