Oil pressure drop after addition of OEM Oil Cooler?

[mikez71]

(Has anyone had success in replacing the lines without removing either?)

Yes, I installed oil cooler and transmission cooler lines without removing any of that. (2012 4WD)
Was not difficult, jacked up the back of truck as well as front to remove/install from the rear.

 

[Geotrash]

One thing I haven't seen mentioned is the possibility that there is still some air trapped in the new cooler, which would make it harder to sustain pressure. Not sure what to do about it except to say keep driving it to see if over time any air bubbles will get pushed through the system.

 

[Just Fishing]

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.



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

Yeah, the intake needs to come off.
When reinstalling makes sure you have a torque wrench that can handle NM, don't over torque the intake manifold.
I think it's like 8ft lbs or less.

You can probably stick your hand under the intake with a wrench to just check the valley cover bolts.
you might even be able to get most of them w/o touching the intake, probably pull the air box and tube to get access.

If you do pull the intake, might as well do the oil pressure sensor at the rear while you're there.
There is also a screen under the sensor, get that too!
Don't cheap out.

With the intake off, you can also try and dump the oil from it.
on mine it seemed like there was a catch can area of sorts, oil poured out of it!
I carefully pulled the map sensor and degreased and brushed that thing clean before reinstalling.

 

[donjetman]

Yeah, the intake needs to come off.
When reinstalling makes sure you have a torque wrench that can handle NM, don't over torque the intake manifold.
I think it's like 8ft lbs or less.

You can probably stick your hand under the intake with a wrench to just check the valley cover bolts.
you might even be able to get most of them w/o touching the intake, probably pull the air box and tube to get access.

If you do pull the intake, might as well do the oil pressure sensor at the rear while you're there.
There is also a screen under the sensor, get that too!
Don't cheap out.

With the intake off, you can also try and dump the oil from it.
on mine it seemed like there was a catch can area of sorts, oil poured out of it!
I carefully pulled the map sensor and degreased and brushed that thing clean before reinstalling.

Intake mainifold bolts: first pass=44 in lbs, second pass=89 in lbs.

My valley cover bolts=18 ft lbs; mine were still tight when I pulled off my intake.

 

[DaveO9]

Yeah, the intake needs to come off.
When reinstalling makes sure you have a torque wrench that can handle NM, don't over torque the intake manifold.
I think it's like 8ft lbs or less.

You can probably stick your hand under the intake with a wrench to just check the valley cover bolts.
you might even be able to get most of them w/o touching the intake, probably pull the air box and tube to get access.

If you do pull the intake, might as well do the oil pressure sensor at the rear while you're there.
There is also a screen under the sensor, get that too!
Don't cheap out.

With the intake off, you can also try and dump the oil from it.
on mine it seemed like there was a catch can area of sorts, oil poured out of it!
I carefully pulled the map sensor and degreased and brushed that thing clean before reinstalling.

OK, I'm talked into it. I was already going to replace the screen, and already have it, but I think I'll pull the manifold and check those bolts. It will make replacing the screen much easier, too. And I just ordered a GM oil press sensor, so will be replacing that too. Thanks!

 

[swathdiver]

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.

The LC9s oil pressure bypass spring keeps the oil pressure at about 33 psi under load once the engine is warmed up. On mine, there's some space between the needle and the 40 psi mark. I think the Tech-2 said 37-38 psi once.

Now, having hit 200K miles, she idles at about 23-25 psi in gear at a stoplight with oil that's 3200 miles old. More often than not lately, the needle in this condition is hitting the 20 psi mark.

 

[j91z28d1]

I'm curious if someone with low pressure would be brave enough to put the hybrid variable displacement pump in and see 40 to 50psi at all times ha. I mean the minimum spec from gm is 37psi at 1000rpm hot where the standard is like 7psi hot.

12623423 is the part number.

 

[DaveO9]

Yeah, the intake needs to come off.
When reinstalling makes sure you have a torque wrench that can handle NM, don't over torque the intake manifold.
I think it's like 8ft lbs or less.

You can probably stick your hand under the intake with a wrench to just check the valley cover bolts.
you might even be able to get most of them w/o touching the intake, probably pull the air box and tube to get access.

