OEM oil cooler block discoveries....

[j91z28d1]

I'm not sure if it's the same but that block has been talked about on
the corvette forums a lot. as I understand it, at least on the cars it's a psi bypass, so at high volume of oil flow when the oil cooler became a 7psi restriction, it opens and bypassed it. small 3/8 lines on a 7k rpm engine.

I've seem part numbers posted for the replacement valve inside. I seem to remember it looks the same as you found for temp.

funny the guys that daily drive their cars when it's cold would love to have a thermostats in theirs, they think if they don't see 200deg oil Temps then they are doing engine damage, so they remove the stock oil coolers.

 

[j91z28d1]

I believe this is the bypass valve

Amazon.com: GM Genuine Parts 25161284 Engine Oil Cooler Bypass Valve : Automotive

Buy GM Genuine Parts 25161284 Engine Oil Cooler Bypass Valve: Accessories - Amazon.com ✓ FREE DELIVERY possible on eligible purchases

a.co

 

[rdezs]

That's interesting. I still have it on the bench, tomorrow afternoon I will drop it in some hot water before the wife gets home, on the stove and see if it moves at a certain temperature.

 

[rdezs]

I believe this is the bypass valve

Amazon.com: GM Genuine Parts 25161284 Engine Oil Cooler Bypass Valve : Automotive

Buy GM Genuine Parts 25161284 Engine Oil Cooler Bypass Valve: Accessories - Amazon.com ✓ FREE DELIVERY possible on eligible purchases

a.co

That matches exactly what I have. The question is, does it bypass based on pressure or by temperature. Science experiment tomorrow, stay tuned

 

[j91z28d1]

if temp, you might have found something for corvette guys. the ls7 cars had a big front mount and didn't loop thru the radiator. so they worry about over cooling. where mine loops thru the radiator before going to the front mount. seems to make for very stable oil Temps like that.

oil is on the hot side, tranny on the cool. but oil can handle much higher Temps. it's nice to have 200deg oil Temps but I've spent a good amount of time at 300deg oil Temps at track days before cooler mods on the ls3 car with no side effects according to oil samples. no signs of extra wear or excessive oil break down. plenty of life left in it according to them. I changed it as soon as I got home haha

 

[OBSandaNNBS]

I'm not sure if it's the same but that block has been talked about on
the corvette forums a lot. as I understand it, at least on the cars it's a psi bypass, so at high volume of oil flow when the oil cooler became a 7psi restriction, it opens and bypassed it. small 3/8 lines on a 7k rpm engine.

I've seem part numbers posted for the replacement valve inside. I seem to remember it looks the same as you found for temp.

funny the guys that daily drive their cars when it's cold would love to have a thermostats in theirs, they think if they don't see 200deg oil Temps then they are doing engine damage, so they remove the stock oil coolers.

Ooooh, plot twist! I'm placing my chips on they are different for the truck vs vette application

 

[rdezs]

Drum roll please..... The one I disassembled is a genuine GM for the 2014 Escalade. It closes right at about 200°F.

That's an interesting point about the Corvettes. Really, they use 3/8 oil cooler line? That's not a typo? Because these oil cooler lines are 1/2". (And the flexible hose part that's crimped on is 1/2" ID.)

If the Corvettes are using a smaller diameter for the oil cooler lines, I can see that creating a pressure issue at high RPM. So perhaps for the cars it is based on pressure to bypass the cooler. Very little documentation from GM on this subject.

Just had a thought regarding the postings where people have low oil pressure hot at idle in drive. (Say 15 to 18 PSI) If their thermostat was stuck open, it would be bypassing the oil cooler. It would really pay to have an oil temperature gauge to know for sure. I have no clue how hot the oil might get without the oil cooler. And how much thinner is the oil going to be, resulting in a lower PSI, and at what temperatures?

Think I'll just stick with aftermarket at this point, no thermostat and just always run through the oil cooler.

 

[Foggy]

This thread rocks !!!!
Never even knew about this "weird" "unnecessary" TStat thing
(prob useful in alaska or north dakota, maybe )

 

[rdezs]

Now that is a good point. If you're Prudoe Bay Alaska.... They probably don't even run the oil cooler

 

[Foggy]

Drum roll please..... The one I disassembled is a genuine GM for the 2014 Escalade. It closes right at about 200°F.

That's an interesting point about the Corvettes. Really, they use 3/8 oil cooler line? That's not a typo? Because these oil cooler lines are 1/2". (And the flexible hose part that's crimped on is 1/2" ID.)

If the Corvettes are using a smaller diameter for the oil cooler lines, I can see that creating a pressure issue at high RPM. So perhaps for the cars it is based on pressure to bypass the cooler. Very little documentation from GM on this subject.

Just had a thought regarding the postings where people have low oil pressure hot at idle in drive. (Say 15 to 18 PSI) If their thermostat was stuck open, it would be bypassing the oil cooler. It would really pay to have an oil temperature gauge to know for sure. I have no clue how hot the oil might get without the oil cooler. And how much thinner is the oil going to be, resulting in a lower PSI, and at what temperatures?

