6.2L vs 3.0 Diesel, considering upgrading from my '18 6.2L

Nitrousbird · April 5, 2021

It seems that Carvana wants to offer more for my 2.5 year old '18 Sierra SLT than I paid for it new (other than tax). It is making me consider an upgrade to a Denali Ultimate or a loaded up AT4.

I tow a 5000ish lb boat. Most of my towing is a 2 mile drive maxing at 45MPH, where the 2.7L 4 banger would suffice. But about twice a year we do a 700 mile round trip going through the Kentucky and Tennessee mountains. On those trips, we are loaded with gear and around 7000lbs total with gear/passengers. I will also likely upgrade to a bit larger boat in the next couple of years, expecting that number to climb to 8000lbs. I may also begin racing/towing my car, but that will end up being lighter than the boat.

I'm happy with the 6.2L / 8-speed tranny combo I have today. I know I will be happy with the 6.2L / 10-speed combo. Will I be happy with the diesel? I don't put a lot of miles on the truck (10,500 in 2.5 years). The diesels are more plentiful and significantly cheaper. I can get a crew AT4 with Tech, Driver Alert II, Sunroof, AT4 value, tow mirrors, with the diesel for $54,500 out the door (plus tax). About $3500ish more for a Denali Ultimate.

Thoughts on one engine vs the other? I was planning on keeping my current truck 5-10 years and if it wasn't for today's stupid high resale, I wouldn't be considering getting rid of it as it has been a great.

ullose272 · April 5, 2021

8 minutes ago, Nitrousbird said:

It seems that Carvana wants to offer more for my 2.5 year old '18 Sierra SLT than I paid for it new (other than tax). It is making me consider an upgrade to a Denali Ultimate or a loaded up AT4.

I tow a 5000ish lb boat. Most of my towing is a 2 mile drive maxing at 45MPH, where the 2.7L 4 banger would suffice. But about twice a year we do a 700 mile round trip going through the Kentucky and Tennessee mountains. On those trips, we are loaded with gear and around 7000lbs total with gear/passengers. I will also likely upgrade to a bit larger boat in the next couple of years, expecting that number to climb to 8000lbs. I may also begin racing/towing my car, but that will end up being lighter than the boat.

I'm happy with the 6.2L / 8-speed tranny combo I have today. I know I will be happy with the 6.2L / 10-speed combo. Will I be happy with the diesel? I don't put a lot of miles on the truck (10,500 in 2.5 years). The diesels are more plentiful and significantly cheaper. I can get a crew AT4 with Tech, Driver Alert II, Sunroof, AT4 value, tow mirrors, with the diesel for $54,500 out the door (plus tax). About $3500ish more for a Denali Ultimate.

Thoughts on one engine vs the other? I was planning on keeping my current truck 5-10 years and if it wasn't for today's stupid high resale, I wouldn't be considering getting rid of it as it has been a great.

If you enjoy the higher rpm pull of the 6.2 then i would stick with it, if you want something that has some good bottom end grunt for towing gets good mileage then the 3.0 might be good? You will lose some passing power with the 3.0, but thats really the only time i am disappointed in the 3.0

OnTheReel · April 5, 2021

I don’t think you drive enough for the diesel. I wouldn’t want to frequently short trip or let a modern diesel sit around too much. Just my opinion.

btj_z71 · April 5, 2021

1 hour ago, Nitrousbird said:

It seems that Carvana wants to offer more for my 2.5 year old '18 Sierra SLT than I paid for it new (other than tax). It is making me consider an upgrade to a Denali Ultimate or a loaded up AT4.

I tow a 5000ish lb boat. Most of my towing is a 2 mile drive maxing at 45MPH, where the 2.7L 4 banger would suffice. But about twice a year we do a 700 mile round trip going through the Kentucky and Tennessee mountains. On those trips, we are loaded with gear and around 7000lbs total with gear/passengers. I will also likely upgrade to a bit larger boat in the next couple of years, expecting that number to climb to 8000lbs. I may also begin racing/towing my car, but that will end up being lighter than the boat.

I'm happy with the 6.2L / 8-speed tranny combo I have today. I know I will be happy with the 6.2L / 10-speed combo. Will I be happy with the diesel? I don't put a lot of miles on the truck (10,500 in 2.5 years). The diesels are more plentiful and significantly cheaper. I can get a crew AT4 with Tech, Driver Alert II, Sunroof, AT4 value, tow mirrors, with the diesel for $54,500 out the door (plus tax). About $3500ish more for a Denali Ultimate.

Thoughts on one engine vs the other? I was planning on keeping my current truck 5-10 years and if it wasn't for today's stupid high resale, I wouldn't be considering getting rid of it as it has been a great.

I'd say go for the 3.0L Duramax. I have it in my 2020, coming from a 2014 with the 5.3L, and I love it.

I certainly miss the HP like others will certainly attest to, but it is a very impressive engine paired with the 10-speed.

