Oil pressure drop after addition of OEM Oil Cooler?

[j91z28d1]

Many specialized aftermarket pans made for road racing or drag racing have baffles located at different places (depending if you corner or are going straight with a lot of Gs) to help keep oil around the oil pickup tube in these situations. Kind of like how a fuel tank has a reservoir area around the basket or fuel pump sock to keep fuel in that area.

there used to be a company that made one for it, well a baffle for the stock pan. but they discontinued it. I had the pan off and was thinking of installing one. emailed them why it was out of stock everywhere. they basically said it didn't work.


shame.

that's weird about the listing. that just pops up when you google ls oil cooler bypass valve or something like that. I don't honestly know if it's correct or not. I did change hoses once because they all leak after a while which is probably what Dorman means by upgrade. maybe they learned how to use oil proof hoses and crimp them right so they don't leak after a few years like all the oem gm lines do?

 

[gooffeyguy]

@j91z28d1 that oil cooler bypass you linked earlier looks just like the oil filter bypass that's listed on RockAuto for my 2001 5.3l Yukon

A different part # though

 

[j91z28d1]

interesting. my 2011 yukon under shows the oil pressure relief valve for the afm stuff that screws inside the oil pan. shows the same type valve under the oil filter bypass valve and oil pressure relief valve. they look the same but different brands listed under each.

if I remember right there's not really a oil filter bypass valve. the dog bone forces oil down into the filter port from the oil pump. the afm relief doesn't really bypass the filter since it just vents to the pan, not into the engine passageways. the only really oil filter bypass valve is inside the filter itself. set at something like 12psi?

I don't remember, oil goes thru the filter before heading to the oil cooler right?

 

[OR VietVet]

interesting. my 2011 yukon under shows the oil pressure relief valve for the afm stuff that screws inside the oil pan. shows the same type valve under the oil filter bypass valve and oil pressure relief valve. they look the same but different brands listed under each.

if I remember right there's not really a oil filter bypass valve. the dog bone forces oil down into the filter port from the oil pump. the afm relief doesn't really bypass the filter since it just vents to the pan, not into the engine passageways. the only really oil filter bypass valve is inside the filter itself. set at something like 12psi?

I don't remember, oil goes thru the filter before heading to the oil cooler right?

IIRC, the oil starts in the pan, is pulled and pumped by the oil pump and then ran thru the filter, to parts unknown.

 

[DaveO9]

On my tahoe, it's sensitive to oil level.
If i fill it to the F line on the dip stick, i get lower oil pressure.

I read it's something about the oil being foamed up by the crank.

If i keep the level just under the middle between full and add, it's much better overall.

But it might just be something with the replacement dipstick or the 2019 dated block i have.

The MotorTrend show Engine Masters did an episode testing the amount of engine oil in the pan with an engine on the dyno. S3 E3 How Oil Kills Power.

Basically seeing the effects of more or less oil has on hp and oil pressure across the entire rpm range. A pan filled with the oil at the recommended level lost oil pressure at high rpms due to the airation and frothing of the oil by the crankshaft whipping it up. While the same test with 1 less quart of oil kept pressure and made more hp. Granted, this was above 5k rpms and most engines in daily driven vehicles won't be in that rpm range much to cause problems.

On that note, I've never added more then 6qts of oil when doing an oil/filter change, and I have the oil cooler.

Yeah, definitely seems strange that I've had to add almost 7 qts to get it to full. I'm thinking of draining a qt out to see if that helps.

to the op. what radiator did you go with? maybe it's end tank is a bit restrictive? I don't know, just made me think when I was researching dwitts radiators they talked about the number of plates in there for more or less cooling. if you had a auto parts store one maybe it's just a tranny cooler on both ends with bigger fittings?

just thoughts.

I went with the Denso 2219514. In looking at RA for my 2013 Tahoe, it for some reason lists it as the rad specifically for a PPV, but it's the correct one for use with an oil cooler. I've read multiple threads on here about it being a good OEM replacement, without breaking the bank.

The last few posts are about the oil path. Is 100% of the oil going through the cooler after the filter, or does some get diverted before the cooler?
If 100%, it's easy to see why I'd see some pressure drop after adding the cooler. It just seems like I'm seeing too much. I just had the front pumpkin out for my gear change project. I debated dropping the pan then to replace the o-ring, but right before the project I did some road testing that correlated RPM to pressure, and all seemed pretty good. Now I'm wondering if I should have.

I'm going to replace the sensor screen and maybe drain 1/2 to 1 qt out and see where I land after that.

 

[donjetman]

That's called windage (not the same as in gun sights). They make pans with baffles or "windage trays" that bolt-on to help with this oil frothing. It can be a problem and cause loss of pressure at higher rpms

The 07 6.2L L92 in my Denali came from the factory with a windage tray bolted to the mains and a baffles in the pan sump.
Some brands of oil have more anti-foaming additives than others.

 

[j91z28d1]

Yeah, definitely seems strange that I've had to add almost 7 qts to get it to full. I'm thinking of draining a qt out to see if that helps.



I went with the Denso 2219514. In looking at RA for my 2013 Tahoe, it for some reason lists it as the rad specifically for a PPV, but it's the correct one for use with an oil cooler. I've read multiple threads on here about it being a good OEM replacement, without breaking the bank.

The last few posts are about the oil path. Is 100% of the oil going through the cooler after the filter, or does some get diverted before the cooler?
If 100%, it's easy to see why I'd see some pressure drop after adding the cooler. It just seems like I'm seeing too much. I just had the front pumpkin out for my gear change project. I debated dropping the pan then to replace the o-ring, but right before the project I did some road testing that correlated RPM to pressure, and all seemed pretty good. Now I'm wondering if I should have.

I'm going to replace the sensor screen and maybe drain 1/2 to 1 qt out and see where I land after that.

I believe it's all to the filter, with an internal bypass in the filter if needed and then up and to the oil cooler passageway, with the bypass in the aluminum block able to bypass that when flow right gets high enough and then up into the block.

so some sure. you do seem to be seeing more than I'd expect. and that seems to be a radiator everyone uses. so yeah I got nothing.

 

[Grady_Wilson]

With the extended length that the oil has to travel, you would see a drop of a few pounds but 10 sounds like an awful lot.

Just for grins, I would swap in a new oil filter.
Never know, you could have a bad bypass valve.
Just a thought.

 

[West 1]

Wix makes filters, Delco buys them from a variety of sources. I trust Wix, Hastings, they both make filters. You know what you are paying for. I have had several GM trucks with and without the oil cooler lines, never noticed a pressure difference with and without the factory cooler.

 

[swathdiver]

I just finished a build of many replacements and upgrades - documented here. One of the upgrades was the addition of an OEM-style engine oil cooler. I.e. I removed the block off plate, added a set of Dorman replacement lines, and replaced the radiator with a new Denso OEM-style that had the provisions for oil cooler. Great addition in my book, but now my oil pressure is lower. I went from just below 40 psi @2000 rpm, fully warm, to around 30 psi, same conditions. Is that expected? Other than an oil and filter change (same grade and brands as before: Costco synth 5w-30, AC Delco PF63) I didn't change or do anything else that should affect oil pressure.

Any concerns with oil pressure maxing out at around 30-33 psi. I think hot idle is around 15 psi. I have a new spare screen that goes below the oil press sender. I think I will try putting that in first to see if it helps.

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.

 

[OR VietVet]

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]

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

 

[Jetskier77]

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]

NT

 

[Just Fishing]

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.

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]

Accidental double post from previewing post?

 

[Meathead16]

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]

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]

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.

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]

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?