Which engine - 5.3, 6.2 or 3.0?

[redwngr]

I usually don't take pics, so here's 28,000 miles of mine

[JeffKirk]

Sorry, double post. 

 

That is impressive!  I get that it's a long highway drive, but still, 29.6 has bragging rights.  May have me thinking about the LZO next time.  The torque is right where I need it for towing the boat, but I wonder how the power feels compared to my 6.2?  I haven't driven the Diesel to compare.  My silly attitude was focused on the horsepower and torque when I ordered my 2024.  I do love the 6.2 though... 

Edited March 5, 2025 by JeffKirk

[JeffKirk]

9 hours ago, redwngr said:

Here's one of mine. 

One tankful.

Filled near home, crossed at Sarnia-Port Huron and refilled somewhere in NC on the way to Raleigh.  

 

 

 

That is impressive!  I get that it's a long highway drive, but still, 29.6 has bragging rights.  May have me thinking about the LZO next time.  The torque is right where I need it for towing the boat, but I wonder how the power feels compared to my 6.2?  I haven't driven the Diesel to compare.  My silly attitude was focused on the horsepower and torque when I ordered my 2024.  I do love the 6.2 though... 

[Jus Cruisin]

I decided to order a 3.0l this morning. I like the 6.2l but I don't trust it. If there wasn't a big delay on repairs, I wouldn't have any issues. But right now, if one goes, it'll be weeks waiting for a replacement. 

[Z71RAD88]

3 minutes ago, Jus Cruisin said:

I decided to order a 3.0l this morning. I like the 6.2l but I don't trust it. If there wasn't a big delay on repairs, I wouldn't have any issues. But right now, if one goes, it'll be weeks waiting for a replacement. 

Very much the same reason I’ve shifted away from the 6.2 myself which is a shame. 

[Srode1]

I was getting ready to start shopping for a replacement for our '15 6.2  and decided to keep it for a while after doing some research on some of the reliability problems with the current drivetrain choices. 

 

The rear drive on the 3.0 engine for the fuel and oil pump along with the potential for ongoing oil consumption problem which GM says is normal isn't making me want that despite great fuel economy.  I've had a diesel before although older LB7, they are nice till they aren't is my experience.  Fuel additives in the Winter, gelling when it's super cold, can be harder to find fuel (good fuel), and special oil now for the 3.0 that is hard to find its all just a bit too much for me to go after right now.   

 

The 6.2 DFM and bearing failures is a non starter till GM get's it resolved and I'm not aware of any solutions yet. 

 

Then there's the 10 speed valve body wear issues that both motors could have - I think I'm better off sticking with what I have for a while longer.  Seems they should have just used the old 5 speed Allision used in the HD trucks which was bullet proof.  

 

I do realize squeaky wheels rise to the top but reliability is king and I'm not willing to throw down 60-80k on a truck that might be a PIA to own when what I have just works (knock on wood). 

[newdude]

5 minutes ago, Srode1 said:

The rear drive on the 3.0 engine for the fuel and oil pump along with the potential for ongoing oil consumption problem which GM says is normal isn't making me want that despite great fuel economy.  I've had a diesel before although older LB7, they are nice till they aren't is my experience.  Fuel additives in the Winter, gelling when it's super cold, can be harder to find fuel (good fuel), and special oil now for the 3.0 that is hard to find its all just a bit too much for me to go after right now.   

 

 

 

200k mi interval on the belt now.

 

As for oil consumption, IMO, its people buying these and not actually using them or idle the crap out of them or driving 1-5 miles to work at city speeds.  Rings not seating or rings getting stuck with carbon build up.  

 

Same with the 2.7, 5.3 and 6.2 consumption.  My 2.7 had a leak, fixed it and no consumption between changes, if any its maybe 1/8 qt at the most.  My leak would do about 1qt in 3000mi.  My 2018 5.3 I had, again, burned/consumed zero or near zero.  

Edited March 5, 2025 by newdude

[Srode1]

15 hours ago, newdude said:

 

 

200k mi interval on the belt now.

 

As for oil consumption, IMO, its people buying these and not actually using them or idle the crap out of them or driving 1-5 miles to work at city speeds.  Rings not seating or rings getting stuck with carbon build up.  

