Gas vs Diesel: What’s the Best RV Engine?
There’s a debate that goes on among RV tailgaters that has nothing to do with toilet paper.
Gas or Diesel?
What’s the best type of RV engine for Class A RVs for RV tailgating?
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Advantages of a Diesel Engine RV
The biggest advantage of the diesel engine is the power the engine produces. How else are you going to push or pull 34,000 pounds around the United States?
Oh wait, let’s add another 6,000 pounds for a tow car.
That’s a lot of weight to be moving around, especially if you are trying to go up steep mountain climbs. A diesel engine really shines when you are towing up the mountains out West.
But even in the mountains on the East Coast or through city driving. Diesel engines have power and who doesn’t want the power?
Power and Gas Engine RVs
Have no fear though, if you are in a gas engine RV, you’ll still be able to climb those mountains.
You’ll probably just go at it a bit slower. If you’d go up a mountain at 50 mph in a diesel, you’ll probably go closer to 30 mph in a gasser. But you’ll still get there.
Also, gas engine RVs are typically shorter and weigh less. So they need less power to get up those mountains.
Stopping the RV
Whether in a gas or a diesel RV, you still need to stop the RV. Especially when coming down those mountains.
A diesel engine has engine brakes/retarder. This makes descending mountain grades much safer and less likely to burn out your regular brakes.
The gas engines have a tow/haul mode that helps control the descent but the engine brakes on a diesel engine are much better.
How Big Do You Want to Go?
Diesel powered RVs can be VERY big.
In fact, if you want a large RV, you may have to go with a diesel. You won’t find too many gas RVs over about 38 or 40 feet long.
If you want a large home on wheels and want to life the luxury lifestyle, then a diesel RV is probably the way to go.
On the other hand, if you want to visit more national and state parks or not be so limited in the campground or boondocking spaces, you’ll want a shorter RV. They can still be as luxurious if you pay the price, but the gas RVs are typically smaller.
Yes, you can get short diesel powered RVs but there is definitely an upper limit on the gas powered RVs.
Advantages of a Gas Engine RV
The biggest advantage of a gas engine RV and the biggest disadvantage of a diesel engine is the cost.
I have a Tiffin 34PA. For the 2019 models, the MSRP is typically around $198,000, depending on which features you get on and above the floor plan itself (some features include upgraded generators, solar prep or solar panels, backsplashes, tile, upholstery, etc).
The comparable diesel model is the Allegro Red 37 PA. It’s the same floor plan, just three feet longer which gives you a nice closet in the back of the bedroom. The MSRP is typically $336,000, again depending on features you select.
That’s $138,000 for a diesel engine! And that’s just the upfront costs, not including maintenance.
Right now, gas is also cheaper than diesel in most places in the United States. That may be offset with the fuel efficiency of diesel versus gas. It may be the difference between 8 mpg to 10 mpg. By the time you run the generator for all your AC and power needs, this isn’t going to make a big difference.
Personally, I wouldn’t make the decision of gas vs diesel engines on the current price of gas vs diesel fuel. It could switch again tomorrow and the fuel efficiency may wipe out any savings on the price of the fuel.
Speaking of Fuel
While the efficiency may wipe out the savings you get from buying gas, there is another advantage of gas over diesel when it comes to the fuel itself. Availability and ease of filling up!
Sure, diesel is readily available throughout the US. But how many of those gas stations can you fit your RV into? And they may only have one or two pumps that are diesel, mostly for the heavy duty pickup trucks.
Once you get away from the highway fuel stations, it can be pretty difficult finding gas stations that are easy to get your giant diesel pusher into.
My experience is that there are a lot more readily available gas pumps than diesel pumps that are going to be accessible. If nothing else, just because there are more gas pumps to choose from – if this station doesn’t have one that is accessible, you can go to the next station.
I know one of the big decision points for me getting a gas-powered RV was that I have a Costco nearby that is easy to get in and out of, even with my 37 feet of RV. Meanwhile, there’s not a good spot to fill up an RV with diesel between my house and Georgia Tech. It’s probably a good 10 miles to find diesel.
And in Atlanta traffic, that could be two hours or more on a Friday afternoon heading to the tailgate. Sorry, I’d rather be tailgating than trying to find fuel.
Don’t Forget about DEF
Diesel engines also need DEF to keep on going.
Diesel exhaust fluid (DEF) is injected into diesel engines (not into the diesel fuel). It is to help reduce nitrogen oxide emissions, you know the stuff that produces smog.
Gas engines don’t need this additional additive while diesel engines do.
DEF has some problems in cold temperatures and high altitudes. So if you aren’t constantly driving up and down those mountain roads and will be sitting still for awhile, the gas engines typically work better in cold weather.
DEF is another fuel cost to take into consideration when you are balancing out the pros and cons. Also, it’s another liquid that you need to keep stock of and probably keep on hand.
Maintenance on Gas and Diesel Engines
When it comes to maintenance, gas engines typically win in a heads up comparison of proper maintenance.
Mostly because gas engines are easier to take care of – you may even be able to do a lot of the maintenance on your own. Especially the periodic oil changes.
However, diesel engines don’t need the oil changed as often as you need to change the oil in a gas engine. So time can be a consideration. But when they do need an oil change, it’s going to be three times as much oil.
When you do have to take the RV in for engine maintenance issues, gas engines are going to be cheaper to work on. Most of the gas engines are Ford, so any Ford technician can typically work on the RV gas engine.
Meanwhile, diesel engine technicians are not as widely available and when they are available, are more expensive. You may find that diesel technicians don’t want to work on RVs, only large tractor trailers.
