The beach at Lo de Marcos, Nayarit, Mexico. Photo taken yesterday morning!
Where are Kevin and Ruth right now? Lo de Marcos, Nayarit, Mexico.

Where are they going next? Color Marino RV Park, Teacapan, Sinaloa, Mexico. Arriving Saturday afternoon for a three night stay!

Monday, March 12, 2018

Gas motorhome, or diesel motorhome?

If you're shopping for a motorhome, do you choose gas, or diesel?

When we bought Sherman, the answer was easy because we didn't want to spend a lot of money.

But if money were no object, diesel would definitely be the way to go.

In short, they typically get better fuel economy, they have more torque and are therefor better at climbing hills, they have better braking, and are quieter to drive. And they retain their value better.

Let's take a look in more detail...


Diesel powered motorhomes get between 8 to 12 mpg. Gasoline units typically between 6 to 10 mpg. Obviously there are a lot of variables, but in general the diesel is better.
An interesting fact... while it can take up to 8 minutes to fill an 80-gallon tank of regular gas, it only takes about 3 minutes to fill a 100-gallon tank of diesel fuel.

Speeds at Different Grades

Diesel powered RVs maintain higher speeds on grades without downshifting and with almost half the noise.
Diesel coaches deliver 50% more torque, which results in stronger uphill acceleration in coaches and less downshifting.
The result is that going up a hill with an 11% grade, the diesel-fueled RV maintained a speed 7 mph greater than gasoline.

Noise Comparison Levels

Diesel coaches use air suspensions for a smoother and quieter ride, resulting in less driver fatigue, while gasoline powered RVs use multiple-leaf spring suspensions.
Since diesels are generally used in a pusher layout configuration, not only is the noise level less, but it is also further away from the driver, resulting in less fatigue.
Not only are diesel generators quieter, but the generator is located 30 feet away from the bedroom on a diesel pusher, resulting in significantly less noise as customers relax.
On hills, the diesel climbed with 20 dB less noise, which is 4 times quieter than gas, and equivalent to the difference of a normal conversation vs. a food blender.


Supplement exhaust braking systems on diesel coaches provide drivers with greater confidence going downhill, with a reduced risk of glazing, overheating or fading, which increases better control on steep downhill grades.
During an emergency brake maneuver, the diesel powered coach stopped 50 feet shorter than our gasoline coach and had much lower brake temperatures after extended braking.

Cummins Engine Division recently published an video series comparing gas and diesel RV's. Interesting videos, although with an obvious slant towards diesels! You can view the rest of the series here...

Gas or Diesel RV

If you're in the market for a motorhome, it's worthwhile to view the videos and see what the options are.

Any way you look at it, it's obvious that diesel fuel is the choice to make. The obvious downside? They cost more money to begin with.


  1. My friend with a diesel pusher calls it his $5,000 motorhome, because anytime something goes wrong with it (which is often), it costs him $5,000 to fix it. As you have shown, an older gas Class A will get you the most fun per $.

  2. Maybe a more interesting choice to consider is used vs new. How would the gas vs diesel choice interact with the used vs new choice? Would there be a difference?

  3. In addition to better mpg, diesel used to cost less per gallon than unleaded. Unfortunately that's rarely the case now---though diesel still usually costs less per mile driven.

  4. I still prefer the gas class C then the diesel pusher class A. With the higher price of diesel here in the west, the cost of fuel per mile is about the same. Never felt comfortable taking the new diesel into Mexico, with gas, not a problem. Sure Mexico will soon have the ultra low sulfur fuel, but I have heard that for about the last three years. Driving in windy conditions the Class C holds the road far better than my class A did. It was like a white knuckle ride with the A. I am being polite saying it that way, as I shouldn't publish what I usually called it. These comparisons are always interesting, but then it is similar to the fact that there is chocolate and vanilla.

    1. ULSD is currently available at many Pemex stations in Mexico, with a full roll out promised to be complete by December. We have had two newer diesel rigs in the current caravan, neither have had issues.

  5. I think it is not worth it anymore, if you add evrything up, initial cost, price of diesel about the same as gas, maintenance and repair are very expensive and you need specialize shop to do the work, all the anti pollution sensors.... night mare. We used to have a Sprinter Diesel class B, we traded it for Gas class A. We hated camping at the dealer for days waiting to be repaired and for parts. Mercedes was 150$ per hour rate, yes they supply coffe and fancy pastry but...🤑🤑🤑 Gas engine any garage can work on them and there is gas everywhere. My thought.

  6. It does seem that newer diesels have gotten way more complicated, but so are gas units these days. My '97 Cummins turbo diesel is just getting broken in at 170,000 miles---how long do typical gas engines last? Here in the southwest, diesel costs 17% more than unleaded but gets 25% more mpg, according to Kevin's figures. So that's a win in my book.

    1. You can not base your decision on fuel economy only when comparing Gas and Diesel. What you are going to do with it and your budget is a lot more important . If money is no object then Diesel is the way to go for all the plus including maintenance. Check out this video


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