Think I'll just stick with aftermarket at this point, no thermostat and just always run through the oil cooler.

Well I guess I now have a new project to complete on my Yukon !!!!
I think I'm gonna like you did and just go w. AN lines and go thru the radiator cooler
full time !!!

 

[rdezs]

You know that little thermostat is rather flimsy, and it does have some small pieces to it. It makes me ponder if sometimes they come apart and get stuck in the oil system somewhere. I think it's better to just keep it simple.

 

[rdezs]

I think it just occurred to me why they did this. Think about the CAFE fuel economy standards. Keeping the oil at 200° minimum temperature will be less resistance on the oil pump.... And might even make a half mile per gallon improvement in mileage. That's a big number for GM and the government bureaucracy that drives them to do this sort of thing. Lol, I don't think we are ever expected to know about it.

 

[swathdiver]

I think it just occurred to me why they did this. Think about the CAFE fuel economy standards. Keeping the oil at 200° minimum temperature will be less resistance on the oil pump.... And might even make a half mile per gallon improvement in mileage. That's a big number for GM and the government bureaucracy that drives them to do this sort of thing. Lol, I don't think we are ever expected to know about it.

You're probably right, same reason they used thermostat on the 6L80 with the K2s.

Good news though, CAFE is dead and buried.

 

[OBSandaNNBS]

I think it just occurred to me why they did this. Think about the CAFE fuel economy standards. Keeping the oil at 200° minimum temperature will be less resistance on the oil pump.... And might even make a half mile per gallon improvement in mileage. That's a big number for GM and the government bureaucracy that drives them to do this sort of thing. Lol, I don't think we are ever expected to know about it.

Surprising/not surprising how often it comes back to CAFE! Like @Foggy said, great thread, thanks for the info! I'll let you know what my Tstat's condition is when I swap it this week.

 

[j91z28d1]

Drum roll please..... The one I disassembled is a genuine GM for the 2014 Escalade. It closes right at about 200°F.

That's an interesting point about the Corvettes. Really, they use 3/8 oil cooler line? That's not a typo? Because these oil cooler lines are 1/2". (And the flexible hose part that's crimped on is 1/2" ID.)

If the Corvettes are using a smaller diameter for the oil cooler lines, I can see that creating a pressure issue at high RPM. So perhaps for the cars it is based on pressure to bypass the cooler. Very little documentation from GM on this subject.

Just had a thought regarding the postings where people have low oil pressure hot at idle in drive. (Say 15 to 18 PSI) If their thermostat was stuck open, it would be bypassing the oil cooler. It would really pay to have an oil temperature gauge to know for sure. I have no clue how hot the oil might get without the oil cooler. And how much thinner is the oil going to be, resulting in a lower PSI, and at what temperatures?

Think I'll just stick with aftermarket at this point, no thermostat and just always run through the oil cooler.

interesting.. these are the c6 ones.. it's been a while since I messed with them, I'm pretty sure they are metric sized but basically 3/8ID. I've have to double check.

sounds like you can have temp or pressure bypass. that could be useful for guys with big front mount oil coolers that worry about that sort of thing. they think anything less than 220 oil temp moisture builds up and rusts the inside of the engine or something.

05-13 Engine Oil Cooler Hose Assembly

05-13 Engine Oil Cooler Hose Assembly

www.zip-corvette.com

 

[Actifenpleinair]

..... I've also read many posts where people delete their oil cooler and report oil temperatures run the same. Most likely it's because that thermostat was stuck and no oil was going to the cooler.

With no oil temperature gauge on most models, this is a bit of an irritant. But if you use your vehicle to tow quite a bit, it can be a real problem.

Here's what I converted to last year.... Put one on the 2014 Escalade and one on the 2003 Hummer.
View attachment 460893

Does your new one have a thermostat? Was answered earlier....
I am in the cold elevations often and I like the warm up the oil quickly fxn of a working thermostat, wonder if my '07 denali has it, and if it does, i suspect it may be stuck open... was towing heavy and fast at elevation and saw oil temps of 260. Attached is a TorquePro screenshot oil and coolant temp mid upper right.

 

[rdezs]

That is about the only way to diagnose a stuck thermostat.... By looking at the actual oil temperatures

 

[j91z28d1]

did some years get a real oil temp sensor?

mine didn't. it's just some math based on other to things.

 

[rdezs]

You'll have to tee off the OEM oil pressure sending unit location to put an oil temperature sending unit. You'll be able to watch fluctuations in temperature based on which way that thermostat is sending the oil, if it's working.

 

[donjetman]

Does your new one have a thermostat? Was answered earlier....
I am in the cold elevations often and I like the warm up the oil quickly fxn of a working thermostat, wonder if my '07 denali has it, and if it does, i suspect it may be stuck open... was towing heavy and fast at elevation and saw oil temps of 260. Attached is a TorquePro screenshot oil and coolant temp mid upper right.

My 07 Denali doesn't have an oil cooler.