Yes, I know this has been covered. I've searched and read many posts on this, but I'd like to run it by you all just the same.
Video of the problem.
https://youtu.be/1aVhZSdAuQ8
On cold start, no oil pressure for about 6 sec or so. After that, pressure reaches 4 or 4.5 bar. I hear a groaning noise up front. If I let the car idle for about 3 or 4 minutes, shut it off, then back on again, the pressure goes up to 5 bar and the noise goes away. If I do not restart the car, the noise continues. If I restart the car too early, before it warms up, the pressure goes to 4 or 4.5 bar and the noise continues. Once it hits 5 bar after a restart, the noise does not return until the next cold start.
Things I've tried with no change:
-changed oil and new Mahle filter.
-poured oil down filter mount hole.
-tightened crank bolt
-pulled OPRV and replaced the o-rings, piston moves freely
-replaced OPRV with another, but I don't know if it is good or not. Very slight binding at the bottom when pushing in the piston.
-changed oil to 10W-40. I've used this for the last 20 years. I switched to 20W-50 about 6 months ago.
One thing I haven't tried is starting the car with the OPRV out and see if oil gushes out or not. Haven't looked at the nuclear options yet, oil pick up tube or oil pump, although I would think those would give low pressure all the time.
Watchall think?