If you do pull the intake, might as well do the oil pressure sensor at the rear while you're there.
There is also a screen under the sensor, get that too!
Don't cheap out.

With the intake off, you can also try and dump the oil from it.
on mine it seemed like there was a catch can area of sorts, oil poured out of it!
I carefully pulled the map sensor and degreased and brushed that thing clean before reinstalling.

will I need to replace the intake manifold gaskets if I remove it? I checked the front bolts on the valley cover today - I can turn them with my fingers.

 

[strutaeng]

will I need to replace the intake manifold gaskets if I remove it? I checked the front bolts on the valley cover today - I can turn them with my fingers.

Remove the intake and replace the valley cover gasket. Probably a good time to clean everything under there.

You can also see the rear of the engine near the oil pressure sender to see if there's any leak back there.

 

[Just Fishing]

will I need to replace the intake manifold gaskets if I remove it? I checked the front bolts on the valley cover today - I can turn them with my fingers.

You don't have to, but it's a good idea to do it if you're planning to dive right in.
Fel-Pro makes a gasket for the AFM manifold, it also includes the seals/orings for the afm towers.

 

[j91z28d1]

is your afm active? if not, it's good time to disable the mechanical side of it. if you have it tuned off and not just a obd plug in disabler thingy

 

[DaveO9]

is your afm active? if not, it's good time to disable the mechanical side of it. if you have it tuned off and not just a obd plug in disabler thingy

That was going to be my next question! I have AFM turned off in tune. So what all does that entail? Just removing the solenoids and then replacing valley cover with a flat one? I ordered some other stuff in Amazon this morning and threw in a $20 feel-pro perimeter gasket just in case I can do that. Maybe I could get a flat cover from pick-n-pull

 

[j91z28d1]

That was going to be my next question! I have AFM turned off in tune. So what all does that entail? Just removing the solenoids and then replacing valley cover with a flat one? I ordered some other stuff in Amazon this morning and threw in a $20 feel-pro perimeter gasket just in case I can do that. Maybe I could get a flat cover from pick-n-pull

if you still have the afm lifters installed even thou they are not active you can not add a flat cover. they lifters will be stuck closed within no time.

 

[j91z28d1]

there's youtube videos explaining it and a guy here did it, having to release a stuck lifter. the afm lifters have to vent back thru those lifter valve holes, not much but just a little bit. any build up of oil, from bypassing internally or around the lifter bore will pressurize the activation port if you put the smooth valve cover on it. the way you try to prevent that from happening is there's a block off plug you put under the oil pressure sensor, that blocks the incoming passage way for oil to the solenoids(incase one leaks), and then the gasket on the port in the block that goes down to the afm lifters, you cut that gasket, so that any oil coming up can vent and not build up pressure. at that point the afm lifters should not active accidentally and stay locked.

if you replace those lifters with standard lifters, then you block off those ports and you might get a touch better oil pressure. but doing it on the afm lifters is a recipe for disaster

 

[DaveO9]

Got it thanks. I’ll save mechanical AFM delete for another time, probably do the whole shebang then with cam upgrade. Hoping to pull the manifold tonight and do an assessment on which gaskets I need to replace, if any. I’ve spent a ton of $$ on this thing in the last couple months. Starting to get some raised eyebrows from the family accountant. ;-)

 

[DaveO9]

Last night and tonight I did the manifold removal and reinstall. Replaced the screen filter and the oil pressure sensor (GM). Didn't replace any of the gaskets. There was no sign of leaking from the valley cover so I didn't remove it. The front bolts were all loose, but the back ones were still tight. Put a drop of blue loctite on the loose ones and retorqued all the bolts. Manifold gaskets looked fine, so I didn't replace them. Got it all back together tonight and it does seem that I gained 3-5 psi at most RPMs. Once up to temp, I was seeing more than 35 psi at 2k and just a few psi less at 1600 cruise rpm. Idle is good, too, at just a hair under 20. Granted it was a cooler day in the PNW, and I didn't drive it far, but it was giving those numbers after it had warmed up to normal coolant temp of 210.

Unless after a longer drive/warmer ambient I see much worse, I am calling this a wrap. Thanks for all the input and advice!