 

Same with the 2.7, 5.3 and 6.2 consumption.  My 2.7 had a leak, fixed it and no consumption between changes, if any its maybe 1/8 qt at the most.  My leak would do about 1qt in 3000mi.  My 2018 5.3 I had, again, burned/consumed zero or near zero.  

I'm not trying to talk anyone out of buying one,  just sharing my reasoning for not buying a new one now.  For me it's just not a good fit for the way I  use our truck even though it get's great fuel economy.  

 

The 200K mi service interval on that belt for a $3500 repair item will probably impact the resale if you keep the truck well past it's warranty.  

 

Diesels aren't good for shorter trips I agree, they don't warm up and in the Winter it takes a long time to warm up and get heat in the cab even with a grill cover.  Do I use my truck for short trips - yep daily.  Do I take long road trips yep, and that's where this engine would shine but I don't do that more than a few times a year.  One of those will be towing and in the days before DEF that's where a diesel would definitely shine and thats why I did own one.  Towing in a truck that needs DEF will still be more economical I'm sure but it's something else a person needs to manage and any of the hands on reviews I seen agree, towing will increase DEF consumption a lot.  When I get in the truck to tow our 5000lb boat and trailer 1200 miles one way, I don't want to need to carry gallons of DEF along on the trip or deal with having to fill it when it needs it on a long towing road trip either.  I just want to fill a vehicle when it needs fuel and go.   My 6.2 tows just as well as the 3.0, and is a better fit for me.  If GM wasn't having reliability issues with their current 6.2 I would probably be driving one - but right now it's a big nope, too many problems. 

[JeffKirk]

16 hours ago, Srode1 said:

I was getting ready to start shopping for a replacement for our '15 6.2  and decided to keep it for a while after doing some research on some of the reliability problems with the current drivetrain choices. 

 

The rear drive on the 3.0 engine for the fuel and oil pump along with the potential for ongoing oil consumption problem which GM says is normal isn't making me want that despite great fuel economy.  I've had a diesel before although older LB7, they are nice till they aren't is my experience.  Fuel additives in the Winter, gelling when it's super cold, can be harder to find fuel (good fuel), and special oil now for the 3.0 that is hard to find its all just a bit too much for me to go after right now.   

 

The 6.2 DFM and bearing failures is a non starter till GM get's it resolved and I'm not aware of any solutions yet. 

 

Then there's the 10 speed valve body wear issues that both motors could have - I think I'm better off sticking with what I have for a while longer.  Seems they should have just used the old 5 speed Allision used in the HD trucks which was bullet proof.  

 

I do realize squeaky wheels rise to the top but reliability is king and I'm not willing to throw down 60-80k on a truck that might be a PIA to own when what I have just works (knock on wood). 

This I completely respect and support, but only from a financial point of view.  Vehicles are a depreciating asset and a horrible strain on many households.  That said, there is no such thing as waiting out the current issues that manufacturers are having in their segment space with the EPA push to become compliant with mileage and emissions (let alone engineering to have the most horsepower, comfort, electronics, etc. over their competitors).  We are in an era where the engineering is always pushing, so todays issues that get resolved will be a new set of issues in 5 years.  Since the first vehicle rolled off the assembly line, mechanical failures have been an issue.  Heck, as I sit here, if you visit any forum whether GM, Toyota, Ford, Dodge, etc. and assume you will have the same experience, then might as well plan on never buying another new vehicle.  Forums survive and thrive on doom and gloom.  I have no data to offer, but comfortable stating that for every failure, there are many upon many that didn't.

Edited March 6, 2025 by JeffKirk

[Srode1]

yeah, forums tend to magnify problems but often where there's smoke there's fire too.  When a manufacturer's supply chain can't keep up with repair demands that's a pretty good indication there's a significant issue as is the case with the 10 speed transmission valve body and the 6.2 engine bearing failures. 

 

Platforms will continue to evolve and innovate, I'm choosing to wait until there's a higher level of understanding what the root cause and solution is for these problems before replacing a perfectly serviceable truck that meets all my needs.  It would be nice to have some of the camera features and supercruise etc, but not compelling enough to take the risk on the drive train problems for me right now.  If my truck was totaled in an accident today I would lean towards looking for a similar '15-18  6.2 as a replacement instead of one of these new ones right now. 

