Oil pressure drop after addition of OEM Oil Cooler?

OR VietVet · Sep 3, 2024

swathdiver said:
That's low and concerning to me given your setup. Put a new PF48 up there and drive it, then maybe change the lines out from Dorman to OE.

The best flowing, least restrictive, oil filters are the K&Ns with the 1" nut on the bottom. Nothing else comes close unless they (K&N) are lying.

Wix XP filters come close to the K&N and I have been using Wix for gobs of years with no problems. I did see a difference of oil pressure, only slight, with the PF filters.

DaveO9 · Sep 3, 2024

I have a wix xp on the way. We will see what happens. Thanks all for the comments and input!

Jetskier77 · Sep 3, 2024

I have not had good luck with anything from Dorman. Very cheaply made parts from overseas. That would be my first suspect part to look at.

swathdiver · Sep 3, 2024

Just Fishing · Sep 3, 2024

I get better oil pressure with the ACDelco filters, they seem to flow really well.
Or maybe it's just the inlet side design?
I like to run the same filter that my wife's 11 Buick enclave calls for (3.6 w/vvt).
Larger capacity, and it has more filter because of that, it gave me a few extra psi at idle.
Plus sharing the same filter is easier on me when I buy in bulk. :peace:

Years ago I had issues with the K&N with the nut on the end, I ran those in my vette but suddenly I couldn't get them to stop leaking at the base gasket.
I switched to a wix and haven't had any issues since.

This was probably 2020, and everything went to shit.
Or I was buying knock offs on amazon? Idnk.
I swore them off afterwards.

Meathead16 · Sep 4, 2024

Accidental double post from previewing post?

Meathead16 · Sep 4, 2024

In regards to the oil flow through the engine:

Engine lubrication is supplied by a gerotor type oil pump assembly. The oil pump is mounted on the front of the engine block and driven directly by the crankshaft sprocket. The pump gears rotate and draw oil from the oil pan sump through a pick-up screen and pipe. The oil is pressurized as it passes through the pump and is sent through the engine block lower oil gallery. Contained within the oil pump assembly is a pressure relief valve that maintains oil pressure within a specified range.

Pressurized oil is directed through the engine block lower oil gallery to the full flow oil filter where harmful contaminants are removed. A bypass valve is incorporated into the oil filter, which permits oil flow in the event the filter becomes restricted. A second valve, the active fuel management oil pressure relief valve is incorporated into the oil pan. The active fuel management oil pressure relief valve limits oil pressure directed to the upper oil galleries and valve lifter oil manifold assembly to 379-517 kPa (55-75 psi) maximum. When main oil pressure exceeds 379 kPa (55 psi), the oil pressure relief valve exhausts excess oil to the sump.

Oil is then directed from the filter to the upper main oil galleries and the valve lifter oil manifold assembly. Oil from the left upper oil gallery is directed to the crankshaft and camshaft bearings. Oil that has entered both the upper main oil galleries also pressurizes the valve lifter assemblies and is then pumped through the pushrods to lubricate the valve rocker arms and valve stems. Oil returning to the pan is directed by the crankshaft oil deflector. The oil pressure sensor is located at the top rear of the engine.

An oil passage at camshaft bearing location 2 permits oil flow into the center of the camshaft. Oil enters the camshaft exiting at the front and into the camshaft position (CMP) actuator solenoid valve. The CMP valve spool position is controlled by the engine control module (ECM) and CMP magnet. When commanded by the ECM, the CMP magnet repositions the CMP actuator solenoid valve spool directing pressurized oil into the CMP actuator to control valve timing. Refer to Camshaft Position Actuator and Solenoid Valve Description Description and Operation.

With active fuel management activated, the ECM commands the 4 solenoids to open, directing oil through the engine block oil galleries to the intake and exhaust valve lifters for cylinders 1, 4, 6, and 7.

How an oil cooler is incorporated into this circuit is not mentioned. However, it is mentioned for pre-07 engines. Considering how many design characteristics were carried over between the two generations, I feel it's safe to assume this is one of them. From a 2006 5.3 LM7:

An external oil cooler is available on certain applications, all 6.0L. (This calls out just 6.0L engines but this description is included for 5.3L) Oil is directed from the oil pump, through the lower main oil gallery to the full flow oil filter. Oil is then directed through the oil pan outlet oil gallery, located in the left rear of the oil pan, and to the external oil cooler via a hose assembly. Oil flows through the oil cooler and returns to the engine at the oil pan inlet oil gallery, located in the left rear of the oil pan. Oil is then directed to the upper main oil galleries and the remainder of the engine assembly.

Just Fishing · Sep 5, 2024

One thing I remembered from my old engine.
if you have AFM, my old 5.3 had some very loose valley cover bolts.
Like finger tight looseness.
That could contribute to lower oil pressure if the seals are leaking because of it.
Seems to be a somewhat common issue seen by many.

DaveO9 · Sep 5, 2024

Meathead16 said:
In regards to the oil flow through the engine:

View attachment 437034

How an oil cooler is incorporated into this circuit is not mentioned. However, it is mentioned for pre-07 engines. Considering how many design characteristics were carried over between the two generations, I feel it's safe to assume this is one of them. From a 2006 5.3 LM7:

View attachment 437035

Thanks much! Answers my question. Looks like all oil goes through the filter and then the external cooler after it's trip through the lower gallery. So can definitely see how the cooler and lines could affect pressure at the sensor.

I changed the filter today to the Wix XP. In the process, I have about a 1/2 quart less since I didn't replace the oil that was in the PF63. If either changed observed pressure, it's not more than 1-2 psi. A slight clarification from my earlier posts: I think I'm seeing slightly higher than 30 psi at 2k rpm now, whereas before the cooler add, I was seeing slightly less than 40 psi at same RPM. So it's probably not a full 10 psi difference, more like 6-8. I'm just using the dash gauge while driving, so not super accurate.

There has been some mention of replacing the dorman lines with GM. Something I will think about, but a lot of work with motor mount and front diff in. (Has anyone had success in replacing the lines without removing either?) I think before I do that I will reinstall the block off plate and see where I'm at without the oil cooler at all. Just to make sure I'm where I was before I added it. I do believe the cooler itself would have much more effect on the pressure drop than the lines would, regardless on the brand.

Just Fishing said:
One thing I remembered from my old engine.
if you have AFM, my old 5.3 had some very loose valley cover bolts.
Like finger tight looseness.
That could contribute to lower oil pressure if the seals are leaking because of it.
Seems to be a somewhat common issue seen by many.

Thanks, good to know. How much stuff you have to remove to get to those bolts? TB and intake manifold?

strutaeng · Sep 6, 2024

DaveO9 said:
How much stuff you have to remove to get to those bolts? TB and intake manifold?

Yes. It's not that difficult. I think those bolts loosen up on engines over like 200k.

Mine were a little loose as well at around 245k. I can't remember if I added Loctite when I rebuilt the engine. Probably a good idea at add a tiny drop of the blue Loctite?

Oil pressure drop after addition of OEM Oil Cooler?

OR VietVet

Multnomah Falls

DaveO9

Full Access Member

Jetskier77

TYF Newbie

swathdiver

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Just Fishing

Can't fix stupid

Meathead16

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Meathead16

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Just Fishing

Can't fix stupid

DaveO9

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strutaeng

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