19-20 mpg possible 6.0 gas?

Chebbyfan · January 30, 2017

I just started a temporary job that I worked at before and it gave me the opportunity to check the mileage on my new 2016 Dually 4x4 6.0 gasser versus my 2008 Duramax Dually 4x4 Duramax. Both trucks weigh 7800 pounds with me and a full fuel tank. The Duramax was an extended cab LTZ,, my new 6.0 is a Crew Cab HIgh Country and both are long box Dually 4x4s models that will never come in a hybrid.LOL , and models that only an idiot would expect great mileage. These are work trucks, like most HD trucks. As I have stated many times I mainly ordered the 6.0 to get the extra 760 pounds of payload more than the same model in a Duramax. Yes, gassers haul more,

diesels pull more, almost double the weight. If the payloads were identical, I would have got another Duramax and I am sure I would have been as happy as a clam, a clam with 11000 less dollars due to Canadian pricing.

My commute round trip is exactly 100 km, I will convert to miles per US gal . My new truck uses 17.6 litres per 100 km, the 08 Duramax used 15.8 litres per 100 km. This is Highway with several traffic lights and a few sections of slower driving but mostly 60 miles per hour with a few mild grades. New 6 litre gas is getting 13.4 miles per US gal on this commute. 08 Duramax got 14.9 miles per US gal. I was saving a whopping 1.5 litres a day with the Duramax and the current price of 1.14 per litre that is 1.71 CAD a day. I would have to drive that commute every single day for 17 years to break even. WOW! I have to say I realize the new Duramaxes are probably better on fuel but right now I am so happy the GMC engineers made the payload so much larger with a 6.0 gasser, saved me a ton of money and the 6.0 is fun to drive, the 4.10 gears make it feel as nifty as the Duramax with 3.73s and if I would have kept pulling a heavy Fifth wheel like the 33 foot Montana I had for 10 years, I would have needed another Duramax, and pulling heavy the Duramax might get double the mileage of a 6.0 gasser pulling the same weight. Bottom line, if you need to haul heavy, go gas, if you need to tow heavy go diesel, but don't expect great mileage from these HD trucks. Stick with a little 1500 if gas mileage is your main priority.

I understand. I wasn't complaining about the mileage these trucks get. I now have had two 6.0 gassers, and neither one has great mileage. I bought mine because a couple times a year I pull our enclosed trailer and quads 3-5 hours away (depending which direction we go) and camp for a weekend ride. I didn't want to overwork a 1/2 ton, and I didn't want the 4 cylinders on and 4 off that the 1/2 tons have on them. I was questioning my friends claim that his early 15 HD will get 19-20 mpg and wondered if there could be any difference in our trucks other than physical. Mine and his are the same thing.

Rvduck · January 30, 2017

I understand. I wasn't complaining about the mileage these trucks get. I now have had two 6.0 gassers, and neither one has great mileage. I bought mine because a couple times a year I pull our enclosed trailer and quads 3-5 hours away (depending which direction we go) and camp for a weekend ride. I didn't want to overwork a 1/2 ton, and I didn't want the 4 cylinders on and 4 off that the 1/2 tons have on them. I was questioning my friends claim that his early 15 HD will get 19-20 mpg and wondered if there could be any difference in our trucks other than physical. Mine and his are the same thing.

Sorry if my post sounded like I was dissing your topic, I think a regular cab 4x2 with a 6.0 on a flat road with a tail wind might be able to get close to 20 miles per US gal. I was responding more to the folks that trash the 6.0 for the power it makes and the fuel it burns. Many of these people drive a 1500 with the 5.3 or 6.2 and it is not a fair comparison. Thanks for your post.

azsheepdog · January 30, 2017

From Phoenix to Flagstaff and back..average was 15.2 best was 19.5

ewbldavis · January 30, 2017

No way. I average 16 in my 5.3L 1500/3.42 in winter and barely break 18-19 MPG in summer.

I do push 19-20 when driving from campground, since it is all country 2-lane going 55-60.

f8l vnm · January 30, 2017

here is to hoping that GM gives us a real HD gas motor not this anemic 6.0 and no way in hell your getting 19-20 even in a regular cab.

ive had 3 buddies with 6.0 motors and none of them touch 15

i82much · January 30, 2017

here is to hoping that GM gives us a real HD gas motor not this anemic 6.0 and no way in hell your getting 19-20 even in a regular cab.

ive had 3 buddies with 6.0 motors and none of them touch 15

My definition of a real engine is one that lasts longer than I will. My 6.0 fits the bill perfectly.

Chebbyfan · January 31, 2017

The one and only complaint you'll ever hear from me about my truck is, I wish it had more "performance." I know it's not a race truck, and I know it was designed for towing and work ability, but I want more seat of the pants performance. I had an old 78 3/4 ton chevy back in the day with a 454, and I admit it was worked over with a cam, intake, carb, etc and it would flat run, pull, and cut cookies like no other. Why can't I have just a little of that performance out of this truck?

Dirtbiker · January 31, 2017

The one and only complaint you'll ever hear from me about my truck is, I wish it had more "performance." I know it's not a race truck, and I know it was designed for towing and work ability, but I want more seat of the pants performance. I had an old 78 3/4 ton chevy back in the day with a 454, and I admit it was worked over with a cam, intake, carb, etc and it would flat run, pull, and cut cookies like no other. Why can't I have just a little of that performance out of this truck?

