Home Forums Gear Hunting Trucks and Four-Wheel Drives Which diesel truck gets the best mileage?

I'm still driving my '96 Dodge Cummins 12 valve with 5 speed. Usually get 19-20 mpg depending on the wind and quality of fuel.

Does it matter?

You buy a truck to use - as my dad would say - not to look at it.

If you do not have any use for a diesel truck - then you don't buy one. The cost of running a diesel over a gas jobber is about 40% higher due to the fact that the diesel needs constant maintenance.

You are always going to have to watch the filters and the fuel and will always have to keep an eye on everything. If it gels up in the winter - you are looking at a expensive trip to the garage.

A gasoline engine - you stop at the local convenience store and you fill it up with gasoline when the tank is empty and maybe once every 5 or 10 years you change the fuel filter - depending on how many miles per a year you run and what type of fuel you run in it. I have taken many fuel filters off newer style GM gasoline pick up trucks that had 100,000 miles on it - and the original fuel filter and there was NOTHING inside of the filter.

Many times I had to replace the fuel line when I removed the filter in the GM garage when I worked there. Especially if the brake lines rusted out and I had to remove them from the ABS system under the drivers left foot below the floor boards.

A diesel might get good fuel mileage - but when you look at the price of diesel fuel, you aren't saving much over the long haul.

If you had a 7,000 lbs trailer that you towed - you would see a drastic savings, but not just running an empty truck.

The 2007 GMC 6X6 truck we run (Duramax) - 1 ton crew cab, will get 22 MPG towing a 7,000 trailer.
The 2009 Avalanche 1500 4x4, that I run with the same trailer will only get about 4 MPG.

Constant maintenance??? I think you need to lay off dah queens beer.

So far in 58k miles my diesel truck has needed the water pump replaced. Other then that, here is my maintenance schedule:

7500 miles replace oil filter and rotate tires.

15000 miles, replace engine oil, oil filter, fuel filter, air filter, differentian oil and rotate tires.

30,000 miles replace engine oil, oil filter, fuel filter, air filter, differentian oil, transmission oil and filter, transfer case fluid and rotate tires.

Other then that, just keep the tank full of fuel. I've driven it in -30f, and have never had a fuel problem.

That is absolutely the most stupid statement I've yet to read on these forums.

What extra maintenance? A $14 fuel filter that is good for 15,000 miles? Who cares? The oil change costs twice as much on the diesel but the interval is twice as long so in the end the cost is the same. If anything a diesel need LESS maintenance than a comparable gas truck.

My truck gets 22 mpg on the highway, a comparable gas truck would get 15, likely less. Diesel fuel would have to be 50% higher than gas before the fuel costs would even be equivalent. Anything less than that and the diesel costs less. That's before you even take into account that the engine in a diesel will last twice as long as a gas engine. When an engine wears out most people will trade a vehicle resulting in a new truck purchase at roughly half the interval with a gas truck as with a diesel. How much does buying TWO gas trucks to do the work of one diesel truck cost you?

Any way you slice it the diesel is cheaper to operates. Sit down with a calculator and run the numbers instead of pulling stupid statements out of your butt.

[quote=Duquensebeer]the fact that the diesel needs constant maintenance.

Really, I find that interesting since most of us that use diesels for working buy them because of just the opposite of your above statement.

I do agree however if a person tows rarely or doesn't really use their truck as a "truck" the diesel is a waste.

I was recently in a similar situation. A Ford man at heart, but wouldn't touch anything but a 7.3 or a new one and there's no way I could afford a new one and still eat, much less do anything fun.

Contemplated a Ford V-10, few friends have them and the power would have been there for the horse trailer I was thinking of pulling, but they're milage is terrible.

Have a few happy friends with 04-05 Cummins and found a clean '07 with the 5.9. Can't really give detailed fuel usage reports but hand calculated I can easily get 18.5-19.5 empty, slow it down to 60-65 and 21 is doable most of the time. Have scene 22 a few times. My over head is off by about 1 mpg and there's been a few times with the nice SD tail wind I've scene it read 26-27 doing 60. Granted that's a rare thing, but it is always windy here. Just seems more often than not your bucking the wind, rather than going with it.


My folks have an early '03 7.3 Power Stroke, pulling their 32 foot horse trailer with living quarters they get pretty consistently about 10-10.5. Same truck empty is about 15-16 (Club Cab 350, long box).

Oh, paid about the same for my 2500 as a comparable Ford F250 V10



Take a look at a few forums to delete all the emissions crap on the newer ones, but you'll also need a programmer so you don't have to look at the check engine light.

Dude,
every time you opine you put your foot in your mouth. Unbelievable......

These are Imperial gallons,'91 4.0 5speed Cherokee pulling a 7' tent trailer with a canoe up,18MPG;08 6.7 Dodge 6speed manual(a 5speed with a granny gear)pulling 10' tent trailer with 12' tin boat up,23MPG, calculated.That's the same easy 110K(70mph) cruising.I found cruise control will make it worse!.I have seen 13.5liters per 100km on the readout on a run where I am obeying the law ,which is about 30MPG (Imp). Diesel fuel is about 2% cheaper than gas in BC.I'm happy with the fuel economy.

But it's a good point,why waste an expensive truck's milage running empty.

40% YOU say! Holy Cow N Jackrabbits without fur!!!

Well I have an old diesel and it could use some new sheetmetal here and there but it still a strong running 7.3, leaks a little but if I want to pull a friggin house down the road, it will suffice for such a job. Yes, it takes more oil and filters are more money but I don't change it half as often as the V-10 gas (5,000 miles) rig, which is newer a...2006 Superduty F-350.

