3.0L Duramax - who owns or has driven one

steve841 · December 30, 2020

13 minutes ago, Agriont said:

That is good milage. I have a 7.5 x 14 tandem enclosed trailer. Very high V nose.. aluminum trailer. What was the towing weight of your trailer and the payload in your truck?

Maybe 2500lbs total towing .. nothing in the bed.

Here's the trailer on my 6.2

Agriont · December 30, 2020

That is very light.. my trailer empty weighs that. Loaded with my kit, it weighs close to 4.5 to 5k lbs. I also do most of my towing during winter months so it does impact milage.

monteholic · December 30, 2020

officially....

I own one now

Agriont · December 30, 2020

14 minutes ago, monteholic said:

officially....

I own one now

Nice. Z71? I wish the Denali came with that set up, a longer box, greater fuel capacity and max tow with the cameras.

monteholic · December 30, 2020

I wish it had the tow mirrors (it will have them soon enough)

I did get the 3.73 gears

Edited December 30, 2020 by monteholic
spelling

Duramax3oh · January 2, 2021

On 12/29/2020 at 4:10 PM, Agriont said:

30-40% is significant... especially if towing. I'm not so concerned when I'm not towing because the 6.2 is quite frugal under my foot empty. I'm looking at distance between fill ups. I'd like to know real world towing expectations from the 3L per tank towing 5k lbs.

Flat terrain towing a 6K pound 23' airstream going 65mph I make 350 miles on the tank. Going 75 mph is still slightly over 300 mile range.

Unloaded just me and the truck I've made 700 miles on a tank going 60 mph. Faster 75mph area I'm around 600 mile range.

As probably known... 24 gallon tank.

*Edited to add: this is also me knowing the route, distances and availability of stations for filling up. So this gives an idea of my 3.0's kind of "best case".... when driving/towing I pay attention to the DIC's mileage and mpg average to estimate how many gallons I've used on that tank. I rarely go past using 20 gallons and will stop to fill up before approaching empty.

Edited January 2, 2021 by Duramax3oh

Agriont · January 2, 2021

18 minutes ago, Duramax3oh said:

Flat terrain towing a 6K pound 23' airstream going 65mph I make 350 miles on the tank. Going 75 mph is still slightly over 300 mile range.

Unloaded just me and the truck I've made 700 miles on a tank going 60 mph. Faster 75mph area I'm around 600 mile range.

As probably known... 24 gallon tank.

I received this info from an a guy who is doing significant testing with his 3.0 and is going to do the same with a 6.2 he has. I quote...

"I am currently working on a video towing showing the MPG rating at 70mph and 65mph towing a 7x16x7.5' tall enclosed trailer with my truck. Next week I'll be doing the same loop with a 6.2l gas Tahoe to do a comparison. The trailer weight was 4380lbs and as a preview, 13.1mpg was achieved at 70mph and 15.6mpg was at 65mph. Using some simple math I would expect that 60mph would get you around 17.5mpg. I typically tow till about 25% of the tank is remaining and put in about 17 gallons of fuel. This give the truck a fueling range, at 60mph, of about 300 miles or 5hrs of running. In my opinion that is plenty for the balder and stomach to take too.... Those are my expectations for the 3.0 and in a week or two I should have an answer on the 6.2l Gas motor. I'm only going to do one run at 65mph with the trailer but I'm expecting to get around 12mpg."

AlexB · January 2, 2021

35 minutes ago, Agriont said:

I received this info from an a guy who is doing significant testing with his 3.0 and is going to do the same with a 6.2 he has. I quote...

"I am currently working on a video towing showing the MPG rating at 70mph and 65mph towing a 7x16x7.5' tall enclosed trailer with my truck. Next week I'll be doing the same loop with a 6.2l gas Tahoe to do a comparison. The trailer weight was 4380lbs and as a preview, 13.1mpg was achieved at 70mph and 15.6mpg was at 65mph. Using some simple math I would expect that 60mph would get you around 17.5mpg. I typically tow till about 25% of the tank is remaining and put in about 17 gallons of fuel. This give the truck a fueling range, at 60mph, of about 300 miles or 5hrs of running. In my opinion that is plenty for the balder and stomach to take too.... Those are my expectations for the 3.0 and in a week or two I should have an answer on the 6.2l Gas motor. I'm only going to do one run at 65mph with the trailer but I'm expecting to get around 12mpg."

