Change the oil to a known good quality oil. Verify the pressure at startup and when hot. It should go to 3 bar on cold start and after 5 minutes probably indicate 2 to 2-1/2 bar at idle. Another 10 minutes of driving should get the oil to operating temperature and pressure should not dip below 0.7 bar at idle. That I believe is the MB spec. You should be able to get the pressure above 1 bar with an increase of about 200 rpm. The pressure should ALWAYS read 3 bar while driving (above ~1500 rpm).
I'd try to have someone verify your pressure transducer is giving the correct output to your gauge. But in the meantime, keep one foot on the gas and always give it enough gas at idle to keep the pressure at or above 1 bar. It is extremely important that you propery lubricate that engine. You may be losing oil from the main bearings or your oil pump is not delivering enough oil.
'05 E320 CDI - 86,000 miles
'86 300SDL - 360,000 miles
'85 300SD - 150,000 miles (sold)
'89 190D - 120,000 miles (sold)
'85 300SD - 317,000 miles (sold)
'98 ML320 - 270,000 miles (sold)
'75 300D - 170,000 miles (sold)
'83 Harley Davidson FLTC (Broken again) :-(
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2005 Tzitzu (Griffon)
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