no oil pressure on cold start!?

[xero]

Hi guys, so I recently replaced my head gasket as it was leaking a bit and there was a little milky stuff in both the oil and water, so I changed the gasket a few weeks ago and it's been running great but now suddenly when I start the car in the morning or after sitting a few hours I have no oil pressure, if I let it wasm up about 30 seconds and then give it A slight rev the pressure will go up to 5 bar and stay there, till the ening warms up completly and then it will drop to about 3 bar at idle and 4.5 bar when I'm driving which is fine, but jst the cold start pressure thing is scarry....the lifters make a little noise when the guage is reading 0 and then quiet down when it goes to 5 but when it's at 0 it's just a little noise not all loud as if it actually had no pressure so I'm thinking maybe it's like 0.5 bar or something? any suggestions? btw I tried putting on a new oil filter with no luck and my car is a 1986 944 turbo

[rb101]

Same brand oil filter? If so switch to a purlator or mahle. Did you take the crank pulley loose during the head gasket replacement and retorque to 150lbs? Only thing else would be a sticking oil pressure valve.

[Tapage]

also maybe check your oil press sender unit ..