Low oil pressure

[WWW1975]

Hi all,

Here is where I'm at.

2003 Silverado 1500 hd with 6.0 l 275000 km , engine sounds good, no knocks

Low oil pressure 6 lbs confirmed with mechanical gauge right from where oil pressure sensor is located

Changed oil ring on pick up tube, dropped pan, cleaned pick up tube, changed oil pump, new oil pressure sensor.

STILL low oil pressure!!!

Please help. I'm out of ideas....

[sporty061200r]

Oil pressure is determined by pump and bearing clearance you engine is most likey shot cam bearings and main bearings shot Could easily lead to little to no oil pressuee

 

 

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[WWW1975]

Ok. Then why would I hear knocking? It seems to sound fine?

[WWW1975]

I meant to say why wouldn't I hear a knock? It sounds fine.

[txab]

Oil pressure is determined by pump and bearing clearance you engine is most likey shot cam bearings and main bearings shot Could easily lead to little to no oil pressuee

 

 

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^^^^ This. You probably have just enough oil supply to keep an oil film between moving parts for now

[Supreme Pizza]

Did you try changing the oil filter brand? Try changing to a heavier oil, possibly a different brand oil. If the motor has major internal problems, you will find out soon enough.

[WWW1975]

Some more info

Tested this morning with manual pressure gauge

Startup engine cold 15 psi

Warming up idling pressure slowly drops to 6.5 psi

Rev to 1000rpm- 12 psi

1500 rpm/ 15psi

2000 rpm/ 20.5 psi

2500 rpm/ 25 psi

3000 rpm 32 psi

Back to idle 6 psi

 

So the only time there's low pressure is idling after warmed up or foot on Brake when in drive

Thoughts?

[Supreme Pizza]

The oil pressure system is not real complicated. If your motor is worn out, its worn out. Try a different filter and a heavier oil. Not much else you can do. Drive it till it dies. If/when the motor throws a rod, put a used $150 engine in there from Pick'N'pull and cruise on.

[Supreme Pizza]

You might be able to install an electric pump to boost the pressure, but to what end? More oil pressure is not going to help if the cause of low pressure is a worn out engine.

[sdeeter19555]

Did you swap in a high volume pump? That might buy you some more time, but it sounds like it's tired.

 

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[muddkatt]

You can run thicker oils such as Mobil 1 20-50 and start saving money to do an engine swap. With those pressures, the bearings are worn and the only way to correct is either installing a high volume pump like sdeeter19555 mentioned, or rebuilding the engine.

[swathdiver]

If the pick up tube o-ring is the wrong one, installed wrong or something being wrong with it, it will also cause low oil pressure. What oil pump did you replace it with? Often times, new items can be faulty too.

[sefiroxx]

Versions of these engines had a screen inside the tube the oil filter screws into - a safety measure to ensure a failed/blown filter wouldn't spew junk into the engines.

 

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[Supreme Pizza]

In my part of the world, you can buy a used motor from PickNpull for super cheap. Comes with a 30 day - or for a couple bucks more you get a 13 month warranty. You should be able to get a local Craigslist mechanic to install it for $350-$500. Total cost should be between $750-$1000 including new plugs, sensors, fluids etc. Just make sure the motor comes from a vehicle that was obviously in an accident, and run a compression test on it before you pick that particular motor.

 

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