I am researching a new truck and am considering a diesel (not sure which one yet) or a Toyota Tundra with the 5.7 liter engine. Whatever I get, it will be a used one. I have read about all of the many advantages of a diesel (in the post above--much of which gets a bit emotional) and accept the fact that it is better for towing than a gasser, but of course I will be doing more than just towing and money is a factor. My ultimate goal is reliability, lowest total ownership cost, and towing performance—in that order. Total ownership cost will depend largely on gas mileage both towing and not towing. For those of you who own diesels, what gas mileage do you get when towing at roughly 65mph and with what weight trailer? How about when not towing?My other question is about reliability. I have heard people say that a diesel will last forever, but have also heard that some of the Ford engines can be very maintenance intensive and I understand that fixing a diesel can be pricey. If diesels are truly more reliable than gassers, then that is a big consideration for me, and also may prompt me to buy an older / higher mileage truck than I would get with a gasser. I want something that will be as reliable as possible and that I can keep for a long time / lots of miles. ----------------------------------------------------------------------Edit: I don't need a diesel necessarily. My trailer is only 5k pounds. I may upgrade to something bigger in the future. I just don't like the really, really crappy gas mileage I currently get towing---7-8 mpg with my 06 Tundra (a little underpowered and only gets 14 on the highway unloaded). Matt

I guess a lot depends on the trailer (TT or 5er) that will be towing.

x2 on what you will be towing and where you will be towing it. The Tundra is generally unsuitable for any sort of heavy towing since they have very limited carrying capacity. You need to stick with the 3 more or less American brands: Ford, Fiat(Dodge) or Government(GM)If you are thinking about a 5th wheel then diesel is the way to go unless you stick to the flatlands.I get between 11-13 mpg towing our 5ver depending on headwind and road grade. I get 18.5 or so without the trailer. A gas engine will be substantially worse than that towing.We have had zero maintenance except for a replacement battery strap and a replaced 120v outlet socket. Total time about 30 minutes at the dealer. Not counting the normal oil changes and such. If you buy used be very careful which model year you end up with. Avoid the 6.0L Ford engine for example.

You can't make the blanket statement that diesels are more (or less) reliable than gassers because everything depends on whether the manufacturer did the job right in the first place. IN THEORY, diesels should outlast gassers by virtue of lower operating speed AND the fact that in order to withstand the higher compression ratios, the block, head, rods, etc HAVE to be stronger than they are in a gasser. But as GM proved in the '70s, it is possible to build a diesel that will blow up within 40,000 miles because it was designed all wrong.My advice here is to research the reliability of each of the candidates, and not rely on any vaunted class theoretical reliability hocus-pocus.Now, my TV is a diesel, albeit a Jeep Liberty. It has a 2.8 liter, 4 cylinder diesel, and I get around 26 mpg overall not towing, and sometimes as high as 34 mpg. Towing the 5,000 lb full-height/width TT that is the maximum it is rated to pull, I average about 14 mpg, but I have gotten as high as 16 and as low as 9 (albeit towing that rig into a 50 mph head wind, a mistake I'll not repeat).I also have to say that this particular vehicle has been the least reliable vehicle I've ever owned in my 50 years of driving. But that is NOT due to it's being a diesel, it is due to it's being one of only 15,000 in the US, a test marketing vehicle, that was poorly thought out. I've worked most of the bugs out now, and plan to keep it, but I wouldn't buy another one.

If a Toyota is in mix than you don't need a much of a pickup. So if whatever your towing is half ton towable, I would use a gas pickup over any diesel. I have had 5 Duramax trucks my 08 Duramax has never missed a day of work in just under 100K miles. They are almost in my view totally dependable and powerful. A head gasket in my 5500 is the most I have ever spent in a million Duramax miles and that was due to a dumbassed employee. Yet I would still buy a gas (I would get a 2500HD if it were me) over a diesel for your purpose. If your pulling real heavy than it is a no brainer, but if gas is an option at the weight your pulling at, than gas is a better choice in my view. I never thought that way until I bought my 2012 2500HD with a 6.0 liter.

ksss wrote:If a Toyota is in mix than you don't need a much of a pickup. So if whatever your towing is half ton towable, I would use a gas pickup over any diesel. I have had 5 Duramax trucks my 08 Duramax has never missed a day of work in just under 100K miles. They are almost in my view totally dependable and powerful. A head gasket in my 5500 is the most I have ever spent in a million Duramax miles and that was due to a dumbassed employee. Yet I would still buy a gas (I would get a 2500HD if it were me) over a diesel for your purpose. If your pulling real heavy than it is a no brainer, but if gas is an option at the weight your pulling at, than gas is a better choice in my view. I never thought that way until I bought my 2012 2500HD with a 6.0 liter.I would never buy a 250/2500. The price difference is minor when you are talking about the prices of one of these trucks new. And except for a heavier suspension the vehicles are identical. You may really regret saving a couple hundred bucks and then finding out down the road that you can't pull some rv you want. I do agree that if you are sure a half ton will work for you then get one but not a Toyota.

