Low Oil Pressure in my Daily Driver--Please Help!
04-15-2016, 06:47 PM
#21
If you check the pressure at the auxillary port in the block in the oil galley and it is low, then it could be the pump, clogged screen or bad o-ring.
Ive tried THICK oil in my 03 6.0 with 170k and it was marginally better. If you have a me hanical gauge giving you low pressure after the pump and before the filter, then the OEM sending unit is working.
Pressure is a measure of resistance in the system. If o ring is not sealing, the bypass in the pump is stuck open or the screen is clogged, you will see low pressure. Get a AC delco filter and factory rated oil to test. Crappy oil filters with poor anti-drainback valves in them can give you low pressure at startup.
My fix was a simple o ring replacement. It was simple on my 2wd truck. 4x4 will be more involved but I did the oring only by taking oil pan off.
Ive tried THICK oil in my 03 6.0 with 170k and it was marginally better. If you have a me hanical gauge giving you low pressure after the pump and before the filter, then the OEM sending unit is working.
Pressure is a measure of resistance in the system. If o ring is not sealing, the bypass in the pump is stuck open or the screen is clogged, you will see low pressure. Get a AC delco filter and factory rated oil to test. Crappy oil filters with poor anti-drainback valves in them can give you low pressure at startup.
My fix was a simple o ring replacement. It was simple on my 2wd truck. 4x4 will be more involved but I did the oring only by taking oil pan off.
04-15-2016, 07:11 PM
#23
It shouldn't give you any problems. It's a good size plug. Just make sure you have the 3/8" extension IN the plug so it does't get rounded out. If it makes you feel better, hit it with a propane torch on the block. There may be some factory locket/sealer on the plug.
The o ring seems to be a VERY common issue on these trucks when they get some mileage on them. IF you go as far as taking the front of the motor apart to inspect the pump, check if there is any debris holding the bypass valve open allowing the pressure to bleed off. I believe the OEM pump bleeds off at 50 or 60psi?? not 100% sure.
A high volume pump MAY bring the pressure up some but it would be a bandaid for a bigger problem IF you have a good o-ring, screen is not clogged, filter and pump are in good working order. Last on the list I would think would be bearing clearances...which you can't check until you tear down the motor.
Check/double check and do a lot of test before spending money. It would suck to tear the motor down only to find out it was an o-ring. I would look there first. It will cost you some time, a o-ring (red I believe is the updated version), oil pan gasket and oil change consumables.
Pickup tube 10mm bolt (I believe)
O-ring stuck in the pump
New red o-ring. You can see the old one got "flattened out"
The o ring seems to be a VERY common issue on these trucks when they get some mileage on them. IF you go as far as taking the front of the motor apart to inspect the pump, check if there is any debris holding the bypass valve open allowing the pressure to bleed off. I believe the OEM pump bleeds off at 50 or 60psi?? not 100% sure.
A high volume pump MAY bring the pressure up some but it would be a bandaid for a bigger problem IF you have a good o-ring, screen is not clogged, filter and pump are in good working order. Last on the list I would think would be bearing clearances...which you can't check until you tear down the motor.
Check/double check and do a lot of test before spending money. It would suck to tear the motor down only to find out it was an o-ring. I would look there first. It will cost you some time, a o-ring (red I believe is the updated version), oil pan gasket and oil change consumables.
Pickup tube 10mm bolt (I believe)
O-ring stuck in the pump
New red o-ring. You can see the old one got "flattened out"
Last edited by smitty2919; 04-15-2016 at 07:24 PM.
04-16-2016, 08:15 AM
#24
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Thank you for the quick replies and pictures smitty2919 and paul bell its worth a try and a chance to save some big $ in one of the diagrams the port plug looked like a hex must be a 3/8 square since you did this already thanks as soon as i get a chance i'll give it a try and let you know
Last edited by roofcleaner; 04-16-2016 at 05:50 PM.
01-03-2020, 09:14 PM
#27
Paul, I can't even see the side galley plug without removing some stuff...front diff in the way. So I removed the lines for the oil cooler and measured pressure there. Same as at the sending unit, about 16 PSI on startup, and trending toward 6 PSI at hot idle (600 RPM). I think this is functionally the same as the side galley plug, right?
This makes me think it is not a screen under the sending unit issue. Either the pump isn't making pressure, or there is not enough resistance to the pressure downstream, so pump volume is there but no pressure.
The barbell forces oil into the filter and the cooler, correct? And also seals the high pressure line from the back cover?
I had the transmission worked on last year. I had them replace the rear main while the transmission was out. Maybe they didn't replace the barbell correctly? But why no warning bell until a year later? Any way to tell if it's the barbell without dropping the transmission?
Other ideas that fit my symptoms?
thanks!
Paul
This makes me think it is not a screen under the sending unit issue. Either the pump isn't making pressure, or there is not enough resistance to the pressure downstream, so pump volume is there but no pressure.
The barbell forces oil into the filter and the cooler, correct? And also seals the high pressure line from the back cover?
I had the transmission worked on last year. I had them replace the rear main while the transmission was out. Maybe they didn't replace the barbell correctly? But why no warning bell until a year later? Any way to tell if it's the barbell without dropping the transmission?
Other ideas that fit my symptoms?
thanks!
Paul