6.0L Low Oil Pressure Issue

Matthew Walz · February 19, 2021

As this issue comes up a lot, I can't seem to find my specific situation.

My 2009 chevy 3500hd with the 6.0 had low oil pressure. Around 35 or so I figured it was the pump. Did that and the o ring and nothing. (Did it once before on another 6.0)

My mechanic replaced cam phaser, timing chain(had other issues), oil pump, some other stuff in that region, new valve springs, new heads and new lifters.

Engine was also generating a lot of heat although wasn't overheating. Replace the oil pressure sensor behind the intake too. Was within spec while driving (20psi) or idle (6 or 7psi I think), but now the oil pressure light is going off and dinging. Engine runs perfect, idles perfect, with no lifter noise.

Is it possible its the cam bearings? We are running 10w 40 oil and Lucas to thicken it up but still has no effect.

Want some opinions before diving in further.

CamGTP · February 19, 2021

Can you verify the pressure with the mechanical gauge?

Sharpz · February 19, 2021

It does sound like warn bearings. If your 6.0 is a high mileage motor, it is likely the culprit. I am pretty sure your truck has a filter under the oil pressure sensor too. I didnt see where you said you changed that. You might want to replace it if you havent.

Dustoff87 · February 19, 2021

On my 5.3 there is a small filter element under the oil sending unit. If you're not getting any knocking noises which indicate actual low oil pressure that filter element might be clogged. That's what my problem was. $7 fix for my issue.

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Matthew Walz · March 18, 2021

Update, sorry its been a while. there was no screen in the 6.0 engines, we did install a new sensor which seemed to help. After running 2 quarts of lucas stabilizer and 10 30 oil, pressure does not ding when it gets low as often. Taking it to a more experienced mechanic today and if the mechanical gauge reads good then we will check out the gauges, the rpm gauge has been messing up. If it shows low pressure, I'm taking it to a dealer and trading it in. Not worth putting more money in to and I don't have the money for an engine.