Upgrade to a diesel or not?

[ObiRich]

I have a question or two. I've been toying with the idea of getting a newer truck to pull our 5er with. My current one is a 2009 Sliverado 1 ton, but it's a gasser. Although it does an adequate job pulling it, the fuel consumption is pretty high (get about 7-8mpg), and the engine revs pretty high when going up grades unless I really let the speed bleed off. We live in the mountains, so we do have a fair number of long grades. So I've been thinking about getting a diesel. But that's not the only reason I'm thinking of switching. My current truck is a long bed, and I'm just getting tired of the hassles when parking "the beast." Lastly, with a diesel, we could use the truck lanes when fueling if there's not an RV lane.

So my questions are directed more to Chevy or GMC diesel owners, as I'm looking at the Duramax. First what kind of mileage do you get when towing? Second, what kind of mileage do you get in day to day driving?

[Larrylane]

I had a 2016 2500HD Duramax and recently purchased a new GMC 3500HD SRW Duramax. My situation might be different than yours, but I live in a rural area and not in a city which is better for a diesel than stop and go traffic. We typically put around 6,000 to 10,000 miles on our 5th wheel a year and get 10.5 miles to gallon on undulating roads and around 5-6 miles to the gallon in mountainous areas. As a daily driver we got around 19 on the 2016 and currently getting 18.5 on the 2020 with only 3,200 miles.

Last year we traveled with another couple who had a gas powered truck and they struggled to keep up in mountain areas and they also struggled getting gas at the pumps where we didn't.

We like our diesel and do not regret having it.

[K_N_L]

Our mileage is very dependent on our speed. IF we run in 55MPH zones it can be 10 to 11, at low 60's about 9.5, upper 60's it drops to about 9, through in a a few mountain passes and we're down in the 8's. On our last trip south, we had a 15 - 20 MPH head windwind and biodiesel for most of the day and it dropped down into the 7's for a few 50 mile average periods. My overall mileage for about 22K miles is 9.6 since owning the truck but I seldom use it outside towing. I do see between 17 - 21 for non towing. It would be hard to go back to a gas truck for any towing once you get used to the torque and low rpm's. You didnt mention your camper weight but for reference, we are typically at almost 16K with the garage and everything else loaded.

[ObiRich]

Originally Posted by K_N_L

You didnt mention your camper weight but for reference, we are typically at almost 16K with the garage and everything else loaded.

We have a 2019 Hideout 262RES. If the weights are correct on the label on it, then we're probably a total of 10,000 pounds with our gear and full (or semi full) tanks. Have never weighed it yet.

[roadglide]

Obirich how much weight are you towing . With my 1 ton srw duramax I'm at max weight 32 k on the truck and 25k towing 8.5 is my worst pulling hills in the deep south . In SW I'm averaging 10 mpg. Cruising at 75 I get 19 to 20 . My LML2500 did about the same maybe better towing but it used half the DEF as the L5P. Somebody beat me to the same question on weight.

[Roscommon48]

everyone pulling a large 5th wheel gets about 9-10mpg.


a diesel will help with the mountains and the rpms are lower when going up.


I love my short bed truck.

[JRTJH]

I don't find the "towed weight" to be a significant factor in mileage while towing. I typically get around 10.5-11 MPG towing our Cougar XLite behind the truck. If I double tow/triple tow the boat behind the Cougar (about 2000 pounds) mileage remains about the same. If I tow the Slingshot on its trailer (about 3000 pounds) mileage also seems essentially "unaffected" by the added weight.

What I do notice will affect MPG, is any "wind resistance". If there's a headwind with the Cougar, the wind will affect MPG. If I tow a larger boat (weighing about the same as the Cougar), MPG will go up, probably from the "more streamlined load on the trailer". It's the same when I connect the trailer with my tractor behind the truck. It weighs close to the same as the Cougar, but MPG usually is 13-14 MPG with that trailer in tow.

I'd suspect that, within reason, it's more about "frontal wind resistance" than weight differences of a couple thousand pounds or so.