Noise and Gas and Diesel Engines
Another consideration for many RV owners is the noise (and heat!) from the engines.
For most diesel RVs, the engine is in the back of the RV. For gas RVs, the engine is typically in the front.
This means when you are driving, the noise and the heat from the engine will be in the back of the RV on a diesel. Many people will say this is a big advantage of diesel engines over gas engines, since you’ll have a quieter drive.
I’ll tell you that my experience is that the engine noise isn’t a deal breaker for a gas RV though.
I’ve done some completely unscientific testing on some trips in my gas powered RV. The decibel ratings have been about 68-73 dBs, even when revving the engine up on some small inclines or accelerating in traffic.
This is basically the sound of your dishwasher running at home. You can talk over your dishwasher, right?
Noise and Generators for Diesel RVs
On the other hand, the real advantage I see when it comes to noise and diesel engines is that the generator for a diesel RV is typically upfront.
This means that you are not sleeping on top of the running generator while tailgating or boondocking. For many people, this will mean a better night’s sleep.
That also means the exhaust is not right at your bedroom, making it safer (hello carbon monoxide poisoning).
See Also: GenTuri RV Generator Exhaust System
A gas engine requires a drive shaft from the engine to the back tires. This takes up room in the basement compartments.
It’s why a diesel RV has all those cool full size pass-through bays while gas RVs typically have the smaller basement compartments.
So if you want all the tailgating tents, chairs, bars, stereo speakers, and whatever other outside gear you can think of, then a diesel RV has better basement storage space.
That’s totally a reason to pick a diesel RV, right?
More Minor Considerations
So we’ve hit the biggest considerations in the debate for gas versus diesel RV engines.
But there are some more, minor considerations that are worth a mention.
In a gas RV, there is an area that many refer to as the doghouse.
It’s a compartment on the floor between the driver and passenger seats. Think about where the cupholders are for many gas RVs.
The doghouse is necessary to contain all the engine “things” <-- yep, technical term here.If the doghouse is not properly insulated, it can make the noise and heat inside the driver's compartment a lot louder and hotter when the engine is running.In the diesel RVs, the doghouse is going to be in the back. Say, around the closet or bed area.This can make the bedroom be weird. Or take up closet space.Pick your poison, you'll have this weird interior space somewhere.
Diesel RVs typically have air horns which are much louder than the electronic horns found on most gas RVs.
There’s nothing quite like an air horn to scare the beejeezus out of someone that cuts you off in traffic. Or to celebrate a touchdown or win.
Sure, you can upgrade but the air horn is standard on diesel RVs.
No, not the safety airbags you find in a car. Airbags, in this case, are part of the suspension system on diesel RVs.
Most gas RVs use the more common and traditional spring suspensions.
The air suspension is more favored though as they dynamically work to increase or decrease air pressure to provide the smoother ride.
You can also “dump the airbags” when you get to the tailgate lot to help level the rig. Of course, that also means that you need to air them up when you get ready to leave, meaning it’ll take a few extra minutes to leave.
Neither a gas nor a diesel RV is going to be an appreciating asset. Very rarely will the prices go up after you drive the RV off the dealer’s lot. (I won’t say never, hello Airstreams)
When it comes to holding value, most people say that diesel RVs have better resale value.
But here’s the thing, when you do the math, it’s about the same. Sure the absolute resale price is going to be higher than a gas RV.
But they started off higher as well.
I’d be much more willing to say that you won’t end up upside-down on an RV loan with a gas RV than with a diesel RV. If you have x dollars to put down on the RV, you’ll have a lot more “equity” in the gas RV than the diesel RV. Your payments will go a lot further in paying down the principal on your gas RV loan.
See Also: Tax Time: Does An RV Qualify for Tax Deductions?
What’s the Best RV Engine Type for You?
Obviously, I went with a gas powered RV as my choice when it came time to pick the RV. I love my Tiffin 34PA.
But that doesn’t mean it is right for you! There are a lot of diesel engines in my RV tailgating lot.
Some questions to consider:
- What’s your budget? Price is going to be a big driver in your decision on gas vs diesel engines.
- How will you use your RV? Will you be mostly stationary or will you be driving a lot?
- How often are you driving? Every weekend, every week, every month?
- What kind of driving will you be doing? Mostly flat coastal areas or tall mountains?
- Will you be towing a car? Diesel RVs typically have higher weight towing capacity and more power to tow.
- How big of an RV do you want? Diesel RVs are typically bigger than most gas models.
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I sure was hoping to learn something new regarding this age old dilemma. Especially with the latest technology with both fuels and engines. 40 year RV owner of too many models to list and about the same as a fleet manager. I was always sold on diesel up until the last 15 years. The increase in maintenance costs during this period on my fleet and diesel pushers and personal trucks have me looking closer every year to going back to diesel for my RV. I was hoping you were going to focus on that aspect more than you did. Thanks anyway.
John, For me, the cost of maintenance was a big deal in choosing to go gas. A friend had a really nice diesel – one that when he bought it new was approaching $1 million. He had a problem with a sensor, which itself cost less than $5. But to get to where that sensor was located, it took them $5,000 worth of labor pulling half the RV apart and putting it back together after replacing the sensor. I told him then that even if he gave me his RV, I wouldn’t be able to afford it – not with maintenance costs like that.
I’m quite happy with my gas Class A motorhome. I have a nice Costco gas station near home so I can easily get good, cheap gas. The performance is great, even when towing and in mountains. Sure, I’d like to have the extra basement storage space and the generator in the front for tailgating/boondocking. But not worth the added expense to me.
Oops, meant to say ” going back to gas” not diesel.