I think if you factor in the original cost of the diesel engine you might come up closer to the 18% but I just cannot see 40%. I have not had to do anything to the 7.3 other than replace 4 injectors and a water pump. I had a repair job done on the radiator from a bullet during deer season several years ago but no fault of the truck.......tires and brakes yes. It only has close to 290,000 give or take.

I have driven dodge diesels for 15 years, those claiming over 20mpg are mostly full of it unless they are keeping it at a steady 60mph, which out west where I live no one drives that slow.

first truck was a 95 diesel dually 2wd 5 speed, that truck would get about 18mph on the highway, 70-75ish

93 dodge 2wd single cab, the lightest of the diesel truck I owned. it would get 20mpg with a mix of city and highway 18.5 on winter blend fuel and would get a best of 23 mph for some reason driving from salt lake to bloomfield NM, either going or coming, but normally was 19-20 on the highway

02 dodge 4x4 quad cab, 5 speed would get about 17-18 if you keep the speeds below 75, above that and you would get in the 15.5 ish area.

early 04 quad 4x4 auto, this truck didn't have the 3rd injection event. about 16 on the highway at 75mph

06 dodge quad 4x4 auto, this truck was a fuel hog. 14.4 at 80mph maybe a little over 15 at 75, with a mix of city and highway it was less than 15mpg.

all mileage is HAND calculated, which the '06 would read about 4mpg high on the trip computer. all the trucks had stock tire sizes, only one of the 5 was capable of eclipsing the 20mpg number and it was a 2wd single cab with NO emissions controls on it.

I just bought a new ford with 6.7 in it, so far on winter blend fuel I am getting 10% better towing and over 20% better highway mileage than my 06 dodge. I get about 17.5 running 82 mph, I have seen a best of 18.3 with some 82mph speeds some 70mph speeds and some stop and go, I am very happy with the truck and at the end of the day this truck might just well rival my old '93 dodge, when I get to run some summer fuel in it. this truck is a crew cab 4x4 long bed.

I just don't see anyone getting 20+mpg in the newer dodges unless they drive no faster than and keep a steady 60mph. the new dodges don't come with urea injection like ford and chevy so dodge is behind and their motor is choked with EGR and soots the oil very quickly.

CC.
Very informative post. I have two Dodges we use to tow with. One is an 05 we have rolled up about 140K on and a brand new one with less than 10K on it. Your findings are real close to what we have found. I am real interested in how your new F series 6.7 does. With the power levels the 6.7 has I am anxious to see what kind of fuel economy.

Dave

Diesel Power magazine ran a test in the October issue, single rear wheel 2500 and dually 3500 of each brand. Towing and economy. It's a pretty good writeup.

on my trip from tenn. to deap into canada last month i got a low of 22.5 to a hi of 25.8 on my 95 dodge. drove at 65 most all the time. i have over 170,000 on it now.

My 05 cummins with the six speed got 24.5 comming back from Indiana to Pa. Brought a concrete truck back so we never went over 60. Average mpg driving to Montana from Pa. 17mpg. Went out west to pick up two horses 10-11 mpg. I actually used less fuel comming back with two horses on the trailer than I did going out empty, go figure. With all this emissions garbage hanging on these new motors,how can they be as fuel efficent as the 06 and older models.

The older 12 valve cummins in the Dodge pu's did pretty good. Had a 96 that got 21 mpg on a regular basis.

Made a 6 hour each way trip to hunt pheasants last week in my buddies 2008 Dodge 3/4 ton, 6 speed manual, 4x4, crew cab, 4 men, guns, clothes, 2 dog box, dogs and some misc tools/chains/jacks. On the way home I asked what mileage he is getting. He pushed the button and the computer was showing 18.1. He said he hadn't hand calculated anything yet, as he'd just bought it a few weeks earlier used with 33,000 miles on it.

A friend of mine has a 6.7 Cummins in 2008 Dodge 1-ton. He pulls a 32 foot 5th wheel and only gets 16.8-mpg empty at 70mph on interstate. Pulling he gets 12.5-mpg on level highways. His odometer reads 31,000 miles.

Not directly responsive to the OP's question, but we have a 2007 Dodge with the 5.9l Cummins. Last year I took it on a 1800 mile round trip to go hunting in Wyoming. Averaged a little over 70 mph and got a hand calculated 19.5 mpg. This truck has a 6 speed manual and a 3.73 rear end. I added taller tires to reduce the RPM and also installed the Dynatrak front hub kit to reduce the front drive train drag and wear. I just added a 55 gallon Titan fuel tank - it doesn't impact mpg but does impact the miles between fuel stops!

Do you think the Dynatrac kit in the front is going to improve your mileage? Do you know anyone who has installed one of those and checked their mileage?
I thought if I ever have to change a front bearing or hub I'll go with what you did.

That was one of the reasons that I sprung for the Dynatrak installation. I actually think that it helped on the mileage, but it is so tough to keep all the important variables constant for a good and meaningful test. Intuitively (and also from my race car days) a reduction in parasitic drag in the drive trains should convert to more overall efficiency. There are other reasons to make the change, especially as you mentioned when you have to change a hub. Having bearings that are serviceable is nice. Also, just avoiding wear and tear on the front drive train is an advantage. This is a long term truck for us so all of the investments we make to it are to make it more efficient and long lasting. My next project is better fuel filtering.