0W-20 vs. 5W-30 - General Motors Warranty Concern

[Monte32]

Hello all,

I'd like some advice. I recently purchased a used 2015 GMC SIERRA DENALI with the 5.3 EcoTec engine. I know GM calls for 0W-20 but I've always run 5W-30 out of habit. I just added Castro Edge 5W-30 to my truck cause I had 8 quarts handy. The Castrol Edge 5W-30 meets Dexos 1. My question is, will my engine be ok by running the 5W-30 instead of the recommended 0W-20?? If I'm doing damage I'll switch to the 0W-20 immediately. I read so many conflicting posts and everyone seems to have a different take on this. I just want to make sure I'm not harming my engine. Also, I live in Houston and mainly operate the vehicle in Houston and South Texas. Thanks

2015 GMC Sierra Denali 4x4

 

[TiredTrucker]

Not sure why it wouldn't. The Ecotec major design is not much different than the Vortec that proceeded it and called for 5w30. About the only major difference is direct injection and some ECM coding. My 2015 Vortec 6.0L still calls for 5w30. The name Ecotec should tell you volumes.... that all the changes were centered around CAFE issues. Hence the call for 0w20 in them. They use the same pistons, rods, crank, valve train, VVT as the 5.3L Vortec did.

I use a 10w30 in mine. I don't even worry about the dexos thing.

 

[KL31]

Dexos is thinner than A3/B4 30 grades and therefore closer to a 20 grade so it's not really far out of whack. Nothing bad will happen.

 

[dwendt44]

Most other GM engines have been using 5W-30 for years, and little has changed inside the 5.3 other than adding the DI heads.

Should be no problems at all.

I personally favor a slightly heavier oil in the southern parts of the U.S.. Triple digit temps. should call for higher weight oil.

MY 2¢

 

[Monte32]

Thanks Tired Trucker. I just wanted to make sure I wasn't causing damage with the 5W-30. The GM folks seem to be adamant about "it has to be 0W-20 cause that was what was used to test and spec the engine". Others have told me that as long as it's Dexos 1 approved I'm ok. I just want to make sure this truck lasts me a good long time.

 

[Monte32]

Thanks guys. I appreciate the 2 cents from everyone. It gets confusing with this whole Dexos thing. I've always used 5W-30. Plus a lot of folks say the only reason we have those 0W-20 and 0W-30 grades is solely for the manufacturers to satisfy CAFE. Others swear by them. So for me it gets confusing. I just know that Mobil 1 5W-30 got me over 280K trouble free miles out of my old 1995 Honda Accord and she was still running great when I finally parted with her.

 

[DevilsRule]

I wouldn't use a weight of oil out of habit especially if a powertrain warranty is still in effect and the manual states to use 0w-20. I would trust the engineers rather than "some folks" who are not engineers and think they know better. I would put the recommended oil in it. Good luck with your new truck

 

[Monte32]

And there we go. That's why I'm confused on this. If I absolutely have to use 0W-20 I will gladly do it. But If I'm gonna pour out and replace/waste 8 quarts of full synthetic 5W-30 I'd just like to know I have a darn good reason to do so. I.E. - I'm causing my engine serious harm with the 5W-30 weight.

 

[barkingspider]

Keep the 5w30 in it for normal oci. I would have no problem using 5 or 10w 30 if it was my truck, but u can Switch back to 0w20 to satisfy warranty

 

[KL31]

But so many engines were specced to run off 5w30 and then back speced to 20. So obviously they all ran fine off 30. But if they re released that engine in another car it would be specced to 20 because emissions.

Every manufacturer wants to claim that 0.1 mpg gain in their unrealistic tests.

 

[crazyoildude]

If it's under warranty use what GM says.. Dont take expensive chances

 

[Merkava_4]

0W-20 will barely get you through warranty and then your engine will be shot.

 

[Monte32]

I wonder if 0W-30 is a good compromise? I know film strength is a concern. 5W-30 is tried and true.

 

[Merkava_4]

GMC truck engines have always preferred 40 weights. Look at the UOA section, wear metals are always less with 40 weights.

 

[Kuato]

Originally Posted By: Monte32
I.E. - I'm causing my engine serious harm with the 5W-30 weight.


No, you are not causing harm. If you're worried down the road, then have a UOA performed. Agree 100% with the CAFE impetus to use the 20 weights.

 

[jayg]

Originally Posted By: Merkava_4
0W-20 will barely get you through warranty and then your engine will be shot.



Please don't listen to this nonsense.

 

[Merkava_4]

Originally Posted By: jayg
Please don't listen to this nonsense.


Apparently you did though.

 

[Rolla07]

I doubt you will have issues with 5w30 but why chance it while under warranty? I wouldnt but again..it depends how comfortable you are chancing it. Unlikely anything bad will happen but if something does Id rather do all in my power to make sure i couldnt be called out on it..

 

[WiskyBadger]

The engineers couldn't have been qualified and there obviously couldn't have been any test time. Use 15w40. Come on man people smarter then us say 0w20.

 

[WiskyBadger]

Originally Posted By: jayg
Originally Posted By: Merkava_4
0W-20 will barely get you through warranty and then your engine will be shot.



Please don't listen to this nonsense.
Yep, I've been gone for a while but Merk hasn't changed one bit.