Edited March 6, 2025 by Srode1

[Silverado4x4]

On 3/6/2025 at 8:32 AM, Srode1 said:

yeah, forums tend to magnify problems but often where there's smoke there's fire too.  When a manufacturer's supply chain can't keep up with repair demands that's a pretty good indication there's a significant issue as is the case with the 10 speed transmission valve body and the 6.2 engine bearing failures. 

 

Platforms will continue to evolve and innovate, I'm choosing to wait until there's a higher level of understanding what the root cause and solution is for these problems before replacing a perfectly serviceable truck that meets all my needs.  It would be nice to have some of the camera features and supercruise etc, but not compelling enough to take the risk on the drive train problems for me right now.  If my truck was totaled in an accident today I would lean towards looking for a similar '15-18  6.2 as a replacement instead of one of these new ones right now. 

And don't forget I really believe that some people join a forum just to bash a product that probably don't even own the vehicle that the forum supports like people with 1 post that come in and say "The same thing just happened to me" only to be ever heard from again and iam not saying there isn't a problem I think they just join to create more panic.

[Z71RAD88]

1 minute ago, Silverado4x4 said:

And don't forget I really believe that some people join a forum just to bash a product that probably don't even own the vehicle that the forum supports like people with 1 post that come in and say "The same thing just happened to me" only to be ever heard from again and iam not saying there isn't a problem I think they just join to create more panic.

 
100%. I take it with a grain of salt. Still haven’t pulled the trigger yet. Playing the games with dealers currently. With how much inventory they all still have, they’re willing to walk away from deals over a couple hundred bucks. Onward we go. 

[Jus Cruisin]

2 hours ago, Silverado4x4 said:

And don't forget I really believe that some people join a forum just to bash a product that probably don't even own the vehicle that the forum supports like people with 1 post that come in and say "The same thing just happened to me" only to be ever heard from again and iam not saying there isn't a problem I think they just join to create more panic.

True, but when the NHSTA gets involved there's more to it than some keyboard warriors. 

 

[Transient]

I see that you ordered your truck before I was able to post my experience.  Imo, you made the right choice getting the 3.0 Duramax.  I have a 2020 with the 6.2 and lived in San Diego from 2020 to 2023.  Diesel prices were either the same or slightly lower than 91 octane.  It's the mpg that makes the difference.  Iirc, Costco is a Top Tier Fuel Diesel provider.  Otherwise, GM recommends getting their additive whenever you fill up.  The current 3.0 produces more torque than the 6.2.  Both engines also use the same trans.  As such, they're very similar in 1/4 mile times (according to TFL Truck).  Best I ever saw in mpg with the 6.2 is 24.4 mpg.  That was a drive from San Diego to Las Vegas with the cruise set at 78mph.  Like you, I was torn on which engine to get.  I have been very happy with the 6.2, but sad that I didn't get the 3.0 (COVID and empty car lots played a factor in my purchase).  The biggest dis/satisfaction factor is how frequently I have to fill the tank.  If I could do it again I'd get the 3.0, but if I had the 3.0 I'd probably say I'd get the 6.2.

[Jus Cruisin]

14 hours ago, Transient said:

I see that you ordered your truck before I was able to post my experience.  Imo, you made the right choice getting the 3.0 Duramax.  I have a 2020 with the 6.2 and lived in San Diego from 2020 to 2023.  Diesel prices were either the same or slightly lower than 91 octane.  It's the mpg that makes the difference.  Iirc, Costco is a Top Tier Fuel Diesel provider.  Otherwise, GM recommends getting their additive whenever you fill up.  The current 3.0 produces more torque than the 6.2.  Both engines also use the same trans.  As such, they're very similar in 1/4 mile times (according to TFL Truck).  Best I ever saw in mpg with the 6.2 is 24.4 mpg.  That was a drive from San Diego to Las Vegas with the cruise set at 78mph.  Like you, I was torn on which engine to get.  I have been very happy with the 6.2, but sad that I didn't get the 3.0 (COVID and empty car lots played a factor in my purchase).  The biggest dis/satisfaction factor is how frequently I have to fill the tank.  If I could do it again I'd get the 3.0, but if I had the 3.0 I'd probably say I'd get the 6.2.

I'm figuring if I don't like it I'll swap out a little early. I just wish the 6.2l would get warrantied in a timely fashion if they do go south.