2015 2500 duramax fuel mileage

[Tar]

I am thinking about upgrading to a 2015 2500hd duramax to pull my 34' 9600# fifth wheel from my current 2500 gas truck and wondering what fuel mileage to expect pulling in mostly flat land travel with some small hills?

[Toolguy5]

2015 3500 Denali I get 12 to 13 miles per gallon towing. Only had it on 1 trip so far. But the trip was From Cleveland to Gettysburg. Gettysburg to Washington DC. Washington DC to Mount Airy, North Carolina. Mount Airy to Severville, Tennessee. Severville back home to Cleveland.
This was much better then my 2006 2500 Siverado were I averaged 10 miles per gallon towing.

[tabraha]

whiterose wrote:
Now have a 2015 Denali with Duramax and a 15,000# Montana on order. Hoping for 12 mpg, but reading some of the messages unlikely to achieve this. Unloaded and travelling at 65 (220 mile trip) I achieved 21 mpg and at 70 I achieved 20 mpg (450 mile trip). Had a surprise last week when I returned 13 mpg at a steady 55 mph over 40 miles and then on the return trip 23 mpg. Discovered this was down to the raw fuel being dumped into the exhaust as part of the emission equipment.
So come April I will have experience with the big Montana. I will search for the 'Truck Haul' speed that allows me to use all of the transmission ratios.

Yep you will have the occasional regen and you will also notice going through DEF a bit quicker when towing for extended times. All in all not real major issues considering the ease of which it will motor on down the road. So far your mpg sounds right in line and I'd agree you probably won't quite make a 12mpg average. I'd lean more towards 10 with that kind of weight. You will still have far greater range than with the old setup and probably be ready to get out and stretch your legs by the time you need fuel. 🙂

[N-Trouble]

whiterose wrote:
Had a surprise last week when I returned 13 mpg at a steady 55 mph over 40 miles and then on the return trip 23 mpg. Discovered this was down to the raw fuel being dumped into the exhaust as part of the emission equipment.

Its called "regen" of the DPF (diesel particulate filter) and diesels have been doing this since 2007.

[whiterose]

Traded in a 2013 Silverado 1500 with 6.2L engine. Towing a Montana 10,000# 5th wheel I averaged 8.5 mpg, which with a 26 gallon tank resulted in many fuel stops. This six speed transmission in 'Truck Haul' mode would not engage sixth gear under 60 mph, so I typically towed at 62. I also discovered fuel economy when pulling the 5th wheel was better than pulling a smaller 8000# regular RV trailer, put that down to better airflow.
Now have a 2015 Denali with Duramax and a 15,000# Montana on order. Hoping for 12 mpg, but reading some of the messages unlikely to achieve this. Unloaded and travelling at 65 (220 mile trip) I achieved 21 mpg and at 70 I achieved 20 mpg (450 mile trip). Had a surprise last week when I returned 13 mpg at a steady 55 mph over 40 miles and then on the return trip 23 mpg. Discovered this was down to the raw fuel being dumped into the exhaust as part of the emission equipment.
So come April I will have experience with the big Montana. I will search for the 'Truck Haul' speed that allows me to use all of the transmission ratios.

[LKHA]

:B

Rambino wrote:
We purchased our truck as a tool to tow our "Recreational" vehicle to different places. If we were concerned about fuel economy, and wasted time crunching numbers as to options, weights, etc. to get the "best" fuel efficient vehicle, then owning an RV would not be as enjoyable. We may not even have gotten into RVing. Fuel, whether diesel or gasoline, is a necessary evil of owning an RV. We purchased the truck that gives us what we need, with the options we wanted. We don't carry a calculator to determine MPG. We don't worry about what speed is most fuel efficient. When the tank gets low on fuel we stop and fill up and pay. We are by no means wealthy. But we know that the price of fuel is small compared to what was spent to purchase the RV and the tool to tow it. We look forward to the next destination, not how much fuel it takes to get there. JOHO

[bucky]

Stick to the topic party pooper :).

[Rambino]

We purchased our truck as a tool to tow our "Recreational" vehicle to different places. If we were concerned about fuel economy, and wasted time crunching numbers as to options, weights, etc. to get the "best" fuel efficient vehicle, then owning an RV would not be as enjoyable. We may not even have gotten into RVing. Fuel, whether diesel or gasoline, is a necessary evil of owning an RV. We purchased the truck that gives us what we need, with the options we wanted. We don't carry a calculator to determine MPG. We don't worry about what speed is most fuel efficient. When the tank gets low on fuel we stop and fill up and pay. We are by no means wealthy. But we know that the price of fuel is small compared to what was spent to purchase the RV and the tool to tow it. We look forward to the next destination, not how much fuel it takes to get there. JOHO

[bucky]

Turn off the cruise control. It is blindly trying to maintain a speed with no thought to mpg and will cost you. Watch your EGT gage if you have one, you'll see what I and many others have experienced. Higher temps means more fuel is being burned. If you don't have gages shame on you.

[tabraha]

Tar-

Just did 1600 miles from SC to Miami and got 11mpg on my 2015. That was with a 39' 5'er weighing a little over 13k. It also included a ton of nasty I-95 traffic. The truck isn't even broke in good yet at 5,000 miles so mpg should go up a tick down the road. Also that was on 35" tires. My 2013 2500 on stock tires was typically 12-13 with the same load.

[RVER]

It really does matter if you drive 4x4 or 4x2. 4x4 are heavier, also wind, terrain etc. My truck is a 4x4 and best milage is 23 on flat land highway. Best pulling my heavy fifth wheel is 13.2 on same flat road. I love this truck but would like a new one so I feel safer going long distance cross country but do not want to have to put in diesel additive which some stations run out of etc. Hope they find another way to take care of the problem.

[laknox]

FWIW, the best mileage I ever got with my '02 D'max was right at 23 mpg on a trip up to Cortez CO in '14. I had a 14 cu ft chest freezer in the back, tucked up against the back of the cab. I started off at 65 mph and DW said I was driving too slow (a change!) so I ramped it up to 75. Temps through N AZ and SW CO were in the high 20's to low 40's. I consistently saw 21-23 mpg the whole trip. Surprised hell out of me and I can only attribute it to having the freezer in the bed and how it affected the aerodynamics. My previous best mpg was right at 22, down near Patagonia, when we were simply putzing around and touring some of the S AZ wineries. 🙂

Lyle

[Landroamer1]

Mine gets 16-18.5 empty and 9-10 towing 11k.

[Pipeman]

Mine is a 2011 dually, LB, crew cab,4x4. My 5er is 35 ft. Pulling the 5th I get anywhere between 9 to 13 mpg, sometimes a bit more. Depends on terrain, wind, etc. I have a 50 gal aux. fuel tank in the bed. When we boondock I fill the 5er's fresh water up and also a portable 50 gal water tank and get the same mileage -/+. It's my 2nd Duramax.

[knshook]

Hi Tar----In 2013, we went from a Chevy 2500 8.1 liter gas/Allison Tranny combo to a 2013 Duramax SRW 2500 HD 2x4. Per the DIC, I have seen 11.5-14 mpg. towing. 19 to 22 mpg no/load on the freeway. I tow a 33ft. 11k fifth wheel. The torque and power of the diesel plus the ability to manual shift while using the exhaust brake in hilly/mountain conditions, make for a greater towing experience. Took a 10k mile trip last year and with pre-planning, RV parks and fuel stops were not a problem. A good day to you--happy travels. Ken