95 Discovery- Funny, I used to have Buick215's and now can't remember where the pressure relief valve is. Meanwhile - had the oil cooler line [upper] off to verify flow and direction and was not impressed by the volume, but it was there. Problem is the good oil light switch isn't getting enough pressure to turn it off and to quiet down the lifters.
Also changed the oil filter to check for flow.
Is it possible to have a stuck pressure relief valve robbing pressure and still allow some flow? This guy has been sitting for a year or more. Just got it- can't imagine the previous owner driving it with the oil lite on all the time.
Cheers

 

You should plan on doing an mechanical oil pressure test both cold and hot at both an idle and around 2000RPM's.
You may have a plugged up oil pick up tube, a failed oil pump aor other problems.
Mike

 

Hi and thanks,
Question- 1 - Is it possible that the relief valve is stuck in a spot that permits oil flow and bad pressure?
2 - Where is the relief valve?
3 - Is there a higher performance oil pump/kit available out there as there used to be for the Buick variant and still is for the Corvair[similar set up and gears as the Buick]
Thanks

 

About oil pressure tests - I am trying to find the right adapter for it now

 

1 Possibility
2Behind the front cover
3I am not sure but I don't believe there is a high performance kit, I have never heard of one.

May want to consider flushing the engine then pulling the oil pan and cleaning it out while inspecting the oil pick up tube.
Mike

 

Hi and thanks some more,
I'm still trying to make an adapter for the pressure test. All mine are for smaller German style cars.
It seems that they have changed the pump style and cover from the 3.5.
I wonder if I can remove the distributor and spin the pump directly as on some other V-motors?
Is there a diagram on the oiling system on the web?
Thanks again

 

I am drawing a blank on that, sorry.
Mike

 

Hi all,
I drained the oil and made a mix of oil and diesel fuel to flush- in the first 30 second test the oil light went off for one second around the five second point. The next flush test the light went off for 3 or 4 seconds around the same time. Never went off again.
I made an adaptor for testing the oil pressue- 3 to 4 lbs, clearly not enough to turn off the light.
Up onto the lift. Pulled the pan. Easier than I thought. Dropped the pick up tube. Very clear and unclogged, altho the pan was filled with crud AND lots of bits of red silicone gasket maker from the previous amateur attemps by a local 'professional' shop.
Seems that none of this has gone through the system .....seems.
I pulled a main and a rod cap. Crank surprisingly smooth and all bearings worn to top of the copper. I wonder how much the pressure will increase when I put new ones in.??????
Next step, I shall introduce a steady controlled 30 lbs of air pressure through the oil light hole to see if I can tell if there is any noticeable and obvious location losing pressure. This with a stethascope, or take an oil bath.
Well, that's it for now.
Comments please.

 

You may have a tired oil pump. The other tning to look at would be the pressure relief valve under the fron cover, had a friend with a similar problem, he adjusted it and brought his pressure up.
Mike