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Preface: 06 Sierra, lq9, 165k
Currently showing 40psi at cold start and stays there until coolant reaches operating temp. Hot idle will usually sit around 32psi some times dip down to 25psi. Will not go over 65psi at WOT. It used to never be lower than 40psi at idle and would peg out to 80psi at WOT. I changed the oil pressure sending unit hoping that was it, no change. I have not hooked up a mechanical gauge to check it.
Looking for some thoughts.
Is my gauge cluster just malfunctioning? Oil pump? Pickup tube o-ring? Engine trash? Let me know what you think.
I read once upon a time something about gm saying that the engine is only supposed to produce 10psi for every 1000 rpm. I don’t buy that.
By Jon Goyette
Here's an issue that has me stumped. 2000 Silverado, 4.3, 200K mi. Truck runs great, no oil consumption. I have a very random oil pressure fluctuation, normally I have 40 psi (+ or - 5psi) pretty steady, not affected by rpm or temp. about 20,000 mi. ago I started getting a lifter tick on start up accompanied by crazy fluctuation in oil pressure relative to rpm ( 15psi at idle and 60+ at 3500) It will do this for maybe a week and then stop....no tick and steady oil pressure again. Truck has always had regular oil changes with quality oil (dino) and a Wix filter, I've tried Lucas oil additive, Marvel, different viscosities between 10-30 and 15-40 nothing makes it worse or better. Seems to go away by itself and then return completely at random. Sometimes it will go 5k with no issues, other times maybe 2k. Not affected by oil changes or mileage...just comes and goes. Always lifter tick and oil fluctuation....tick goes away and so does crazy oil pressure. WTF is going on?
I have just over 1,000 miles on the 2019 Trail Boss 4.3L motor. This morning for the first time I noticed the oil pressure gauge dropped to 30 when pulling into a parking spot and then sitting idle. When I revved the engine a little bit the pressure went back up to about 50-60. I have never seen it at 30, mostly stays like 40-60 range. Any cause for concern? As a reference I drove about 10 miles, mostly highway, and it is 60-64 degrees outside.
What do you all get for pressure readings with your motors - maybe list idle pressure and cruising pressure with the motor type.
Just an observation this evening. Have a 2017 Suburban, 3500 miles (purchased Jan, 2018). Temp outside this evening after work was -18*. Running original Synthetic 0w20 I believe, has not been changed yet (changing oil soon). Hit the start button and up and running. Oil pressure rolled up to 40, then a few seconds later rolled up to 60. It stayed at 60 for 10-15 seconds then ticked down to 50, stopped there for a second then down to 40. When its “warm” it’s normally at 40 (+/- 3), so anywhere from 37-43ish.
Was just curious if this was normal? First time starting in that cold of weather, have never seen it do that before. I’m sure others have been in much worse so looking for other experiences.
I have a diesel truck that simply starts at a higher pressure when it’s cold then slowly moves down. Have never seen a gasser move like this, and fairly quick between the movements. It wasn’t a slow increase or decrease. High temp for tomorrow is -16 so will be closer to -20+ when started tomorrow night. Will watch it again.
Approximately 2 years ago while driving my CEL came on. The code reader indicated low oil pressure and the oil pressure gauge was around 17-20 at idle. I changed the oil and filter and the pressure returned to normal (oil change #1). On that oil change I did two filter only changes. When due according to the oil life indicator I changed oil and new filter (oil change #2).
That oil and filter was changed according to oil life indicator (oil change #3)
Today while driving, once the truck warmed up, (15% on oil life monitor) the oil pressure dropped to 0 suddenly and shut engine off light came on. I pulled over shut the truck off and waited, checked oil (plenty of it), and started the truck back up. Oil pressure came back to normal and then dropped back to 0. I was close to home (<1 mile) and was able to limp home with start-stopping multiple times to maintain oil pressure. I changed oil and filter (oil change #4) and oil pressure returned to normal.
Can anybody comment on what is happening? I would like to avoid running into an oil pressure issue on a longer trip, if I am only addressing the symptom and not the cause. Could the cause really be the filter getting full, or the oil degrading despite the oil life indicator suggesting there is more life?
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