Just wanted to share my experience.
Mine runs at 4 bar but does go less when idleing. I had an oil change and synthetic oil was put in it which made my oil pressure gauge go up and down like a rev counter. I was then told by a different commercial vehicle mechanic it should have heavy duty turbo diesel oil and not synthetic unless it had been run on synthetic from new, so got it changed back and its ran better since. Interesting though my pressure has gone down too recently so will be interested to read your replies
mechanically useless!, October 2009
