Oil pressure drop after addition of OEM Oil Cooler?

[DaveO9]

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.

 

[mikez71]

Seems like my pressure might have dropped ~2psi possibly after adding filter. (Could be in my head)

Pressures seem ok, but if you're sure it's dropped almost 10psi..
Make sure none of the hoses are kinked.. They are pretty short so that is unlikely I suppose..

 

[j91z28d1]

huh.. I don't have any reference because I've not added one, but the thing I've seen on other gm cars with a oil cooler is they have a relief valve in the aluminum block that mounds above the oil filter to the engine block. did you happen to notice if your Dorman set had this. I'll try to look up a pic but if I'm remember right, at high flow rates when the restricting get above 7psi it allows it to bypass the cooler.

05-13 Engine Oil Cooler Hose Assembly

05-13 Engine Oil Cooler Hose Assembly

www.zip-corvette.com

I don't know what the Tahoe might have stock setting. if you look at the block in this pick is the little screw in part on the back side.

 

[OR VietVet]

Strange that it would happen "after the cooler lines installed". I have heard bad things about the AC Delco PF63. Yes, replace the screen and see what happens. I also had not thought about this and maybe I am over thinking, do you need a bit more oil for the lines capacity?

 

[gooffeyguy]

huh.. I don't have any reference because I've not added one, but the thing I've seen on other gm cars with a oil cooler is they have a relief valve in the aluminum block that mounds above the oil filter to the engine block. did you happen to notice if your Dorman set had this. I'll try to look up a pic but if I'm remember right, at high flow rates when the restricting get above 7psi it allows it to bypass the cooler.

05-13 Engine Oil Cooler Hose Assembly

05-13 Engine Oil Cooler Hose Assembly

www.zip-corvette.com

I don't know what the Tahoe might have stock setting. if you look at the block in this pick is the little screw in part on the back side.

There's no adjustment valve on an OE one.

Dang that's expensive, guess it's a vette thing, lol. More than likely because of the valve?

A GM oil cooler line from RockAuto is $67

 

[j91z28d1]

There's no adjustment valve on an OE one.

Dang that's expensive, guess it's a vette thing, lol. More than likely because of the valve?

A GM oil cooler line from RockAuto is $67

View attachment 436685

if that's they truck link, the valve there. arrow pointing to it.

 

[j91z28d1]

but yes. the vette tax is real.

and annoying haha.

 

[DaveO9]

Strange that it would happen "after the cooler lines installed". I have heard bad things about the AC Delco PF63. Yes, replace the screen and see what happens. I also had not thought about this and maybe I am over thinking, do you need a bit more oil for the lines capacity?

Will do on the screen - next on the list. I remember on my '09 Tahoe, the PF63 actually improved oil pressure. And that one had the oil cooler from factory. I like the PF63 since it has more capacity. But I have a PF48E laying around that I could install just to see if it helps? Or do you recommend a different brand? I know some on here prefer Wix. Yeah, adding the cooler and lines (and taller filter) I'm at 6.5-7 quarts for the first oil change. I'm sure next one will be less.

if that's they truck link, the valve there. arrow pointing to it.

I used a Dorman set for the lines. I'm not sure why I didn't go with the GM ones, wish I would have now. But the Dorman does have that same valve. Should I try and adjust?

 

[j91z28d1]

far as I know there's no adjustments. I was just thinking it might not have it at all.

if you're really curious there's a test port on the drivers side of the block in the front. you could test the oil pressure right off the pump and then compare it to the sensor port up tops with a mechanical gauge.

 

[OR VietVet]

Will do on the screen - next on the list. I remember on my '09 Tahoe, the PF63 actually improved oil pressure. And that one had the oil cooler from factory. I like the PF63 since it has more capacity. But I have a PF48E laying around that I could install just to see if it helps? Or do you recommend a different brand? I know some on here prefer Wix. Yeah, adding the cooler and lines (and taller filter) I'm at 6.5-7 quarts for the first oil change. I'm sure next one will be less.

I used a Dorman set for the lines. I'm not sure why I didn't go with the GM ones, wish I would have now. But the Dorman does have that same valve. Should I try and adjust?

I am a WIX fan. The shorter AC Delco filter will just build oil pressure quicker but have less filtering capacity. I just like WIX over AC Delco when it comes to oil filters.

 

[gooffeyguy]

if that's they truck link, the valve there. arrow pointing to it.

I never knew that was a valve. I know it's not adjustable and that there is an o-ring under it that can start leaking and need replacing. I just thought it was a blocked off port for some unknown application, lol

Most people on here don't know what that port is for either, it's been discussed in other threads. Glad you shared this knowledge with us, and now we know

 

[Just Fishing]

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.

 

[strutaeng]

I rebuilt the engine on my suburban's LQ4 a few months ago and haven't reinstalled the oil cooler lines. It had them originally.

I was going to buy the Dorman, which has something they call "improved design" or something, but decided to simply go back with the GM Genuine. My old ones had started to deep a tiny bit. But I haven't installed it yet.

