low oil PSI when passing

[slyhog022056]

2010 GMC Yukon XL, 5.3...... Yesterday I made a round trip from Dallas to Memphis, 4 times along the way while accelerating to pass someone my oil pressure dropped from the normal 20 PSI to the point the oil light came on and I had to pull over and shut it down. Was only 1/2 qt low on oil. Today (the next day) I have about 18 PSI at idle and about 25 PSI at 2,000 rpm.
Just about a month ago I had to pull intake to free up a stuck lifter and also replaced the oil sending unit and screen and also did a full oil change because I had no oil pressure on start up. The oil filter was only 4 months old and was totally collapsed internally.
I have never had over 30 PSI of oil pressure, ever. Truck only has 210,000 miles on it.

I have read a few posts on here and someone mentioned a port at the front of the engine right after the oil pump that I can put a manual gauge into. Where is the port? I can't find anything referencing it. And also someone mentioned a oil pump or pickup tube "O" ring problem????

 

[donjetman]

change you oil pump pickup tube o-ring

 

[donjetman]

Do you have some oil consumption going on? GM came up with TSB technical servive bulletin: new improved valve covers ot the 07-08 and 09-11 engines to lessen oil consumption. Read it here:
https://f01.justanswer.com/ebrock63...il+Consumption,+MIL+ON,+Engine+Runs+Rough.pdf

 

[j91z28d1]

I thought I had a pic of mine but it's the port in this video he uses for priming the oil system.

the port is the same size as the sensor port up top.
it's a 16mm crush washer type of fitting same as this one. some oil pressure test kits have the right one. some don't. just an example. I think you can find cheaper.

LS Swap Oil Gauge Adapter Fitting, 16MM x 1/8 NPT https://a.co/d/g0VpEX2

you could try the over fill trick or park downward on a big hill to see if that effects the oil pressure. that is said to be a test for that o ring.

what brand of filter did you have that failed?

 

[blackelky]

2010 GMC Yukon XL, 5.3...... Yesterday I made a round trip from Dallas to Memphis, 4 times along the way while accelerating to pass someone my oil pressure dropped from the normal 20 PSI to the point the oil light came on and I had to pull over and shut it down. Was only 1/2 qt low on oil. Today (the next day) I have about 18 PSI at idle and about 25 PSI at 2,000 rpm.
Just about a month ago I had to pull intake to free up a stuck lifter and also replaced the oil sending unit and screen and also did a full oil change because I had no oil pressure on start up. The oil filter was only 4 months old and was totally collapsed internally.
I have never had over 30 PSI of oil pressure, ever. Truck only has 210,000 miles on it.

I have read a few posts on here and someone mentioned a port at the front of the engine right after the oil pump that I can put a manual gauge into. Where is the port? I can't find anything referencing it. And also someone mentioned a oil pump or pickup tube "O" ring problem????

Only 210,000 miles?

 

[SNES Avalanche]

2010 GMC Yukon XL, 5.3...... Yesterday I made a round trip from Dallas to Memphis, 4 times along the way while accelerating to pass someone my oil pressure dropped from the normal 20 PSI to the point the oil light came on and I had to pull over and shut it down. Was only 1/2 qt low on oil. Today (the next day) I have about 18 PSI at idle and about 25 PSI at 2,000 rpm.
Just about a month ago I had to pull intake to free up a stuck lifter and also replaced the oil sending unit and screen and also did a full oil change because I had no oil pressure on start up. The oil filter was only 4 months old and was totally collapsed internally.
I have never had over 30 PSI of oil pressure, ever. Truck only has 210,000 miles on it.

I have read a few posts on here and someone mentioned a port at the front of the engine right after the oil pump that I can put a manual gauge into. Where is the port? I can't find anything referencing it. And also someone mentioned a oil pump or pickup tube "O" ring problem????

When our trucks came from the factory the oil pressure gauge sat 40 PSI at idle and would move up to 60 under acceleration.

You've already unstuck a lifter so more than likely your engine is on the way out.

You can replace your Oil Pickup tube O ring and even the oil pump but you're at the point of needing a full rebuild sooner or later

 

[Dustin Jackson]

Dropping oil pressure under acceleration goes against how oil pressure is supposed to work so this is a new one to me

If the problem started after you did all that work I would try to put the old oil pressure sensor back in and see if the new sensor is the cause. I wonder if the sensor is defective

 

[B-train]

The oil filter failure has me stumped......either its a cheap filter, or that pump is really pushing oil through, or the motor has a lot of carbon that is moving through and plugging it up.

2 areas of oil loss that I am aware of: oil pump pickup o-ring - very common, especially at 210k in the southern heat. Also, it has been mentioned about the VLOM on other threads. I don't have experience with that system on mine, but my guess is if the o-rings that seal those passages have gotten hard and flat, you could be losing pressure there as well.

I chased low oil pressure years back on my 6.2L 2007 Denali - it would have lifters ticking on hot restarts and low pressure. I did the oil pump o-ring which helped, but didn't solve it. I then pulled the intake and found all 8 o-rings on the valley cover were flat and hard - oil bypassing into the valley. Replaced for $40 and pressure back up to factory spec. Both repairs aren't too bad with mechanical knowledge. The oil pan is a PITA on your back, but can be done.

 

[avalonandl]

I would only use a Wix filter or AC Delco

 

[j91z28d1]

Dropping oil pressure under acceleration goes against how oil pressure is supposed to work so this is a new one to me

If the problem started after you did all that work I would try to put the old oil pressure sensor back in and see if the new sensor is the cause. I wonder if the sensor is defective

honestly you're probably right about the sensor.

I have heard of low oil pressure under load and high rpm in the performance world, it's almost always worn cam bearings in the ls engines. but those are more simple non afm/vvt engines. these seem to have all kinds of places oil could be bypassing.