I've searched everywhere and I'm not finding anything.
Check out this video: https://goo.gl/photos/6wDkWDSqGRh4qBxh8

Just replaced my front cover because the oil pump failed.
Started it up and all was good until it got to warm idle (Coolant about 160), then the oil light came on. I'd never seen it before other than at startup. When I revved the engine to 1000RPM, the light went away.
Replaced Mahle OC261 filter with a Bosch one. Same issues. I'm running Rotella 15-40.
Bought a mechanical gauge to see what was going on and now I'm even more confused. Everything is fine until it gets hot. Then oil pressure drops to zero and then bounces around between zero and 35 at idle.

Cold Idle: 45psi
Cold 2000 RPM: 50psi

Hot idle: 35psi (anywhere from 35psi to 0psi)
Hot 2000 RPM: 40psi

What could be causing this? I'm planning to get the tall mobil1 filter and maybe thicker oil but I don't want to just mask another issue. I know it could be bearings, but I don't understand how the pressure could drop so quickly if it's bearing related.


I thought it might be the oil pickup or screen so I dropped the pan and it all looks good. Oil and pan were clean without and flakes or sludge.


Basically, losing oil pressure at idle when hot. But good pressure any other time.

 

I'd check the pump, new or not. Better safe than sorry considering the cost of a new set of gaskets vs the cost of a new front cover.

 

I had the same problem, using the same oil. A huge filter masked the problem. I don't understand why it would go from 0 to 35 though. That's nuts.

My problem was a scored front cover.

When the oil gets hot, it gets thinner and just presses out past the oil gear or bearings at a quicker rate. But yours is really odd and makes me wonder if you won't have a walked bearing somewhere. Are there any odd noises? A walked bearing was suggested to me by Abran but I was lucky enough that it was not the case . you can see the cam bearing with a good flashlight and careful moving around while the oil pan is off.

The the oil pump, even if new, would be the first suspect.

Wait wait wait. I just had another thought after reading another thread. Your return oil passages could be blocked. If that happened, oil might not return to the pan quick enough, causing the pump to gulp air. You could test that by driving it to temperature then stopping and checking the dipstick. See if the oil gradually goes up.

 

It's not making any abnormal noises. I'll take another look and see if I can notice anything with the cam bearing. Everything I could see last time looked good.
Thinking oil pump too. I just find it hard to believe after replacing the whole front cover. I opted for a new one just so I wouldn't have to worry about this stuff.
Anybody know if a new front cover from British Parts of Utah would actually be a reconditioned one?
I didn't pull the oil pump cover and check it out before I installed it. Just filled it up with assembly grease. I didn't want to mess anything up. But I guess I should have been more critical.

 

I amended my post while you were typing. See the last paragraph.

 

I doubt bputah would sell a reocnditoned one for new. I think a scored front cover is trash... And proved it by throwing mine in the trash.

As far as I know, a reconditioned front cover is cleaned trash with a new oil pump in it. I contacted several ebay sellers of reconditioned ones to ask whether they checked the oil pump housing and none responded. I'm pretty sure it is because they didn't check them.

 

Cool. I saw that thread too. I'll check it out. But I can get the pressure up with the rpms, so I'm thinking there's oil there. Will definitely check before I tear into it again. Thanks!

 

It's worth a shot . I hate taking everything apart too.

 

Thinking hydraulically, the symptoms you're describing could be attributed to debris or faulty spring pressure in the oil pressure relief valve. Which is integral with the front cover. Either that or leaking past the oil feed galley mate between the block and front cover. If this were my situation I'd be in contact with BP Utah and sort out a replacement through them. Worn bearings, yes, will cause low oil pressure but the low pressure would be constant, fluctuations or fluttering you have verified with a mechanical guage really can only be symptoms of a faulty relief valve or a crack in one of the pump gears. Both of which they just sold you.

 

Yeah, I was reading some old threads and got scared that I had walked a cam bearing based on others experience. But looking up through the cranks, it looks like the bearings are all in the right place.
My next step it taking the front cover off again. Either tonight or tomorrow.
Is there any way I can check the relief valve? I really don't want to try to work out a replacement if I'm not absolutely positive that the front cover is the problem.