I had that in my 2006. It was called an 8.1 litre. They need to bring it back. And it was pretty much the same mileage as this 6.0.

i82much · January 31, 2017

The one and only complaint you'll ever hear from me about my truck is, I wish it had more "performance." I know it's not a race truck, and I know it was designed for towing and work ability, but I want more seat of the pants performance. I had an old 78 3/4 ton chevy back in the day with a 454, and I admit it was worked over with a cam, intake, carb, etc and it would flat run, pull, and cut cookies like no other. Why can't I have just a little of that performance out of this truck?

I have a 72 K10 longbed converted to a mild 396. My 6.0 would smoke it easily. I love the old truck, and it runs great, but it will not keep up with my 2016.

Nathan79 · January 31, 2017

here is to hoping that GM gives us a real HD gas motor not this anemic 6.0 and no way in hell your getting 19-20 even in a regular cab.

ive had 3 buddies with 6.0 motors and none of them touch 15

The 6.0 is a great motor and is not a epic in any way. One of the most long lasting and most reliable motors out there and pulls stronger than the other manufacturers despite their so called higher HP ratings. But that is why it is the entire drivetrain for the 6.0 that really shines.

ewbldavis · January 31, 2017

Let's be honest here too - you don't buy a full-size truck, certainly not a 2500/3500, for fuel mileage.

Also being honest - I'll be swapping my 1500 for a gas 2500 at lease end. Sure - I'll see a drop in MPG and kind of miss the difference, but the performance improvement will be a better offset.

i82much · January 31, 2017

Let's be honest here too - you don't buy a full-size truck, certainly not a 2500/3500, for fuel mileage.

Also being honest - I'll be swapping my 1500 for a gas 2500 at lease end. Sure - I'll see a drop in MPG and kind of miss the difference, but the performance improvement will be a better offset.

If you are buying a truck for the long haul, I think it is important to consider maintenance costs as well as fuel economy. Let's say a 1/2 ton saves you $500 a year on gas. Well, sure, but do the brakes last longer on the 3/4 or one ton? How about the shocks, axle bearings, the transmission, that sort of thing. From one perspective, you could work a 1/2 ton hard or give a 3/4 ton an easy life. Which one really costs more in the long run? Probably the 3/4 ton, sure, but maybe not as much as you would think if you considered only fuel economy and up-front cost.

Also, I was able to find some 3/4 ton crew cab 2016 WT's on the lot. I don't think dealers order many 1/2 ton crews in the WT trim. So my feeling was, why spend 35k on an LT 1500 when I can spend 35k on a WT 2500? I'd rather have the stronger truck. I like vinyl floors, and transfer case shifters are supposed to be on the floor too!

Cowpie · February 1, 2017

here is to hoping that GM gives us a real HD gas motor not this anemic 6.0 and no way in hell your getting 19-20 even in a regular cab.

ive had 3 buddies with 6.0 motors and none of them touch 15

Well, we just don't have any real data to show how much your buddies driving style affects things. And considering that driving style accounts for over 1/3 of mpg average, it can make quite a difference. My 2015 2500 DC Z71 LT has averaged a little over 13 mpg, but that is everything.... gravel roads daily, off road on the farm/ranch, hauling a ton of oil drums, parts, material, towing, snowplowing (not as much of that this year), in town and highway... all combined. And on road trips over 500 miles, it has pulled off a respectable 17-18 mpg. Now true, I don't try to drive it like I stole it or trying to get poll position at Daytona, but I also do not drive 55 everywhere either. And I use manual mode on the trans probably 80% of the time and select the shifts or gear I want to run in. 19-20 mpg would be a stretch, but in the right hands, the 2500 6.0L can sure come close.

Anemic? The 6.0L gasser? Are you kidding? It has pulled my semi truck up the driveway incline in snowy/icy weather because I couldn't get enough traction with the big truck. It doesn't complain a bit and acts like nothing it back there with 5 -55 gallon oil drums riding in the bed (over 1 ton). And I only pull equipment trailer or dump trailer, and have never once felt I needed anything more for power.

Edited February 1, 2017 by Cowpie

X25 · February 1, 2017

Our old "Imperial" gallon is larger than the US gallon, then we went to the L/100 km nonsense. I'll check my "mileage and convert it to "our" MPG. It'll be interesting to see what I can get w/ my truck.

I don't recall off the top of my head, what I got w/ my '94 K1500 (350/AT/3.42), but it wasn't all that bad compared to my '88 S15 4x4 w/ the 4.3L in it.

That L/100km 'nonsense' is a linear scale unit, and what we should've got as well. Instead, we have to deal with the grossly misleading MPG, where 1 MPG difference might mean a whopping 20% more fuel during towing.

revrnd · February 1, 2017

That L/100km 'nonsense' is a linear scale unit, and what we should've got as well. Instead, we have to deal with the grossly misleading MPG, where 1 MPG difference might mean a whopping 20% more fuel during towing.

Everyone in Canada used MPG before our "beloved" know it all gov't of the day intro'd the metric system to us whether we wanted it or not.