I tow and haul occasionally, and was considering the 6.2L but the MPG had me worried since, once the pandemic is over, I'll be back to driving 30k miles a year.

I've only towed near or above max tow rating once with each truck, and that was towing a skid steer on a heavy duty dual axel trailer. The 3.0L towed better, but keep in mind I'm comparing a 2014 5.3L to a 2020 3.0L. Differences in suspension, frame, drivetrain, etc., all add up to a better overall experience in the 2020. However, the torque (especially low-end) of the 3.0L Duramax was very evident.

Nitrousbird · April 5, 2021

Sounds like it will tow fine but I should probably drive one at a local dealer to make sure I like how the diesel drives on its own.

the wanderer · April 5, 2021

Diesel's are not built for 2 mile runs. I would get the 6.2, you don't drive enough to worry about gas savings considering you just need 1 out of warranty expense on the diesel to kiss your savings permanently goodbye.

And the 2.7 isn't a bad idea either, you only do it twice, and in the mountains it should perform well due to turbo and lots of low end torque.

Edited April 5, 2021 by the wanderer

Nitrousbird · April 5, 2021

6 hours ago, the wanderer said:

Diesel's are not built for 2 mile runs. I would get the 6.2, you don't drive enough to worry about gas savings considering you just need 1 out of warranty expense on the diesel to kiss your savings permanently goodbye.

And the 2.7 isn't a bad idea either, you only do it twice, and in the mountains it should perform well due to turbo and lots of low end torque.

2.7L is only offered in the lower spec trucks. I'm also not looking for a major powerplant downgrade - I also won't consider the 5.3L.

The reason I'm considering the diesel is the $1500 lower cost compared to the 6.2L and much easier to come by. Other than the local tows for boating, all of my other driving does get the oil fully to temp, but the truck will sit for 1-2 weeks at a time, as I'll take my car out in nice weather and I've been putting miles on the wife's for family trips as well.

Edited April 6, 2021 by Nitrousbird

redwngr · April 5, 2021

You won't like the sound of the 3.0L compared to the C6. Turbo I6 doesn't rumble like a V8 .2

Imho, the 3.0L would be fine for the job described.

blckblt · April 6, 2021

I have the 6.2 w/ the 10 speed. 13k miles. Mixed driving of highway, country roads, in town driving. Some idle for warm up in the winter and cool down in the summer. my life time mpg is 14.8. I can get 18-22 when not in town. highway is more around 15-18 as I am usually around 80 mph.

I drove a 3.0 last November 16.4 mile test drive of mix of in town and country roads and averaged 24.8. This was in a brand new chevy LTZ.

while not quite as snappy as my 6.2 having all of the tourqe available at 1500~ RPM is very nice. I thought the power was more then acceptable. I didn't get to drive on the highway...

For the the added MPG etc I have an AT4 with the 3.0 on order (if it ever shows up). I will give up a little bit of stop light power.

Edited April 6, 2021 by blckblt

Duramax3oh · April 6, 2021

I think the 6.2L in the Denali or AT4 would suit you best and in the long run you’d be happier with that.

mjonesjr84 · April 6, 2021

17 hours ago, the wanderer said:

Diesel's are not built for 2 mile runs. I would get the 6.2, you don't drive enough to worry about gas savings considering you just need 1 out of warranty expense on the diesel to kiss your savings permanently goodbye.

You do realize that the 3.0 has a 5 year 100,000 mile warranty right?

The only complaint you will have with the 3.0 vs the 6.2 is the passing power. The torque numbers are the same, however the 3.0 has a flat torque curve that peaks at 1,500 RPM. I love my 3.0 and would buy one again.

Logan Lanfear · April 6, 2021

Sounds to me like you might be leaning towards the 3.0 slightly. Price wise, I would say go for it. Considering you only really tow a couple times a year (any significant kind of trip) any power loss would not be very noticeable. Personally id recommend the 5.3 but you're against that so ill ignore it.

Go for the diesel and try something new. There's no reason not to at least test drive one. Ask the dealer if they have one you can take for 24 or 48 hours. Hook your boat to it and pull it around for giggles. It may at least give you some insight on the power levels and differences between the engines.

the wanderer · April 6, 2021

2 hours ago, mjonesjr84 said:

You do realize that the 3.0 has a 5 year 100,000 mile warranty right?

He is also talking about keeping his truck(s) 5 to 10 years. If he gets a diesel and drives it 95% of the time for a 2 mile trip, he is guaranteed to have issues.

Transient · April 6, 2021

Whatever you do, get the 10-speed. /s

If you like the 2.7T you can get whatever truck has it and add the AT4 lift and suspension in the deal. The dealership can install it, too. The kit is a GM Accessory.

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MG386 · April 6, 2021

I have a 6.2 10speed AT4 and tow a 7k boat a lot through the mountains 7%grade 1:40 each way to the lake. The truck does great. It will rev up a bit if your trying to go fast 65-70, but it's been great.

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