High oil temp while towing: need more PAO/Ester, or more viscosity?

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Nov 23, 2013
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Fly-Over Country, USA
2017 Silverado 5.3 towing 7.5k on a routine basis now. Coolant temps hold at 207, then up to 215-220 until the fans pull it back to 207. I notice when I stop, the oil psi drops to
My question is keep running 0w-20 Dexos (Currently on M1EP) and stay with a higher PAO/Ester oil, or step up a grade to 0w-30/5W-30 for the higher HTHS? I don't give 2 squats about MPG. This is purely for wear protection.

Edit: Almost out of powertrain warranty so viscosity in regards to warranty are moot.
 
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You could always shoot the oil pan with a non-contact thermometer and get an oil temp. reading.

From my understanding you do have an oil cooler, so probably all is fine. Probably also fine sticking with 0w-20 Dexos1gen2 also.
 
No need to worry about wear protection with the 0W20 oil and a heavier weight oil won't necessarily give you better protection. I say you are fine with the 0W20.
 
Modern cars with variable displacement oil pumps try to keep the oil pressure at 15 psi. so as long as you are above that you're still fine. However, piston skirts and rings and cam lobes/followers aren't lubricated under pressure.

I would probably step up a grade, the heat of summer might make the oil even thinner.
 
Originally Posted by Eddddd
No need to worry about wear protection with the 0W20 oil and a heavier weight oil won't necessarily give you better protection. I say you are fine with the 0W20.

Why not? MOFT always wins. Sounds like better protection to me.

And it's a grade, not a weight.
 
How do you know the oil temp is high? All I see are coolant temps in your OP. You have plenty of engine protection with that EP M1 0w-20
 
Originally Posted by kschachn
Originally Posted by Eddddd
No need to worry about wear protection with the 0W20 oil and a heavier weight oil won't necessarily give you better protection. I say you are fine with the 0W20.

Why not? MOFT always wins. Sounds like better protection to me.

And it's a grade, not a weight.


Stand corrected. Heavier grade. There was a discussion about MOFT here on the forum. Here's the link. https://www.bobistheoilguy.com/forums/ubbthreads.php/topics/5118764/1 If going to a heavier grade helps you sleep at night, then do you. It won't hurt the engine. I have a Tundra 5.7, live in South Texas and have towed 7k+ on a regular basis using 0W20. Oil samples show no issues but then again, we are talking about a Toyota.
smile.gif
 
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Originally Posted by MolaKule
Or, use a 5W20 which has less VII and uses slightly higher viscosity base oils.

I'm not sure if that's necessarily the case with mobil1 EP, the 0w20 is like 60-70% PAO on the SDS, the 5w20 is only 5-10%, I assume the rest is probably hydrocracked dino if they don't specify. Since there's so much PAO in the 0w20 isn't it possible that since it uses a presumably higher quality base oil that it might actually have a lower VII content than the 5w20 variant.
 
Originally Posted by zuluplus30

Edit: Almost out of powertrain warranty so viscosity in regards to warranty are moot.
Perhaps that it has made it this far serves thusly for some as partial validation?
 
Originally Posted by splinter
Originally Posted by zuluplus30

Edit: Almost out of powertrain warranty so viscosity in regards to warranty are moot.
Perhaps that it has made it this far serves thusly for some as partial validation?


60K miles is hardly a nod to longevity.
 
Originally Posted by Eddddd
Stand corrected. Heavier grade. There was a discussion about MOFT here on the forum. Here's the link. https://www.bobistheoilguy.com/forums/ubbthreads.php/topics/5118764/1 If going to a heavier grade helps you sleep at night, then do you. It won't hurt the engine. I have a Tundra 5.7, live in South Texas and have towed 7k+ on a regular basis using 0W20. Oil samples show no issues but then again, we are talking about a Toyota.
smile.gif


I wouldn't expect it to.
 
Originally Posted by PowerSurge
How do you know the oil temp is high? All I see are coolant temps in your OP. You have plenty of engine protection with that EP M1 0w-20


Pure assumption, except under normal driving the oil pressure sits about 30-35 psi at idle. After towing, it sits about 19-20 during idle. My assumption is the oil is hot and thin.
 
Originally Posted by zuluplus30
Originally Posted by PowerSurge
How do you know the oil temp is high? All I see are coolant temps in your OP. You have plenty of engine protection with that EP M1 0w-20


Pure assumption, except under normal driving the oil pressure sits about 30-35 psi at idle. After towing, it sits about 19-20 during idle. My assumption is the oil is hot and thin.


If you're going by the factory oil pressure gauge, I wouldn't. They are notoriously inaccurate.
 
Originally Posted by PowerSurge
Originally Posted by zuluplus30
Originally Posted by PowerSurge
How do you know the oil temp is high? All I see are coolant temps in your OP. You have plenty of engine protection with that EP M1 0w-20


Pure assumption, except under normal driving the oil pressure sits about 30-35 psi at idle. After towing, it sits about 19-20 during idle. My assumption is the oil is hot and thin.


If you're going by the factory oil pressure gauge, I wouldn't. They are notoriously inaccurate.


Agree. So discard the actual numbers, but the disparity in idle oil pressure between towing and normal driving remains.
 
Originally Posted by zuluplus30
Originally Posted by PowerSurge
Originally Posted by zuluplus30
Originally Posted by PowerSurge
How do you know the oil temp is high? All I see are coolant temps in your OP. You have plenty of engine protection with that EP M1 0w-20


Pure assumption, except under normal driving the oil pressure sits about 30-35 psi at idle. After towing, it sits about 19-20 during idle. My assumption is the oil is hot and thin.


If you're going by the factory oil pressure gauge, I wouldn't. They are notoriously inaccurate.


Agree. So discard the actual numbers, but the disparity in idle oil pressure between towing and normal driving remains.


That engine has a two-stage pump. Any viscosity oil is going to be thinner after towing with a lower oil pressure. That doesn't mean the oil's temp is too high or that it isn't protecting the engine.
 
If you are running M1 EP 0w20 then you can't get much more PAO and ester than that.

I'm not sure of the thinking that PAO will help with higher temperatures. I wouldn't change anything. You're running a quality oil right now.
 
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