87 Gn low oil psi


I bought a pretty rough 87 Gn with engine problems.

I finally pulled it up to the garage to figure out what was going on with it.
Low oil psi light on. Lifters rattling,
Pulled the oil filter and. Nothing come out.
Pulled the turbo feed line off started the engine and nothing came out.
Decided to pull the engine sent it to the machine shop. They tore it down and called me to tell me there nothing wrong with the engine.
He asked if I was sure it didn't have oil psi. Yes I'm sure. Not one bearing is torn up. Any help would be appreciated.


Resident mad scientist
Staff member
these engines seem like they will lose prime to the oil pump once in a great while, when they get old. I have seen it once or twice over the last 25 years (not my own car, but friends and such).

so, now that its apart, what to do.......?


Nick Micale

Tech Advisor
Staff member
Seems like the wrong path was taken as you do not take a Buick V-6 engine apart first to diagnose a no oil pressure issue?

The main culprit is the oil pump, and that is in the front timing cover. Only a few times over many years I only have experienced a couple turbo engines that suddenly lost oil pressure.

One was the oil pump separated from the gear, no noise, no pressure, ran OK.

A couple times a cam bearing moved out of place, and no pressure.

Not seen it personally, but do know of a couple instances the oil pick screen was plugged up with trash.

My opinion, I would have tracked down the issue before the engine was removed and torn down.

Good luck with this issue, and please post what you find out.


Well-Known Member
I had a NA 3.8 Buick that lost oil pressure. It was a piece of the plastic timing chain gear that got stuck in the oil pump relief valve. Held it open, easy fix.

Oh yea, it also barely made any power as the lifters clattered like crazy (collapsed).


Gene Van Horn

Active Member
Could just needed to be reprimed. Packed with vasoline and started, agree100percent with Nick, never unseal the engine without first diagnosing a real problem. Now if your like most of us you have to think total rebiuld, more hp,better parts,bigger turbo,better suspention,stronger tranny, its,an endless cycle. 10,000,15,000.20,000 its endless. I got 40,000 in a car aint worth 20,000 as many will attest to hear. Good luck and have fun.


runs with scissors
Find my oil pump article and you can see how to set the pump up for better oiling.

...even though that advice isn't the fix for you now.

If you're not 100% CERTAIN the shop kept the tappets in the right hole DO NOT reuse that cam or lifters. I'd recommend going roller cam. Yes it's more money, but it's cheaper than two rebuilds and a roller cam.