Diesel Gas Mileage and Reliability??? | Good Sam Community

25 Replies

dodge_guy
Explorer II
Apr 09, 2014
Does a diesel get good gas mileage? ;)
rowekmr
Explorer
Apr 09, 2014
With reliability and total ownership cost as the prime considerations I would recommend a gasser. I don't know much about the foreign ones but a good half ton truck or suv from the Big 3 all seem to be good. I have had a few older gassers before and besides maintenance the engines themselves were rock stable it was just the accessories and body power options that occassionally needed service. No need for plugging in, special fuels/additives, expensive quirks which some diesel have.
I had a V10 Excursion that got 16 mpg empty and 7-9 mpg towing 8500# TT.
My current TV which has some mods can get 23 mpg empty (15 avg) and towing same TT get 12+ mpg. I just towed a more aerodynamic car hauler trailer with an empty F250 about 10K and got 15 mpg which is only slightly less than the gasser Ex (6.8L) and Navigator (5.4 4V) which were both around 16 mpg would get empty. While I can speak on its towing power (great), cost of ownership/modding (high), I can't speak on reliability because I haven't put a lot of miles on it yet but this drivetrain has a bad reputation.
bowler1 wrote:

My ultimate goal is reliability, lowest total ownership cost, and towing performance—in that order. Total ownership cost will depend largely on gas mileage both towing and not towing.

For those of you who own diesels, what gas mileage do you get when towing at roughly 65mph and with what weight trailer? How about when not towing?

My other question is about reliability. I have heard people say that a diesel will last forever, but have also heard that some of the Ford engines can be very maintenance intensive and I understand that fixing a diesel can be pricey.

----------------------------------------------------------------------
Edit: I don't need a diesel necessarily. My trailer is only 5k pounds. I may upgrade to something bigger in the future. I just don't like the really, really crappy gas mileage I currently get towing---7-8 mpg with my 06 Tundra (a little underpowered and only gets 14 on the highway unloaded).

Matt
Lantley
Nomad
Apr 08, 2014
bowler1 wrote:
Hi,
T Here is some additional information that may help to define my question better:

1. I tow a 5k pound trailer and may get a slightly bigger one in the future, but not a 5th wheel any time soon.

Matt

A 5000 # trailer does not require a diesel. Your solidly in Tundra Territory. For your requirements go with the Tundra diesel is not required.
Tystevens
Explorer
Apr 08, 2014
Matt, here's my $.02. I've towed the same TT (avg loaded weight of probably 6000#) w/ 3 different vehicles now (soon to be a 4th): an '05 1500 Suburban 4 spd (4.10 gears), a 2500HD turbodiesel, and a 2010 1500 Suburban 6 spd.

Towing mileage @ 65: '05 Suburban -- 8-10 mpg.; '06 diesel -- 10-12.5 mpg. '10 Suburban -- still around 9-10 mpg, but performance is much better due to the 6 spd.

Non-towing mileage: '05 Suburban 12-17 mpg; '06 diesel -- 13-20 mpg.; '10 Suburban -- 14-21.5 mpg

Never had a single substantial problem with any of them. I don't know you could say that diesels are more 'reliable.' The engine might go for more miles, but there are still lots of things that could need to be fixed.

Cost to buy is going to put the diesel behind the others in a pure economic analysis, I'm afraid. Like others have said, it is going to take a lot of towing miles to make up the cost of the diesel, especially since (here, at least), diesel fuel costs at least $.50 more than regular. But the towing performance was remarkably effortless. Literally put it in cruise at 68 mph and it went down the road in 6th gear. Through the mountains, into a head wind, wherever. I actually looked forward to towing w/ my diesel. Keep in mind that I'm in Utah, so we have mountains pretty much any direction we go.

I'd think a more 'modern' 1/2 ton w/ 6 spd transmission will be a good upgrade for you. I was surprised how much of a difference the 6 spd in my '10 Suburban makes compared to my '05. Where the large gaps between gears in my '05 sent the engine screaming to the redline all the time, the 6 spd seems to always have a gear right where I need it. No, it isn't pulling down the road in 6th hardly ever, but having the range of 3rd-5th to work with is much nicer than bouncing between 2nd and 3rd (no, my '05 never was able to tow in 4th gear, either, despite having 4.10 gears). Much nicer towing experience, even if it isn't any more fuel efficient.

I'd also put a plug in for the Ford Ecoboost, although I haven't towed with it yet. I don't think it will break 10 mpg towing, but from what I can tell driving it unloaded, it is going to tow very easy due to the low torque curve.

Good luck!
camp-n-family
Explorer
Apr 08, 2014
3. I certainly don't NEED a diesel, but am looking for a way to get better towing mileage than the current 6-8mpg I get with my 06 Tundra which is a bit underpowered--not sure what would happen if I tried to tow my current trailer in a mountainous area--current truck has 270 hp and 330 ft/lbs torque.

The current 5.7l (381hp, 400tq) mated with the 6speed and 4.30 gearing will run circles around the old 4.7l. It will tow better and get better mileage while doing it.

My '07 averages 9.8mpg towing my 7800lbs 31' tt at 65mph and that's with a lift and oversized tires.