Sounds about right. I'll need to check when pulling my 33' TT. Average was around 17mpg but I'll need to do a proper reset and drive.

calltrex · January 2, 2021

Just ran out of fuel today on my first tank. 901km. I was driving nice for 2 weeks just to see what I could get out of this thing.

May get bit better after engine breaks in

Sent from my SM-G986W using Tapatalk

Sierra Gray-1 · May 19, 2021

I have the GMC version truck ordered March 2020 and delivered October 2020. The first 1000 miles were short trips of less than 2 miles with a couple 15 mile trips and got 20.2 MPG. One week of sub zero temps, truck started without engine block heater. I did let the truck warm at idle for 3-5 minutes before I started to drive.

Two trips one south thru NYC area to DE and averaged 34.5 MPG and a trip north to Maine 32.2 MPG. Both trips traffic was moving 70+ so we stayed with the flow.

It is giving me the mileage I was hoping to get when I bought it.

One dealer visit for engine light. Exhaust cleaner light would come on, but I would shut the truck down at the end of my local trip. I was told to keep the engine running the next time until the warning message goes off.

blckblt · May 19, 2021

My cardinal red 2021 AT4 w/ the 3.0. Offroad steps and bakindustries MX4. Black exhaust outlets. Will be swapping to black GMC emblems, black AT4 emblems and will debadge the chrome sierra on the tailgate next month with I get the front windows tinted.

1100 miles. 22.3 lifetime mpg (idle, city, country roads, highway mix). This has been going up over the past week. I have a trip that I make 3 times a week ~35 miles round trip. 25-31 MPG depending on traffic, lights and regen (got 27 last night and the truck did a regen during). With my previous TB w/ 6.2 the best I got was 21, typically 19ish on the same trip.

Edited May 19, 2021 by blckblt

redwngr · May 19, 2021

Life of vehicle: (except for dealer / gm fill)

- hand calc mileage always a little better than DIC

- all fuel from same pump at same cardlock

- last 5 fills over 620 mile / 1000 km

--- tank capacity is supposed to be 98L, so even the last fill (91L) there should have been about 50 mile cushion

- sierra, crew. 4wd, standard bed, no lift

Filled DEF at bulk pump at 700 miles.

At about 5800 miles the 4th LED on gauge went out (so 1/2). idash bouncing between 45 and 50%.

Book says that for the 3.0L, that means it should be able to hold 2 gallons -- 5000 miles since fill, so 2500 mpg.

(6.6L has larger tank, and is supposed to hold 2.5 gal when the 4th led goes out)


2021 3.0L Duramax
				truck	hand			Odometer	Mpg diff
	odo km	trip km	L	mpg	usmpg	usgal	trip	miles	hand/truck
20-Nov		800?	78.8	23.1				497
30-Nov	1533	733	67.7	24.4	25.5	17.9	455	953	1.1
15-Dec	2133	600	56.7	24.7	24.9	15.0	373	1325	0.2
13-Jan	3022	889	83.4	24.2	25.1	22.0	552	1878	0.9
15-Feb	3844	822	81	23.2	23.9	21.4	511	2389	0.7
8-Mar	4851	1007	88.8	25.7	26.7	23.5	626	3014	1.0
19-Mar	5851	1000	86.3	26.5	27.3	22.8	621	3636	0.8
29-Mar	6850	999	83.1	27.3	28.3	22.0	621	4256	1.0
10-Apr	7930	1080	89.1	28.1	28.5	23.5	671	4927	0.4
29-Apr	9040	1110	91.2	27.8	28.6	24.1	690	5617	0.8
									0.7

						192.1	5120.1

						26.6	overall

Agriont · June 4, 2021

I've heard from a few guys who have purchased the 3L diesel. They say that the truck drinks DEF when towing. Also, the oil changes are beaucoup $$, once the freebs are done. Carry plenty of DEF for long trips.