Hi all:

I had the low oil pressure scenario on my '86 Sport and replaced the o-ring under the front cover which did absolutely nothing for the low pressure problem. To make sure I'm being clear, the low oil pressure scenario I'm describing is that I get normal oil pressure at startup, which drops to 30 psi at freeway speeds and zero or close to it at idle once the engine is warm. Mazdatrix' description of the o-ring "push-out" behavior in the 86-88 motors sure sounded like an accurate description of my problem, and in doing the replacement, I used Hylomar to keep the o-rin in place and deleted the front cover gasket. I did use a gasket on the oil pan and was pretty careful with my sealant bead.

So now I've still got the same oil pressure profile. And to top it off, I've also now got a pretty significant oil leak that only seems to happen after engine shutdown.

Any experience with similar situations, ideas or direction before I start banging myself in the head with a ball peen hammer?

 

I had two leaks on my 88 gxl. First problem was the oil coller and lines the oil coller lines are know to cause leaks. Next was my front cover seal and gasket and oil pan. Also what oil are you running? Makes a diff i usally run 20-50 in the summer and 10-40 in the winter.

 

Also might want to check those 4 little oil lines they are plastic and probably pretty easy to crack.

 

I don't believe in mystery leaks. Degrease/wash the engine and find out where it is coming from. Any sealing point or oil carrying hose can leak. Since you didn't mention a leak prior to your 'repair', thats a good place to start. But, all the oil cooler and oil injection lines are pretty old.

And, being a 20 year oil car, sometimes oil pumps wear out. I recently worked on a low oil pressure vehicle and found a hung open, because of varnish, oil PSI dump. Valves that control pressure might hang or break the return spring. The situation is rare but it happens.