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By Jason Morgan
Hello, I'm new to this forum. I have a 2012 GMC Sierra with 150,000 miles. The 5.3 litre engine has had the oil changed every time the oil life has hit 30% , around 5 to 6 thousand miles. The oil pressure dropped and I replaced the oil pressure sending unit (opsu) and the problem was fixed for about a month. The old screen filter under the opsu was dirty but not severely clogged. After about a month the oil pressure dropped to 20 lbs and the check engine light came back on. I am considering pulling the opsu back out , @ operating temperature, and squirting brake cleaner or something down the oil passage followed by 2 hot oil changes. My question is , 1: is this a good idea?, 2: where does that oil passage directly lead to?
By Aidan Grant
my 6.0 with 230xxx has low oil pressure but no knocks maybe a little tick though. When i bought the truck it had maybe 5-9psi cold dropping to 0 warm. Thought it may have been a pickup tube oring or oil pump so i went ahead and replaced the pickup tube, o ring, and pump. it now gets 20 cold 7 warm at idle and 0 warm at idle and 20 warm running 1700 rpm. Which is a lot better but still a problem. I am aware the bearings may be shot and need a total rebuild, that is not out of the options. It is not electrical or sensor based issue same psi with a mechanical gauge. However I need to replace my harmonic balancer and take off the timing cover again so i was looking at it and could it be as simple as a o camshaft retainer plate? it has a build in thin o ring which if fails will drain pressure as it connects the oil gallys. Am I correct in thinking that this could solve my issues? Any input is helpful, thanks.
By Brad OSullivan
New to the forum here, and I have a 2005 chevy silverado 1500 with the 5.3L. I drive to and from michigan from chicago for college every couple of weeks. The last time I drove up to michigan 2 hours into my drive the oil pressure gauge started slowly moving down from 40psi. Every 10 minutes it seemed it moved down a notch until it got to 15psi and then I pulled over just to investigate because the truck was running perfectly normal and no warning lights or anything were on. I did a walk around, no leaks, no engine noise and the oil level was in the same place as when I left. Also when I stopped the pressure gauge dropped to 0 at idle and the truck idled normal. I continued to drive till i got to my destinations 30 minutes later. The next day when I started it back up the oil pressure is now reading normal and has read normal for the last week. I went to tech school and I know my way around an engine and i'm almost positive this isn't a mechanical issue, im thinking its the oil pressure sensor or sending unit or it could be the gauge itself because first gen silverados are famous for bad gauges but i feel if it was a bad sensor there would be warning lights? Not sure though, any of you guys experience an issue like this or have any idea of what to check or what it could be?? Much appreciated!!
By Edward Kotchounian
i need some help i got a 5.3 i rebuilt. dropped into my tahoe and no start. well first i figured out im not getting spark.so my plugs are brand new and my ignition coils are fairly new. but i cannott get any resistance to come up testing coils but they worked fine a few weeks before ,i did have a bad random misfire and some knock but i advanced my timeing plus 2.any ways i noticed no oil pressure at all while cranking, so now im building a pressure pump to prime it with.this is my first rebuild im new to all this i bought a pc some engine books and a shit load of tools and im hooked. well please someone give me a hand with this its ****in up my life and marriage.if any one has some ideas call me or txt 8104934779. i really need the help. thank you johnny deere
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.
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