2025 denali ultimate oil question

J

Jmoney7269

Joined
Aug 15, 2018
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Texas, United states
My wife just bought her dream mommy mobile. She previously had a 2015 tahoe we are going to keep for my oldest girl to drive in a few years. My question is what's so special about that DEXOS 1 oil? Is there a better spec out there? I did all the maintenance on our 15 tahoe and a few years ago for simplicity I just quit buying the dexos oil and just started using 5w40 delvac 1 especially, which is what I use in all of my tractors, my tundra, and nissans. The tahoe has 90k miles on it and zero lifter tick. Immediately after switching to the 5w40 delvac 1 the engines got a lot quieter. Even the cold startup in my tundra went away. So I'm wondering what's the best oil for these 6.2l engines? I've never ran the 0w-20 and never will. One would think a little thicker is better.

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Congrats on the purchase. Not a short wheelbase guy so good job on getting the XL. I would still disable the afm to not chance it, there's a new range disabler that doesn't go to the obd but a section of the harness to disable afm. Dexos is marginally better than SQ I guess. Off the top of my head dexos has a limit of 13% noack instead of 15% for SQ/P. whoopie....

Gm just came out saying the 21-24 needs 0w-40 (I'm sure 5w-40 is fine even if not dexos R rated) but I bet the 2025 also does. I don't think the engines are revised in any way even small. Definitely keep using 40 grade. I'm running 5w-40 in my escalade and outlander sport. Both engines quieted down with the Mitsubishi shutting up so much I can't hear it buzz up the driveway anymore like it did before with 0w-20. The escalade quieted enough to where i can hear the gdi pump but can still hear it go up the driveway. The 10 speed has some whirl noise to it.

That John dude

Thread 'GM now saying to use 0w40 in 21-24 6.2L'

MOD NOTE:
Two threads with same topic have been merged as of 4-25-25 ...
Guy - please check before you post duplicate topics



In the L87 engines GM will be replacing your 0w20 oil with 0w40.
1745535063450.webp
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Last edited:
JavierH19 said:
Congrats on the purchase. Not a short wheelbase guy so good job on getting the XL. I would still disable the afm to not chance it, there's a new range disabler that doesn't go to the obd but a section of the harness to disable afm. Dexos is marginally better than SQ I guess. Off the top of my head dexos has a limit of 13% noack instead of 15% for SQ/P. whoopie....

Gm just came out saying the 21-24 needs 0w-40 (I'm sure 5w-40 is fine even if not dexos R rated) but I bet the 2025 also does. I don't think the engines are revised in any way even small. Definitely keep using 40 grade. I'm running 5w-40 in my escalade and outlander sport. Both engines quieted down with the Mitsubishi shutting up so much I can't hear it buzz up the driveway anymore like it did before with 0w-20. The escalade quieted enough to where i can hear the gdi pump but can still hear it go up the driveway. The 10 speed has some whirl noise to it.

That John dude

Thread 'GM now saying to use 0w40 in 21-24 6.2L'

MOD NOTE:
Two threads with same topic have been merged as of 4-25-25 ...
Guy - please check before you post duplicate topics



In the L87 engines GM will be replacing your 0w20 oil with 0w40.
1745535063450.webp
  • Like
  • Wow
  • Love
Click to expand...
That John dude

Thread 'GM now saying to use 0w40 in 21-24 6.2L'

MOD NOTE:
Two threads with same topic have been merged as of 4-25-25 ...
Guy - please check before you post duplicate topics



In the L87 engines GM will be replacing your 0w20 oil with 0w40.
1745535063450.webp
  • Like
  • Wow
  • Love
JavierH19 said:
Congrats on the purchase. Not a short wheelbase guy so good job on getting the XL. I would still disable the afm to not chance it, there's a new range disabler that doesn't go to the obd but a section of the harness to disable afm. Dexos is marginally better than SQ I guess. Off the top of my head dexos has a limit of 13% noack instead of 15% for SQ/P. whoopie....

Gm just came out saying the 21-24 needs 0w-40 (I'm sure 5w-40 is fine even if not dexos R rated) but I bet the 2025 also does. I don't think the engines are revised in any way even small. Definitely keep using 40 grade. I'm running 5w-40 in my escalade and outlander sport. Both engines quieted down with the Mitsubishi shutting up so much I can't hear it buzz up the driveway anymore like it did before with 0w-20. The escalade quieted enough to where i can hear the gdi pump but can still hear it go up the driveway. The 10 speed has some whirl noise to it.

That John dude

Thread 'GM now saying to use 0w40 in 21-24 6.2L'

MOD NOTE:
Two threads with same topic have been merged as of 4-25-25 ...
Guy - please check before you post duplicate topics



In the L87 engines GM will be replacing your 0w20 oil with 0w40.
1745535063450.webp
  • Like
  • Wow
  • Love
Click to expand...
I suspect that gm is telling people to do that so the "covid engines" last just long enough to make it past warranty so they don't have to replace them.
 
With the latest news of 6.2s going to 0W-40 I'd use DEXOS approved Mobil1 ESP X4 0W-40. Should be a great oil and I assume you could grab it for a good price right off the shelf at Walmart.

