Subman,
Check your owner's manual. It'll tell you that oil pressure may safely go as low as 0.3 bar at idle. Mine tends to go to 0.5 bar at idle, in gear, in hot weather (if I'm using conventional oil). The key is it should peg the needle by about 1800 RPM.

FWIW, my oil pressure NEVER goes below 1.0 bar since I switched to Mobil 1 15W-50 oil. According to MB, low idle pressure is nothing to worry about, but it DOES make me feel better to see those readings a little higher!

__________________
Steve
'93 400E