Cold Oil Cooler

[RUYSENAARS]

I have a 1983 300d Turbo, and have a weird proble. I have posted on this forum before about it. When the engine is at normal operateing temp. and at idle the oil pressure is almost zero. When I take off from a stop the pressure immediatly goes up(up to 3bar). Long story short, replaced oil pump, rod/main bearings, (old ones did not appear worn!), but while I was there..... STILL no change. The car now has 190k and 20w-50 synthetic. I have put 30w in it, no change either. Really racking my brain!!! I have noticed that the oil cooler is cold, even after a long drive, by the way I live near houston, TX it gets HOT down here!! So I thought oil thermostat was bad, thought about replaceing, but thought again, and just took it out all together. STILL no change. ARRRRRRRRRGGGGGGGG!!!@!# ANY IDEAS!!!!!!
p.s. engine doesn't seem to burn too much oil, about a quart every 2k or so.