[travelin texans]

If towing 10k+ regularly in the mountains I'd recommend the the diesel for hp/torque + the engine brake.
Had an '05 & '13 Duramax duallies both got 8.5 to 11.5mpg towing 16.5k 5th wheels at usually 68mph (that was the sweet spot at 1700 rpm). The '13 had noticably more hp & torque, with the biggest difference in the 2 being the engine brake on the '13, set the engine brake, shift to tow/haul, set the cruise & let'er tow. Both averaged 17+/- empty at posted speed limits. As to the DEF usage, the '05 didn't require it & the '13 would hold a 2.5 gallon jug, half of a 5.3 gallon tank, every 3500 miles, towing didn't seem to affect usage. Wouldn't hesitate to buy another Duramax.

[flybouy]

Originally Posted by JRTJH

I don't find the "towed weight" to be a significant factor in mileage while towing. I typically get around 10.5-11 MPG towing our Cougar XLite behind the truck. If I double tow/triple tow the boat behind the Cougar (about 2000 pounds) mileage remains about the same. If I tow the Slingshot on its trailer (about 3000 pounds) mileage also seems essentially "unaffected" by the added weight.

What I do notice will affect MPG, is any "wind resistance". If there's a headwind with the Cougar, the wind will affect MPG. If I tow a larger boat (weighing about the same as the Cougar), MPG will go up, probably from the "more streamlined load on the trailer". It's the same when I connect the trailer with my tractor behind the truck. It weighs close to the same as the Cougar, but MPG usually is 13-14 MPG with that trailer in tow.

I'd suspect that, within reason, it's more about "frontal wind resistance" than weight differences of a couple thousand pounds or so.

There is also a factor of "pressure gradient" that typically has a direct effect on fuel milage. The formula looks something like this.."The greater the pressure in relation to a period of time that is applied upon the accelerator by the right foot the lower the resultant fuel milage". My own theory obtained by personal observations.

[gearhead]

It is what it is, but you could do a deep dive into aerodynamics to find the surface area vs. weight vs. wind speed. I'm thinking there is the factor of putting that resistance on a 11,000 pound truck vs. a 16,000 pound trailer, which I assume is why 18 wheelers have a "spoiler" on the truck to reduce the frontal effects on the much heavier trailer. Then there is the low pressure area behind the trailer that increases drag.
Get back to us when you get the factor of surface area of a low, mid, and full profile 5th.

[gearhead]

Or delve into downforce with a Chaparral race car history lesson and my cousin in law Andy Green:
https://driving.ca/chevrolet/auto-ne...ral-2x-concept

[goducks]

I towed 9200 lbs with a 2012 Ram CTD and loved it. More than enough power for any mtn pass. I live in Oregon so I see many hills and mtns during the camping season.
Effortless cruising on the freeway.
What I didn't like was the emission stuff. I now have a 2018 Ram 6.4 with 4.10 gears. Not near as nice for towing but still does the job. And $9200 cheaper.
Ironically the wife and I were looking at a 2800 mile trip down to Tucson. Just for giggles I figured what it would cost to take my 12 CTD vs my 18 6.4.
It was on $62 more to take the 6.4. Diesel prices are running .40-.50 more along the route and even with 8.5 mpg in the 6.4 vs 11 in the 12 CTD it's still a wash.
Do I miss my CTD? Heck yes. But I don't miss all the extras, like fuel filters, oil, DEF, possible WIF light, searching for quality diesel stations that I can fit in.

[Ken / Claudia]

What I always read in the gas v diesel is the upfront extra cost. Diesel is more than the gas engine trucks, BUT no one points out that the more upfront cost also carries more cost at resale time. Of course condition of any vehicle means more cash.

[jsb5717]

I've never bought a new truck and don't plan to. It's a lot easier to get a good deal on a well-cared-for diesel so the upfront cost (gas vs diesel) isn't as much of an issue.