Unless you are towing big weights or a lot of miles you will likely not recover the extra cost of the diesel.
grampscamper
Explorer
Apr 08, 2014
bowler1 wrote:
Hi,
Thanks for the responses. Here is some additional information that may help to define my question better:

1. I tow a 5k pound trailer and may get a slightly bigger one in the future, but not a 5th wheel any time soon.

2. The terrain I tow in will be varied. Probably not a lot of towing in the mountains, but I am in the Army and move a lot so I am not sure what the future holds.

3. I certainly don't NEED a diesel, but am looking for a way to get better towing mileage than the current 6-8mpg I get with my 06 Tundra which is a bit underpowered--not sure what would happen if I tried to tow my current trailer in a mountainous area--current truck has 270 hp and 330 ft/lbs torque.

4. Reliability--yeah that is kind of a blanket statement to make. I guess I can say that I know the reliability of the Tundra and it's great. I am curious if most diesels can / will exceed this level of reliability and engine life. I currently have 165k on my 06 Tundra.

5. Cost--yeah I know that the hobby isn't cheap; however, given that I like this hobby I want to minimize my total ownership costs as much as possible. I will do the math based on my projected use. Spending half the amount on gas while towing sure would be nice....but only if it truly pays off in the long run.

6. Useage over the next several years will probably see lower miles and most of them towing. My wife is having a baby so the truck will be hers and will make short trips around town ocassionally and will no longer be used for commuting. Not making cross country trips, but our trip mileage will exceed the daily driving miles until she goes back to work in a few years.

thanks for your help!

Matt

Matt, I have owned the same truck as yours, the newer Tundra with the 5.7 & now the Ford with the 6.7 diesel. Comparing either Tundra to the Ford is like comparing an apple to an orange. I'm not saying one is better than the other but they perform quite differently. The Tundra with the 5.7 has lots of power, good torque and gets reasonable mileage. I think the Tundra would be a good choice for your application. If you were pulling a 5th wheel I would definitely go with the diesel. I can tell you from personal experience that the diesel does a much better job of towing. The pulling power of a diesel is absolutely incredible. I couldn't believe the difference. I average about 11 mpg towing a 5th wheel & high teens when I'm not.
I don't want to start a brand war but if I was pulling a trailer like yours I would likely still own a Tundra. I feel the diesel is the best choice for my application. The difference in cost between a gas truck and a diesel will certainly buy a lot of fuel. If your wife is driving it around town & doing short trips a diesel may not be a good choice.
Good luck with whatever you decide.
agesilaus
Explorer III
Apr 08, 2014
Get one of the turbo half ton gasser units.
bowler1
Explorer
Apr 08, 2014
Hi,
Thanks for the responses. Here is some additional information that may help to define my question better:

1. I tow a 5k pound trailer and may get a slightly bigger one in the future, but not a 5th wheel any time soon.

2. The terrain I tow in will be varied. Probably not a lot of towing in the mountains, but I am in the Army and move a lot so I am not sure what the future holds.

3. I certainly don't NEED a diesel, but am looking for a way to get better towing mileage than the current 6-8mpg I get with my 06 Tundra which is a bit underpowered--not sure what would happen if I tried to tow my current trailer in a mountainous area--current truck has 270 hp and 330 ft/lbs torque.

4. Reliability--yeah that is kind of a blanket statement to make. I guess I can say that I know the reliability of the Tundra and it's great. I am curious if most diesels can / will exceed this level of reliability and engine life. I currently have 165k on my 06 Tundra.

5. Cost--yeah I know that the hobby isn't cheap; however, given that I like this hobby I want to minimize my total ownership costs as much as possible. I will do the math based on my projected use. Spending half the amount on gas while towing sure would be nice....but only if it truly pays off in the long run.

6. Useage over the next several years will probably see lower miles and most of them towing. My wife is having a baby so the truck will be hers and will make short trips around town ocassionally and will no longer be used for commuting. Not making cross country trips, but our trip mileage will exceed the daily driving miles until she goes back to work in a few years.

thanks for your help!

Matt
mrkoje
Explorer
Apr 08, 2014
bowler1 wrote:

My ultimate goal is reliability, lowest total ownership cost, and towing performance—in that order. Total ownership cost will depend largely on gas mileage both towing and not towing.

1. Reliability
2. Low cost
3. Towing performance

Hate to break the news to you but those 3 don't really go together to well. You might want to find a new hobby.

Best of luck to you!
hmknightnc
Explorer
Apr 08, 2014
We need a lot more definition on what your trying to pull and do. If what your trying to pull is capable of a Tundra then you dang sure don't need a diesel. A Tundra and any current diesel pickups are just in completely different worlds for RV towing.

As far as reliably goes I have an '06 Cummins with 160k+ miles about 100k of that towing 18k#. Truck has never seen a wrench except routine service per the severe duty maintenance schedule. I also have an '05 factory tow equipped Tahoe with 172k miles, about 100k of that pulling 6k#, it also has never seen a wrench except for routine maintenance. Both of these trucks are still on the road and run like or better than new. No plans to trade either one anytime soon.