Which engine - 5.3, 6.2 or 3.0?

[Bikerjon]

10 hours ago, Z71RAD88 said:

I'm moving forward with a new truck purchase in the next few weeks and struggling to decide which engine to go with. I live in CA and don't tow. Typically drive 20,000 per year. My typical commute is 35 miles each way with 90% country roads at 55 mph and freeway at 65 mph, a combo of the two. I do get up the mountains frequently so the extra torque from the 6.2 and 3.0 appease me. I do understand having the turbo will be helpful at elevation compare to a NA engine. 

 

I was initially all set on the 6.2 but with the recent notice from NHTSA, It's got me thinking twice. 

 

Never owned a diesel and don't feel overly confident I can feed it the proper/required diesel living in California. 

 

What would you all go with? Trim level wise going RST or LTZ. Deals seem to be better on the LTZ with the 3.0. 

I got a Trail Boss with a 6.2 in December. Holy sh*t is this thing fast compared to my other Silverado's with the 5.3. Never had any problems with the 5.3s. As for any problems with the 6.2 engine there are hundreds of thousands of them out there running just fine and making a lot of power. If I have any problems with my engine GM is going to fix it. That's what a warranty is for. As far as gas mileage forget it. I ride a Harley and drive a big 4X4 so I don't worry about gas mileage, however living in Cali this may be more of a concern to you. If you are asking my opinion I would go with a gas powered V8. 5.3 or even better a 6.2.

[Jus Cruisin]

I've had a 6.2l for a little over 2 years. I have the GM performance exhaust on it and love the sound. Highway mpg is 22ish. Around town, it is 16ish. Premium gas is all that I use. 

 

All though I'm happy with the 6.2l, I'm thinking I'll go 3.0l next. Diesel is cheaper than premium. I'll give up the V8 growl though. 

[Z71RAD88]

Thanks for the replies folks. Keep’em coming. 

[JeffKirk]

I posted this on another engine debate thread, but speaks to your question with the exception that I have never owned a diesel.  Don't get caught up in some of the mileage claims...one on this thread is a 7.2 mile sampling, so totally irrelevant.  My 2018 with the 5.3 averaged 18.9 over a 6000 mile time period of mixed city and highway use.  My 6.2 is currently logging 18.1 over a 3500 time period of the same use.

 

I know we beat this to death and opinions are all over the board, but here is my experience and thoughts.

• Bought a 2018 GMC Sierra SLT new with the 5.3 and 8 speed transmission.  Owned that over 6 years and 65K miles using it as a typical homeowner would.  I do tow a 6000 pound tri-toon boat which the 5.3 handled well.
• Traded in my 2018 for a 2024 GMC Sierra Denali with the 6.2 and 10 speed transmission.  The difference in power and all around drivability is obvious and I do think the 10 speed contributes to that.  Pulling my boat is a different experience now in terms of power.  This is where you really notice the increased torque and my pulling mileage improved by 1.5 mpg (calculated running the same 8 hour roundtrip we do every year).  I do run 93 octane gas even though this is debated up and down, I don't care for one minute about spending the extra dollars at the pump.  I'm not rich, but capable of owning this truck and putting 93 in it.  
• Bottom line, I would never look back at the 5.3 after owning the 6.2, to me it would now be a deal breaker.  That said, no disrespect for the 5.3 and I had a great experience with mine.  No mechanical failures and only routine maintenance in 6 years of ownership.  I do hope the 6.2 gives me the same experience, but time will tell.

One happy 6.2 owner here!

 

Edited March 4, 2025 by JeffKirk

[newdude]

22 hours ago, PunchT37 said:

My ‘25 LT 2wd 5.3 with 3.42 gears has done this, at least at times. 
 

 

 

22 hours ago, Z71RAD88 said:

 

Wow. Impressive. Thanks for sharing. 

 

 

Is it though?  I can reset my trip meter and drive 7 miles and get the same result.  That's not an accurate measurement of MPG, what it can achieve in a 7 mile stretch.  

 

 

 

[JeffKirk]

2 minutes ago, newdude said:

 

 

 

Is it though?  I can reset my trip meter and drive 7 miles and get the same result.  That's not an accurate measurement of MPG, what it can achieve in a 7 mile stretch.  

 

 

 

Exactly my thoughts.  I have a very long downhill stretch where I live and could post a mpg photo that would make you run and buy a 6.2...lol

[newdude]

2.7 Turbomax, 3.0 Duramax and 5.3.  Skip the 6.2.  

 

Turbomax and the Duramax have the best factory powertrain warranty, 5yr/100k miles.  The only downfall is the Turbomax can be option limited so if you wanted buckets, gotta go with one of the other engines.  As for MPG with the Turbomax, I've got 3 years on mine (2022.5 HO before they called it Turbomax) and I've averaged the life of the truck almost 4mpg more than my old 2018 5.3 6 speed.  Currently in 32,000mi, lifetime MPG is 19.3mpg, my 5.3 when I traded it was 15.7mpg lifetime in 48,000mi.  

 

Duramax is the MPG king for sure.  There is added costs (diesel does run closer to 91/93 prices but again, better MPG, oil changes are a bit more, DEF).  You could easily get 25mpg or more per tank out of the 3.0.    

 

5.3 with the 10 speed makes the 5.3 a way better platform that it used to be with the 6 speed.  It was better with the 8, but the 10 makes it more enjoyable.  