Delvac would be way down on my list of oils to use As far as I know Delvac has SL SJ gas certifications thats a 20 year old cert. We have gone past that with SM, SN, SN plus, SP and now SQ is coming out
 
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BobsArmory said:
With the latest news of 6.2s going to 0W-40 I'd use DEXOS approved Mobil1 ESP X4 0W-40. Should be a great oil and I assume you could grab it for a good price right off the shelf at Walmart.

Delvac would be way down on my list of oils to use As far as I know Delvac has SL SJ gas certifications thats a 20 year old cert. We have gone past that with SM, SN, SN plus, SP and now SQ is coming out
Click to expand...
Delvac esp 5w-40 is a great oil, far better than any thin dexos 1 oil. It's SN rated too.
 
Hint-IF you didn't buy an extended warranty at time of purchase now is the time to do so. There are several GM Dealers that sell those online at competitive prices.
Stick with whatever oil GM is recommending at the moment. Don't mess with the warranty on a 75 grand SUV. Get all oil changes at the dealer.
 
CKN said:
Hint-IF you didn't buy an extended warranty at time of purchase now is the time to do so. There are several GM Dealers that sell those online at competitive prices.
Stick with whatever oil GM is recommending at the moment. Don't mess with the warranty on a 75 grand SUV. Get all oil changes at the dealer.
Click to expand...
We bought the extended warranty for ten years. Better add another $43k to that
 
Jmoney which delvac 5w-40 are you using the common delvac esp 5w-40 found everywhere or the not so common non ESP Delvac 1?
 
Jmoney7269 said:
Mobil delvac 1 5w-40 esp synthetic diesel oil

View attachment 275674
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I figured it was the ESP since it's more common. Either one would have been great but the ESP is a bit better for modern engines. The non ESP delvac is higher saps so anything that gets burned would be more harmful to the catalytic converter and on a modern diesel the DPF as well. But that's if it gets burned so if you don't have oil consumption it doesn't matter that much. Lower saps oils also leave less carbon deposits on the intake valves on direct injected engines without port injection but it's not that much either.
 
Just to note, Royal Purple makes a fine 0w-40 also, there other brands can be found Schaeffer's, Amsoil etc,no sense getting hung up on any popular brand, , lots of good choices and viscositys to choose from.
 
Jmoney7269 said:
My wife just bought her dream mommy mobile. She previously had a 2015 tahoe we are going to keep for my oldest girl to drive in a few years. My question is what's so special about that DEXOS 1 oil? Is there a better spec out there? I did all the maintenance on our 15 tahoe and a few years ago for simplicity I just quit buying the dexos oil and just started using 5w40 delvac 1 especially, which is what I use in all of my tractors, my tundra, and nissans. The tahoe has 90k miles on it and zero lifter tick. Immediately after switching to the 5w40 delvac 1 the engines got a lot quieter. Even the cold startup in my tundra went away. So I'm wondering what's the best oil for these 6.2l engines? I've never ran the 0w-20 and never will. One would think a little thicker is better.

View attachment 275649

View attachment 275650

View attachment 275652
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Just wondering why your wife needs a tank like that or do you guys have a few kids to transport around ?
 
Nesterenko said:
Just wondering why your wife needs a tank like that or do you guys have a few kids to transport around ?
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I wouldn’t mind a tank like that, just as soon as I pay off the Acadia and 3500 High Country I bought my daughter.
If you work hard, you get to have nice things.
The 3.6L Acadia is getting 10W40 Duron in a couple weeks. I just filled up some jugs from a 20L pail 15 minutes ago.
 
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Nuclear_42 said:
I’d just run Amsoil Signature 0w-40 or Mobil 1 Super Car both are Dexos R rated and are similar in price.
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Yeah if you spend $118k on a vehicle, and you just paid $12k for the pleasure of driving it off the lot, why are you trying to pinch pennies running cheaper oil??

I'd have gotten a used LX personally. Bulletproof and very luxurious.
 
BobsArmory said:
Mobil website says different.

Mobil link
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Your Mobil link is for the old Ci-4+ blend. Not the current CK-4/SN offering.
Delvac Super 1300 in both 10w30 and 15w40 meets CK-4/SP.
I like the Delvac 0W40 better. Higher density, flash point and HTHS.
Delo is my favourite 5w40 for mixed fleets. It’s in my son’s new to him 2012 6.2L F350.
It was burning a litre of 5w20 every 1,300 kms. Now it has gone over 2,000 kms in the two weeks since I put in the 5w40 delo and it’s still on the full mark.

There should be a couple of free oil changes with a new vehicle purchase from GM. Make sure you have the upgraded 0w40 oil fill cap.
 
tired said:
Yeah if you spend $118k on a vehicle, and you just paid $12k for the pleasure of driving it off the lot, why are you trying to pinch pennies running cheaper oil??

I'd have gotten a used LX personally. Bulletproof and very luxurious.
Click to expand...
Not everyone is into Amsoil. The point I was trying to make is the relative cost. As far as I know Super car is almost $60 a case of 6 quarts. In comparison Signature is $45 a gallon. That small difference made my go Signature for my L84. However nothing wrong with Super car.
 
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