6.2 Oil pressure

[Ratau]

Please help! What is the ideal engine oil pressure for the 6.2 diesel?

Thanks
Danie

[CleviteKid]

After the engine is warm:

about 50 psig at 2500 rpm,

about 20 psig at warm idle.

You did say ideal pressure. Many trucks have run many miles on less. Any more is just wasting energy shoving oil back into the pan past the pressure relief valve in the oil pump, but doesn't hurt the engine.


Dr. Lee :cool:

[britannic]

With the engine at operating temperature and dipstick oil level indicating full (tested when engine has stopped for at least 10 minutes), the mininum oil pressure readings are:

Idle 650-750rpm: 10psi
2000rpm: 40 psi

[Ratau]

Thanks for the replies. I couldn

[Ratau]

Now after I replaced heads and gaskets the oil pressure dropped. I changed the oil and filter after about 1000 km no change.

What could cause such a drop in pressure. Hot 3 to 4 psi at idle and 15 to 20 psi at 2000 rpm. It was 10 psi at idle and 40 psi at 2000 rpm.

How does the dump valve operate, could the dump valve be stuck open caused by the black sediment?

Could a low quality filter be the culprit?

If the bypass valve at the filter open will you lose pressure?

What path does the oil follow throughout the engine? :confused:

[SteveMc]

Ratau
You could have done something to the oil sending unit or wiring during the heads R/R. Use direct reading machanical gauge and see what you get. The sending units on GM engines are not known to be real reliable.

[Ratau]

The gauge in use is mechanical.

[SteveMc]

That oil pressure is way too low. If you are satisfied the manual gauge is correct, then next step is to check the rest of the engine. The strainer on the oil pump should take care of any junk that would mess up the relief (dump) valve, but you never know. If the oil pressure was ok before the heads replacement, then it sounds like something has made its way into the oil system. I would first check where the pressure gauge is attached to make sure the passage is not restricted. Also the line for the gauge. Things can get into the engine when the heads are off that could block up oil passages. Use lots of air to blow out the line and port, then crank without starting and see what the flow is like. That is all I can think of right now.

SteveMc

[5.7L oldsdiesel]

Could be the oil pump.I had one come into my shop yesterday to have a oil pan replaced,and i put everything back together perfectly and it had no oil pressure on start-up.I checked it with a mechanical gauge.But.......it had oil pressure when i put it in the shop for repair the day before.I removed the new oil pan and then took the oil pump down and found a broken pressure relief valve spring and the two gears inside the oil pump housing were rocking back and forth from side to side.How's that for a bad oil pump? smile.gif Changed the oil pump and oil pump driveshaft and all is well tonight.

[SteveMc]

There you go, it does happen. If Ratau finds that everything is ok with the line to the gauge, then the next step is to take the pan off and go inside.

But ols5.7, I got to ask you. Did your luck improve after that pump went south? What timing.!!! If the owner would have driven one more mile with the pump not working, you would have been doing more than changing the pan.

SteveMc

[5.7L oldsdiesel]

The engine runs much better now,and i agree,what timing indeed!The oil pump was in terrible shape.Especially the gears.The gears were actually scraping the housing inside the pump,and going from side to side.The engine had a bit of a rough idle before it came in.I was thinking afterwards that perhaps with the bad oil pump,the lifters were'nt getting their share of oil to keep the valves open,therefore affecting performance.Since the new pump is in,the engine runs much better.I was amazed at how the engine kept going with such a bad oil pump.I've never seen oil pumps go that bad. :eek:

[Ratau]

Could anyone tell me what the route off the oil is through the engine? Oil pump, filter, cooler and so on.

Here in South Africa we only get GUD and Fram Filters. What I understand from the GUD guy's that the Z24 filter don't have a pressure relive valve.

My question: if the filter can't do the job will the pressure go down or will the relive valve in the line open to bypass the filter? Could I use the filter intended for the Chevy 350 gas motor to do a test?

[Ratau]

Ok I took the pan off and the pump shows no wear at all. I also put a new pick-up on and checked the mechanical gauge with a new one. The two gauges reads the same. :mad:

Is the gauge pick-up after the filter and if so could it be that the filter cant handle the flow?

Any idea at what pressure the bypass valve at the filter will open?

I always used mono grade SAE 40 diesel oil but now changed to 15W40.

[Portland Suburban]

On a side note, my oil gauge reads 80PSI at 2500RPM+ and 40PSI at Idle. Is something wrong?

[Ratau]

Please pass some off that pressure to me.

It sound like the dump valve at the pump is stuck closed.