In theory yes, there should be a bit lower pressure because the oil has make it's way through the cooler and there's more friction. But 10 psi seems a little too much. IDK.

 

[gooffeyguy]

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

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

 

[Charlie207]

Will do on the screen - next on the list. I remember on my '09 Tahoe, the PF63 actually improved oil pressure. And that one had the oil cooler from factory. I like the PF63 since it has more capacity. But I have a PF48E laying around that I could install just to see if it helps? Or do you recommend a different brand? I know some on here prefer Wix. Yeah, adding the cooler and lines (and taller filter) I'm at 6.5-7 quarts for the first oil change. I'm sure next one will be less.

I used a Dorman set for the lines. I'm not sure why I didn't go with the GM ones, wish I would have now. But the Dorman does have that same valve. Should I try and adjust?

2014 and older do not have adjustable valves. Those are in the 2015 and up, so you have nothing to adjust, or worry about.

 

[gooffeyguy]

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.

 

[j91z28d1]

I never knew that was a valve. I know it's not adjustable and that there is an o-ring under it that can start leaking and need replacing. I just thought it was a blocked off port for some unknown application, lol

Most people on here don't know what that port is for either, it's been discussed in other threads. Glad you shared this knowledge with us, and now we know

ahh I hadn't see the threads.

I believe this is valve under itself and can be replaced.

https://www.carparts.com/details/Chevrolet/Corvette/AC_Delco/Oil_Cooler_Valve/2013/AC25014694.html?TID=gglpla&origin=pla&utm_source=google&utm_medium=pla&utm_campaign=20878785539&gad_source=1&gclid=CjwKCAjwodC2BhAHEiwAE67hJGp3O4vw4P6HkMMZuW_ciVorEa2ztbFWqvf5gCcPAprvZ3nwnMgnqhoCA60QAvD_BwE&gclsrc=aw.ds

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.

 

[j91z28d1]

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.

not that's it's relvent here, but as an odd thing. c6 corvette owners manual calls for adding an extra qt of oil over the full on the dipstick amount if it's going to be driven hard. I didn't believe it till I downloaded the owners manual and read it myself. very weird huh. I've done it, and then said eh and drove it a 1000 miles home without removing or. didn't see any oil pressure issues on the way, but then again looking back, it probably burned half a qt at the track lol. back before I know horrible the pvc system is at drinking tons of oil at high vacuum.

theory goes guys would take their stock cars to what corvette guys call "high performance driving academy" or something lame like that because they believe insurance will cover their car if they crash it because it's not racing if it's untimed, it just teaching. lol. but it's a track day and they got low oil pressure warnings and blown up motors under warranty. so gm has a delay in how long it can see 0 oil pressure before dash lights come on, it's even defined in hptuners so you adjust the time. that and add a extra qt of oil was their fix for the base cars.

built a half dry sump setup for the zo6's, which still rod knock of driven hard enough on long left hand sweepers, but it's not talked about outside if track guys because negative things would hurt the valve.

ls oil systems are kinda a mess for something that seems so simple.

 

[gooffeyguy]

ahh I hadn't see the threads.

I believe this is valve under itself and can be replaced.

https://www.carparts.com/details/Chevrolet/Corvette/AC_Delco/Oil_Cooler_Valve/2013/AC25014694.html?TID=gglpla&origin=pla&utm_source=google&utm_medium=pla&utm_campaign=20878785539&gad_source=1&gclid=CjwKCAjwodC2BhAHEiwAE67hJGp3O4vw4P6HkMMZuW_ciVorEa2ztbFWqvf5gCcPAprvZ3nwnMgnqhoCA60QAvD_BwE&gclsrc=aw.ds

Weird, the listed vehicles this valve fits is 80s-mid 90s trucks/suvs and 2006-2014 vettes.

I wonder what's different on ~2000+ trucks/SUVs that this isn't used.

 

[gooffeyguy]

not that's it's relvent here, but as an odd thing. c6 corvette owners manual calls for adding an extra qt of oil over the full on the dipstick amount if it's going to be driven hard. I didn't believe it till I downloaded the owners manual and read it myself. very weird huh. I've done it, and then said eh and drove it a 1000 miles home without removing or. didn't see any oil pressure issues on the way, but then again looking back, it probably burned half a qt at the track lol. back before I know horrible the pvc system is at drinking tons of oil at high vacuum.

theory goes guys would take their stock cars to what corvette guys call "high performance driving academy" or something lame like that because they believe insurance will cover their car if they crash it because it's not racing if it's untimed, it just teaching. lol. but it's a track day and they got low oil pressure warnings and blown up motors under warranty. so gm has a delay in how long it can see 0 oil pressure before dash lights come on, it's even defined in hptuners so you adjust the time. that and add a extra qt of oil was their fix for the base cars.

built a half dry sump setup for the zo6's, which still rod knock of driven hard enough on long left hand sweepers, but it's not talked about outside if track guys because negative things would hurt the valve.

ls oil systems are kinda a mess for something that seems so simple.

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.