The V8 Owners Forum -

Just noticed my V8 has decided to have no oil pressure...

No apparent reason. Had it 2 days ago.

So could this be a stuck pressure release valve?

Can I get at that without taking the lump out or taking too much off the motor? I have good access to the front.

This is what I have:

some more pics

So I dropped the oil, (black and smelly) and took off the oil pump cover.

The surface doesn't look good.

I don't know if the relief valve piston is in the right place?

And another pic

rich112 wrote: ↑Sat Jul 10, 2021 5:56 pm So I dropped the oil, (black and smelly) and took off the oil pump cover.

The surface doesn't look good.

I don't know if the relief valve piston is in the right place?

20210710_182901 (Medium).jpg20210710_182908 (Medium).jpg20210710_183000 (Medium).jpg

Undo the big bolt on the left and pull out the spring and plunger, which should be moving freely.

Also verify whatever you are using as a gauge is working correctly. Wear and scoring would be typical and not a reason for "no" oil pressure.

The wearing and scoring marks are normal.

But, do you get oil pressure if you rev it up?

Chris.

ChrisJC wrote: ↑Sat Jul 10, 2021 8:14 pm The wearing and scoring marks are normal.

But, do you get oil pressure if you rev it up?

Chris.

No sign of oil pressure. I didn't want to rev the motor past 2k.

The gauge was working fine.

The motor sounds noisy so defo lacking pressure.

I'll check the valve for free movement.

I can easily clean up the cover plate and put in some uprated pump gears and then see how it runs.

I might pop the sump off to check for metal in the pan.

Do you have oil? Was there a catastrophic leak? Sump plug come out?

Ian

Make sure you pack the pump with Vaseline when you re-assemble or you’ll struggle to prime it

Ian Anderson wrote: ↑Sat Jul 10, 2021 8:28 pm Do you have oil? Was there a catastrophic leak? Sump plug come out?

Ian

No loss of oil at all.

I drained 4-5 litres out of the sump.

rich112 wrote: ↑Sat Jul 10, 2021 9:19 pm

Ian Anderson wrote: ↑Sat Jul 10, 2021 8:28 pm Do you have oil? Was there a catastrophic leak? Sump plug come out?

Ian

No loss of oil at all.

I drained 4-5 litres out of the sump.

Was the low oil pressure light on as well as the gauge reading low?

DaveEFI wrote: ↑Sat Jul 10, 2021 10:32 pm

rich112 wrote: ↑Sat Jul 10, 2021 9:19 pm

Ian Anderson wrote: ↑Sat Jul 10, 2021 8:28 pm Do you have oil? Was there a catastrophic leak? Sump plug come out?

Ian

No loss of oil at all.

I drained 4-5 litres out of the sump.

Was the low oil pressure light on as well as the gauge reading low?

Yep. Sadly, I think it's probably spun a bearing. I'll take the sump off and see if I can check for metal and a lose big end... The pressure loss was not gradual.

Check oil pick up bolts are tight and gasket intact or it will suck air.

Ian

Ian Anderson wrote: ↑Sun Jul 11, 2021 6:45 am Check oil pick up bolts are tight and gasket intact or it will suck air.

Ian

Just what I was about to post as it happened to me. However, I didn't lose all pressure immediately, that would probably need the oil pick up to fall off into the sump.

I'd have thought if a bearing had failed enough to drop the oil pressure to zero, you'd hear it knocking?