I have a 1993 Cabriolet Classic with a 1.8. Like many, it has oil pressure problems. Lots of pressure at startup (cold), but falling off fast as the engine warms up. I've used a mechanical guage to verify the pressure is down to only 5 lbs (or less) once heated up. At 2000 RPM, it barely makes the 29 PSI spec.

I've put a new, good filter in it, and replaced the oil pump, but the problem persists. I've checked the crankshaft and connecting rod bearings. They show some wear, but aren't what I'd consider "leakers." Same up top.

I noticed an enormous amount of oil blowing past the hydrolic lifters, but that doesn't seem inappropriate. Could there be a galley plug leaking or something? Is there anything else that might explain it, or is it likely, really just a bunch of worn bearings working in concert to annoy me?
Thanks for any advice you all can give.

 

What weight oil are you using. I did as many recommended and changed it to 20w50. This definitely helped with the pressure. Give it a shot and let me know.