Gas vs Diesel – Which to buy?

Gas or Diesel Motorhome?

So, you’re ready to buy a motorhome and all you can find on the Internet as far as gas or diesel goes is opinion, and in most cases, opinion that is not fact based! Well let’s take a few minutes to drill down to the FACTS!

What are the key differences between Gas and Diesel RVs?

The fact of the matter is, in most cases, both “gassers” and “pushers” have engines that are designed for trucks. The best ones in my opinion are the Ford V-10 Triton, the GM Workhorse (8.1L GM Vortec) W-20 to 24, and the Cumins ISX.


Gas units are cheaper to buy initially, require less expensive maintenance, but yield poor gas mileage, usually around 7-8 mpg for the newer coaches and less than that for most older ones, and wear out quite rapidly. Most gasoline engines in motorhomes are considered to be “very tired” when they have only about 100,000 miles on them, with the exception of the Ford V-10 Triton.

In older gas motorhomes (prior to 1998), the Chevy P-30 chassis with a 454 CID V-8 engine could handle only a 16,000 lb. load, whereas the Ford F53 chassis with a 460 CID V-8 engine could handle a 17,000 lb. load. In l999 Ford came out with a totally new F53 chassis with a 6.8L V-10 engine, that came in three load ratings of 15,000, 18,000 and 20,500 lbs. A couple of years later, the Chevy Workhorse chassis with an 8.1L V-8 engine came on the market and had load ratings of 20,700 lbs., and 22,000 lbs. And then Ford also came out with a 22,000 lbs. chassis, which Workhorse followed with a 24,000 lbs. version. As you can see, the newer motorhomes have higher load carrying capacities than the older motorhomes.

All “gasser” motorhomes manufactured in the United States during the 2000 model years or so are built on either the Workhorse chassis (no longer associated with Chevrolet) or the Ford V-10 F53 chassis.


Diesel Pusher
Diesel Pusher


Diesel units cost more to buy, yield better fuel mileage, somewhere between 9 and 14 mpg, and require more costly maintenance, some using 32 quarts of oil for an oil change, but diesel engines are much more robust — easily going up to 500,000 miles without an overhaul. Diesel motorhomes generally come on three different chasses — Oshkosh, Freightliner, and Spartan. The load carrying capacity of the diesel chassis motorhomes is anywhere from 22,000 lbs. to almost 60,000 lbs.

The three most common diesel engines in motorhomes are Detroit, Cummins, and Caterpillar. Diesel owners have very strong opinions about why their chosen engine is better and can easily get involved in intensive disagreements.

Diesel engine coaches are usually “pushers” with the engine located in the rear of the motorhome making the front very quiet, and conversations between driver and co-pilot are in normal speaking voices. The downside, for many RVers, is the loss of storage under the bed taken up by the rear engine.

Until fairly recently, when someone mentioned a diesel-powered motorhome, just about all of us immediately thought of diesel pushers, which have been around for decades. Now, however, there are two new entrants to the diesel motorhome group:

  • Diesel-powered Class B motorhomes
  • Front-Engine Diesel motorhomes (on a truck chassis)

Diesel-Powered Class B motorhomes. The new Sprinter chassis from Chrysler, is outfitted with a Mercedes-Benz diesel engine that is quite fuel efficient. As the popularity of this chassis increases, so does the different number of firms that are now marketing a Class B motorhome on this chassis.

Although the basic chassis and body is rather slim, looking almost too tall for its width, the RV manufacturers have begun to make some interesting changes in order to pack more RV features into the small space. Several manufacturers use only the chassis and front end, putting their own wider, fiberglass bodies on the Sprinter chassis.

FRED—Front Engine Diesel.—Although there are some folks who might argue that the Sprinter is also a front-end diesel, this term is usually used to refer to those much larger motorhomes, most often a variation on a Toy Hauler, that has been put on a Freightliner truck chassis. These motorhomes and Toy Haulers still have the Freightliner front end on them, but each manufacturer adds their own living quarters.


So we’ve covered most of the differences between the gassers and the pushers. You have to make a choice based on usage! Here are some of the consideration points:


  • Cheaper to buy, but less resale value
  • Cheaper to maintain
  • Light duty truck frames are easier and cheaper to service
  • More service facilities
  • Gasoline is cheaper to buy but you get fewer miles per gallon
  • Less expected engine life
  • Noisy motor under the driver’s cab, excessive heat
  • Less wall space due to the entry way in the center of the coach
  • Less towing, HP, torque, carrying and gross vehicle weight on the newer models
    NOTE: Older models up to about 2008 are very compatible


  • Expensive to buy, but better resale value
  • Expensive to maintain, but fewer service intervals, still more than gas
  • Heavy duty truck frames with air and hydraulic braking systems
  • Air bag suspension for a better ride
  • Fewer service facilities
  • Diesel is more expensive, but you get more miles per gallon
  • Higher mileage engine life
  • Quiet ride with the engine in back, less heat in the cab
  • Quiet sleeping on generator with the genset up front
  • Better floor plans due to the entry way up front
  • Better gross vehicle weight and carrying capacity
  • Higher HP and torque in the newer models for better towing and hill climbing
    NOTE: Older models up to about 2008 are very compatible
  • Typically better constructed with upgraded appliances and better designs

So what are you going to use it for is the real question!

If you’re planning on using it for cross country trips and running a lot of miles, the diesel is the no brainer! But if you’re like the typical, average RVer, gas is probably a better way to go.
Did you know that the average RVer only drives about 3,500 miles a year?

Considerations are: Where you will be going, mountains or flatlands? How many miles a year? What are you towing? What is your budget? What quality build level do you want?

Now you have all the facts about gas vs diesel. The final decision is up to you!

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