Please help with weird oil pressure problem
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Teching In
Joined: Jan 2023
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Please help with weird oil pressure problem Hi all I’m a new member here and new to the LS engine family. Just purchased a 200,000 mile 2009Pontiac G8 GT 6.0 L 76 engine car. Quick backstory. Derek oil change 5W 30 from about 40,000 miles highway driven every day. I purchased the car only needing a few minor suspension components. I noticed one day after letting it run idling at about 550 rpm hot it started to have an upper and tick no definitely not a DOD Lifter and definitely not a exhaust leak. When I purchased the car it had a check engine light for low oil pressure after scanning the car with my scan tool as I am a mechanic but I do not do anything to do with high-performance engines I found the oil pressure center is working properly. After changing the oil in the car to 15 W 40 shell Rotella like a lot of people recommended the oil pressure at idle after running for over an hour was about 30 and engine is quiet as a mouse now fast forward a few days later and a few starts later it started to tech again went and grabbed my scan tool and engine oil pressure is at six psi. I have had so many people tell me the lifters are junk and or the bearings in the engine of junk. How could that be true there is no noises whatsoever when the oil pressure is high but for some reason it just decides to drop off sometimes and sometimes it can run for over an hour with good oil pressure wow I don’t understand it and everyone out there has a different opinion. I have decided to put a high-volume high-pressure milling oil pump in and I’m hoping that that will solve my problems. No one seems to have any good ideas on why the oil pressure is good one day and bad the next I’m hoping it is the relief valve in the oil pump that has failed. What do you all think
Hi all I’m a new member here and new to the LS engine family. Just purchased a 200,000 mile 2009Pontiac G8 GT 6.0 L 76 engine car. Quick backstory. Derek oil change 5W 30 from about 40,000 miles highway driven every day. I purchased the car only needing a few minor suspension components. I noticed one day after letting it run idling at about 550 rpm hot it started to have an upper and tick no definitely not a DOD Lifter and definitely not a exhaust leak. When I purchased the car it had a check engine light for low oil pressure after scanning the car with my scan tool as I am a mechanic but I do not do anything to do with high-performance engines I found the oil pressure center is working properly. After changing the oil in the car to 15 W 40 shell Rotella like a lot of people recommended the oil pressure at idle after running for over an hour was about 30 and engine is quiet as a mouse now fast forward a few days later and a few starts later it started to tech again went and grabbed my scan tool and engine oil pressure is at six psi. I have had so many people tell me the lifters are junk and or the bearings in the engine of junk. How could that be true there is no noises whatsoever when the oil pressure is high but for some reason it just decides to drop off sometimes and sometimes it can run for over an hour with good oil pressure wow I don’t understand it and everyone out there has a different opinion. I have decided to put a high-volume high-pressure milling oil pump in and I’m hoping that that will solve my problems. No one seems to have any good ideas on why the oil pressure is good one day and bad the next I’m hoping it is the relief valve in the oil pump that has failed. What do you all think
Joined: Apr 2006
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From: Grand Rapids, Michigan
So okay, I recently purchased a Saab 9-7X with the exact same problem as you're describing. I'm in the middle of the engine tear down as we speak ( '06 LH6 5.3 ). What I can tell you is that so far, the only thing I've discovered is that the oil pump pick up o-ring was rock hard and split the second I attempted to remove it. I can't be 100% positive that this was the issue, but it's a known failure point. I cracked open the #2 rod cap just to have a look, and the bearing looked nearly new. The rod journal wasn't perfect, but it's nothing that I'm concerned about. Obviously I have a bunch more to do to finish tearing it down, which will likely be Monday unless I decide to mess with it after work, but I'll post up what I find ( if anything ). Might locate something that could help you.
Joined: Apr 2006
Posts: 3,911
Likes: 1,158
From: Grand Rapids, Michigan
I finished my teardown, the inside of the oil pump looked perfect, just like yours. Bearings all looked good, the cam bearings had a little wear - but the pistons and cylinder walls were destroyed. Biebs is likely on point, the DOD system is a typical culprit in these cases. Do a DOD delete and it will probably fix your issues. I'd still want to see what your oil pump pick up O-ring looks like, though.
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Teching In
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I finished my teardown, the inside of the oil pump looked perfect, just like yours. Bearings all looked good, the cam bearings had a little wear - but the pistons and cylinder walls were destroyed. Biebs is likely on point, the DOD system is a typical culprit in these cases. Do a DOD delete and it will probably fix your issues. I'd still want to see what your oil pump pick up O-ring looks like, though.
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Hi all I’m a new member here and new to the LS engine family. Just purchased a 200,000 mile 2009Pontiac G8 GT 6.0 L 76 engine car. Quick backstory. Derek oil change 5W 30 from about 40,000 miles highway driven every day. I purchased the car only needing a few minor suspension components. I noticed one day after letting it run idling at about 550 rpm hot it started to have an upper and tick no definitely not a DOD Lifter and definitely not a exhaust leak. When I purchased the car it had a check engine light for low oil pressure after scanning the car with my scan tool as I am a mechanic but I do not do anything to do with high-performance engines I found the oil pressure center is working properly. After changing the oil in the car to 15 W 40 shell Rotella like a lot of people recommended the oil pressure at idle after running for over an hour was about 30 and engine is quiet as a mouse now fast forward a few days later and a few starts later it started to tech again went and grabbed my scan tool and engine oil pressure is at six psi. I have had so many people tell me the lifters are junk and or the bearings in the engine of junk. How could that be true there is no noises whatsoever when the oil pressure is high but for some reason it just decides to drop off sometimes and sometimes it can run for over an hour with good oil pressure wow I don’t understand it and everyone out there has a different opinion. I have decided to put a high-volume high-pressure milling oil pump in and I’m hoping that that will solve my problems. No one seems to have any good ideas on why the oil pressure is good one day and bad the next I’m hoping it is the relief valve in the oil pump that has failed. What do you all think
You need to realize you are reading the oil pressure from a sender. Those can go bad. An accurate way to measure would be a mechanical test gauge plugged right into a port.
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Joined: May 2020
Posts: 252
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From: USA
I've even seen new lifters on top of a beat up cam.
The metal goes right to the cylinders for some reason.
I've had flat tappet big blocks years ago that have eaten several lobes off the cam and never a single scratch on the cylinder walls.
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Teching In
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yes I realize the senders can go bad I’ve had many trucks with the 5.3 in it and have changed out quite a few of them at the shop. My problem is it is reading accurate pressure because when the skin tool shows 5 pounds of pressure is when it starts ticking and when I give it gas the oil pressure rises and the ticking starts to go away so seeing it fluctuate with the scan tool tells me that it’s working. And all the ones that I have changed in the past have died completely and got stuck at a certain pressure.
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