oil pressure problem

my 300 tdi has done 230000km the oil pressure light was coming on after a long run at idle, i have put an oil pressure gauge on and it is idling at 44psi cold and 20psi hot, when running at temperature it is holding 40psi except at idle.
thought that it may have been the oil thermostat, so i removed it to get full flow through the cooler. i have had the stethoscope on the engine and it runs as smooth as they come with no rattles or bearing noise, it does not suffer any loss of power. anyone got any ideas.

Hello

I have a similar problem, mine is 55psi at worm up, 45 at 3000rpm when warm, but drops down to 16 when idle and warm Is this ok? I do have a power issue and was thinking it was my injector jump, could this have something to do with it?

many thanks
Mike

hi mike, your injector pump should not affect oil pressure, i thought it may have been the oil pump, but no one has come up with any other ideas.
bill

presuming you've done the oil and filter change?
what oil you running in it?

hi nrgserv
Yes i have changed the filter and was running castrol 15w-40, so i changed it again after 300km and put in 20w-60 to see if it made any difference but alas no change
regards
bill

sounding like a worn pump. if it were all the time would've said pressure releif valve / spring, but as its not bad with cold thick oil, kinda rules it out.
cant really advise any further as i've not had a 300tdi oil pump out before.