'82 240d 153k:

Had low oil pressure @ idle ~.5bar; revved=3bar+ (normal)

Obviously a spring problem. New oil pump solved it.

Hard to believe this happened at only 153k miles...

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1982 240D auto 152k
1984 380SL 113k
2015 Ram 2500 6.7 Cummins
Previous:
1985 300DT
1984 190D 5sp Euro

If the two 6mmIDx10mmODx2mmW O-rings at the Bottom of that Tube on the Oil Filter Cap have not been changed you can have the same symptoms.

I am not sure istalling a New Oil Pump proves it was the Pressure Relief Valve Spring. If you only replaced the Oil Pump that proves there was something a miss in the Oil Pump and that may have been the Spring or something else in the Oil Pump.

If you replaced the Oil Pump and also replaced the 2 O-rings at the bottom of the Oil Filter Tube at the same time; before you ran the Engine that makes it less certain it was the Oil Pump.

Otherwise a Perfect Fix.

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84 300D, 82 Volvo 244Gl Diesel

FYI-
I had already replaced those two small oil filter O-rings per your previous posts in other threads.
It was of no help. That was the first thing I did.

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1982 240D auto 152k
1984 380SL 113k
2015 Ram 2500 6.7 Cummins
Previous:
1985 300DT
1984 190D 5sp Euro

My first 240D - a tired 1982 with automatic tranny - had hot-idle oil-pressure readings around .5 bar in drive - going up to .8 to 1.1 in neutal. Changing those oil-filter O-rings made no difference.

Happy Motoring, Mark

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DrDKW

I saved this thread to My Notes so if someone else has the same problme I can post it for them; but, while I remember reading them I had never saved any of the Threads/Posts where changing the O-rings raised the idle Oil Pressure.

I also remember reading many Years ago that the NA Engine Oil Pumps had problems with the Relief Valve Springs and the Relief Valve but I did not save any of those threads either.

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84 300D, 82 Volvo 244Gl Diesel

On both of my Mercedes, I have managed to raise the oil pressure by doing very frequent oil changes meaning like ever 1-2k miles. I had the problem where after freeway driving my idle pressure was very very low....its seems that something gets gunked up over time......on my other diesel, I even managed to rid the motor of blo by....by frequently oil changes and valve adjustments....

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