I've been pulling 5ers for about 30 years and after pulling with a gasser in the beginning I determined that I wouldn't be without a diesel. For me it's much less about economics (although I'm cheap by nature and look for my best deal), and mostly about the towing experience. There's just no comparison to me. The extra torque makes my experience a lot better and less stressful. The better fuel mileage is a nice perk and I get around 11 mpg towing and 18-20 otherwise.

[Keystoned]

There is a big hill north of me called La Bajada going towards Santa Fe. This is the test for me and I usually pass all the gassers while we are doing 60-65 towing. It is at about 6000 feet. Diesel for the win!

[JimJan]

We had a 6.0 gas 2500 Silverado and took out west with a bed camper, pulling a Jeep trailer. Fuel mileage averaged 10mpg. Picked up a 5th wheel and went to a Silverado 2500. Loved the power, Allison tranny and engine brake. Got 11.5 mpg average. Got a larger camper and a 3500 dually Silverado so we are back to averaging 10 mpg. Still love the added power and braking. No plan to go back as trade in value helps with a new one!

[Frank G]

Originally Posted by ObiRich

I have a question or two. I've been toying with the idea of getting a newer truck to pull our 5er with. My current one is a 2009 Sliverado 1 ton, but it's a gasser. Although it does an adequate job pulling it, the fuel consumption is pretty high (get about 7-8mpg), and the engine revs pretty high when going up grades unless I really let the speed bleed off. We live in the mountains, so we do have a fair number of long grades. So I've been thinking about getting a diesel. But that's not the only reason I'm thinking of switching. My current truck is a long bed, and I'm just getting tired of the hassles when parking "the beast." Lastly, with a diesel, we could use the truck lanes when fueling if there's not an RV lane.

So my questions are directed more to Chevy or GMC diesel owners, as I'm looking at the Duramax. First what kind of mileage do you get when towing? Second, what kind of mileage do you get in day to day driving?

You will burn the lead out of 3 pencils trying to financially justify a diesel powered tow vehicle for recreational use. If you want one and can afford it, just do it and enjoy. Follow your own path.

[Dave W]

Regardless od brand, buying a diesel pickup then owning it is expensive. The first shock is that $8-9000 premium just for that engine. The next one is for maintenance. Your gasser as a DIYer will cost about #0 for an oil and filter change. The diesel. Rotella is about $18 a gallon and you need at least three. A filter is ~$20 for the every day version to ~$36 for the top level. Then there are the $$ fuel filters and the $12 jugs of DEF every couple thousand miles. Do these at the dealership, those prices go way up

Fuel mileage - yep, my diesel gets almost 2x the mpg as the gasser I owned before, towing or not - but locally diesel currently is 50 to 70 cents a gallon more which has to be added to the equation.

With all that said, for sure a diesel will haul your trailer better but at a pretty steep out of pocket cost that will buy gas for years before you see any payback, maybe longer if not a long or full timer. For myself, I would look at the new Ford 7.3 gasser if I need a new truck and use the savings to buy lots of gas.

[Badbart56]

It really just comes down to what do you want, and what can you afford doesn’t it? If you have to justify it maybe you don’t really need it. But if you’re not economically challenged and you want it, just get it. Just like a car. I could be driving a Prius, but I like my CTS V!

[LewisB]

Originally Posted by ObiRich

...Lastly, with a diesel, we could use the truck lanes when fueling if there's not an RV lane...

FYI, the above observation in the OP may not be entirely correct. Truck stops with "truck lanes" will likely have much larger pump nozzle sizes (something like 2 inch) nozzles that will not fit in your pickup tank fill spout. To use the truck lanes, you will need to find a truck stop that also has an RV lane or two with the normal (gas station type) fill nozzles. At least, that has been our experience in the western US. Not sure about other parts of the country...

We used to love our gas rig but I got tired of "thrashing" it to get up hills. Now that we own a diesel, it is much more relaxing - there simply is NO substitute for 900+ foot-pounds of torque. And for me, the included "engine breaking" aspect of the diesel and associated safety is worth every bit of the higher price. JMHO