[Z71RAD88]

8 minutes ago, newdude said:

2.7 Turbomax, 3.0 Duramax and 5.3.  Skip the 6.2.  

 

Turbomax and the Duramax have the best factory powertrain warranty, 5yr/100k miles.  The only downfall is the Turbomax can be option limited so if you wanted buckets, gotta go with one of the other engines.  As for MPG with the Turbomax, I've got 3 years on mine (2022.5 HO before they called it Turbomax) and I've averaged the life of the truck almost 4mpg more than my old 2018 5.3 6 speed.  Currently in 32,000mi, lifetime MPG is 19.3mpg, my 5.3 when I traded it was 15.7mpg lifetime in 48,000mi.  

 

Duramax is the MPG king for sure.  There is added costs (diesel does run closer to 91/93 prices but again, better MPG, oil changes are a bit more, DEF).  You could easily get 25mpg or more per tank out of the 3.0.    

 

5.3 with the 10 speed makes the 5.3 a way better platform that it used to be with the 6 speed.  It was better with the 8, but the 10 makes it more enjoyable.  

 

Ya, I'm going buckets. Over the past few days really leaning towards the 5.3. It best suites my needs a vast majority of the time. 

[PunchT37]

1 hour ago, newdude said:

 

 

 

Is it though?  I can reset my trip meter and drive 7 miles and get the same result.  That's not an accurate measurement of MPG, what it can achieve in a 7 mile stretch.  

 

 

 

This should be a little better. By the way, no long hills here. 

[newdude]

1 hour ago, PunchT37 said:

This should be a little better. By the way, no long hills here. 

 

 

41mi.  Doesn't count.  Show us what you get on a tank or current lifetime MPG, that counts.  

[PunchT37]

16 minutes ago, newdude said:

 

 

41mi.  Doesn't count.  Show us what you get on a tank or current lifetime MPG, that counts.  

You are correct but, I did say "at times, at least" in the 1`st post. What does any engine get it`s whole life? Lots of factors involved. I know my 2000 LM7 with 3.73 gears won`t come close to this T1 truck with the L84.

 

I`m not trying to deceive anyone into believing a heavy truck with a v8 gets 25 mpg all day, every day.

Edited March 4, 2025 by PunchT37

[Z71RAD88]

3 hours ago, newdude said:

2.7 Turbomax, 3.0 Duramax and 5.3.  Skip the 6.2.  

 

Turbomax and the Duramax have the best factory powertrain warranty, 5yr/100k miles.  The only downfall is the Turbomax can be option limited so if you wanted buckets, gotta go with one of the other engines.  As for MPG with the Turbomax, I've got 3 years on mine (2022.5 HO before they called it Turbomax) and I've averaged the life of the truck almost 4mpg more than my old 2018 5.3 6 speed.  Currently in 32,000mi, lifetime MPG is 19.3mpg, my 5.3 when I traded it was 15.7mpg lifetime in 48,000mi.  

 

Duramax is the MPG king for sure.  There is added costs (diesel does run closer to 91/93 prices but again, better MPG, oil changes are a bit more, DEF).  You could easily get 25mpg or more per tank out of the 3.0.    

 

5.3 with the 10 speed makes the 5.3 a way better platform that it used to be with the 6 speed.  It was better with the 8, but the 10 makes it more enjoyable.  

 

3 hours ago, newdude said:

2.7 Turbomax, 3.0 Duramax and 5.3.  Skip the 6.2.  

 

Turbomax and the Duramax have the best factory powertrain warranty, 5yr/100k miles.  The only downfall is the Turbomax can be option limited so if you wanted buckets, gotta go with one of the other engines.  As for MPG with the Turbomax, I've got 3 years on mine (2022.5 HO before they called it Turbomax) and I've averaged the life of the truck almost 4mpg more than my old 2018 5.3 6 speed.  Currently in 32,000mi, lifetime MPG is 19.3mpg, my 5.3 when I traded it was 15.7mpg lifetime in 48,000mi.  

 

Duramax is the MPG king for sure.  There is added costs (diesel does run closer to 91/93 prices but again, better MPG, oil changes are a bit more, DEF).  You could easily get 25mpg or more per tank out of the 3.0.    

 

5.3 with the 10 speed makes the 5.3 a way better platform that it used to be with the 6 speed.  It was better with the 8, but the 10 makes it more enjoyable.  

I agree with your fuel selection on the 6.2, if I were to go with it I’d run it with 91 since that’s the highest we even have in CA. I own zero equipment to tow so I don’t have that factor in my engine choice. I’ve driven both and you can for sure tell the difference but I’d only be getting the 6.2 for bragging right and less downshifting going uphill, faster acceleration, etc. 

[JeffKirk]

1 hour ago, Z71RAD88 said:

 

I agree with your fuel selection on the 6.2, if I were to go with it I’d run it with 91 since that’s the highest we even have in CA. I own zero equipment to tow so I don’t have that factor in my engine choice. I’ve driven both and you can for sure tell the difference but I’d only be getting the 6.2 for bragging right and less downshifting going uphill, faster acceleration, etc. 

I completely understand where your are coming from, the 5.3 served me well for 6 years and was reliable.  Congrats in advance of your new to be truck, you will love it!

[Z71RAD88]

4 hours ago, JeffKirk said:

I completely understand where your are coming from, the 5.3 served me well for 6 years and was reliable.  Congrats in advance of your new to be truck, you will love it!

Thank you! I am really excited. Been almost 10 years since my last new vehicle. Looking forward to the upgraded features of a 2025 vehicle. 

[redwngr]

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.  

 

 

 

Edited March 5, 2025 by redwngr