Pros and cons of a Diesel?

[wijames2002]

I've never owned a Diesel in anything but have a chance to get a nice RV with a diesel from a neighbor. What are the pros and cons of a Diesel over a gas motorhome?

[SeilerBird]

Diesels cost more initially and are worth more when you go to sell it. A wash.

Diesels cost more to maintain but the engine lasts longer. A wash.

Diesels get better gas mileage but the gas is generally more expensive. A wash.

Financially I consider the diesel vs gas argument a complete wash.

Diesels are quieter than gas. Diesels generally ride better due to air suspension. But you only spend on average 5% of your time driving an RV so I don't consider either one of these to be really big huge issues.

Realistically I consider the diesel vs gas debate to be a question of the right tool for the right job. If you are doing a lot of mountain driving or towing a toad then a diesel is your best bet. Otherwise you are better off with a gasser.

I have owned both types and neither one seemed to have any advantage for me, they are just different. It is mainly an apples oranges comparison. A lot of men seem to think diesels are more macho but I think that is a horrible attitude.

[RedandSilver]

I've never owned a Diesel in anything but have a chance to get a nice RV with a diesel from a neighbor. What are the pros and cons of a Diesel over a gas motorhome?

A "nice RV with a diesel" doesn't tell us much.  What diesel engine is in the RV? What RV and what is it's length? How old is the unit? etc.

I bought my first diesel anything because I knew I would be towing a trailer and had to go over mountains to get to good weather.
Diesels have a lot more torque so for towing that is a benefit. 

[Back2PA]

Granted my previous rig was an underpowered, very large gas rig with an old school (460) engine, but when I sold it I remember telling myself I wasn’t getting another unless I could afford a diesel. The gas just wasn’t designed to run at full throttle climbing hills, resulting in warped exhaust manifolds and marginal cooling. Plus the noise and heat off the doghouse made the drive less than enjoyable. Some of those issues are moot with newer gas rigs, but it sure is nice to be climbing a hill with my foot on the floor and still barely be able to hear the engine. Plus it’s comforting knowing the engine is designed to run wide open with no ill effects.


All of that said, diesel does cost more to maintain, and if the noise thing isn’t an issue you’ll get more coach if you go gas. I would suggest test driving several gas and diesel coaches; you’ll soon know which is best for you.

[Gizmo]

It really all comes down to the right tool for the job.  If you plan to tow heavy and/or carry a lot of weight, particularly in the mountains, diesel wins hands down and is worth the added costs.  Diesels handle heavy loads considerably better and when travelling in the mountains two important benefits come into play, first diesels better handle steep grades under heavy loads and second diesels are not affected by altitude in terms of lost power, while gas engines tend to loose power the higher up in altitude you go, just when you need it.  They do however cost more to purchase and maintain.  On the other hand gas can be a good choice and there are some who do well with them..If you are not towing or carrying a heavy load, even in the mountains, though you may have to go it a bit slower in steep grades gas can do fine for you.

[Larry N.]

Diesels are quieter than gas. Diesels generally ride better due to air suspension. But you only spend on average 5% of your time driving an RV so I don't consider either one of these to be really big huge issues.

Diesels are quieter in the cab, it's true (for rear engine diesels), but can be noisier outside or in the interior rear. I spend a lot more than "5%" of my time driving (sometimes close to 40%) -- that's dependent on your travel pattern, but it's certainly necessary to be sure the floor plan is good for you. For long haul trips, even without mountains to climb, I find the diesel (DP) less wearing on me (and on DW) than a gas class A, so we're not as worn out at the end of the day. But it's not unusual for us to cover 300-400 miles in a day (often two or three days in a row), and folks who don't drive more than a couple hundred miles in a day will be less affected. So to me, diesel was a major factor, even discounting the mountains, especially since the much shorter rear overhang and the extra weight also mean better handling in gusty crosswinds or passing other large vehicles (semi, MH, etc.).

[JoelP]

Diesels cost more initially and are worth more when you go to sell it. A wash.

Diesels cost more to maintain but the engine lasts longer. A wash.

Diesels get better gas mileage but the gas is generally more expensive. A wash.

Financially I consider the diesel vs gas argument a complete wash.

Diesels are quieter than gas. Diesels generally ride better due to air suspension. But you only spend on average 5% of your time driving an RV so I don't consider either one of these to be really big huge issues.

Realistically I consider the diesel vs gas debate to be a question of the right tool for the right job. If you are doing a lot of mountain driving or towing a toad then a diesel is your best bet. Otherwise you are better off with a gasser.

I have owned both types and neither one seemed to have any advantage for me, they are just different. It is mainly an apples oranges comparison. A lot of men seem to think diesels are more macho but I think that is a horrible attitude.

I went for the gas plus a Banks for more torque, but I must say that the air suspension would be nice and there are features that one only see in a DP. An engine in the rear would make for a pleasant ride over the mountain passes.

[Oldgator73]

When we had a 5th wheel I pulled it with a 3/4 ton Dodge with the Cummins diesel. Cummins performed the maintenance on the motor. A mechanic at Cummins told me that motor liked high RPM. He told me as long as I kept up with the maintenance the motor should last a million miles. I don't know how many miles it lasted since we sold the 5th wheel and gave the truck to our son which he trashed. If I ever buy another big RV I would definitely buy another diesel truck.

[Gary RV_Wizard]

I mostly agree with Seilerbird, but the typical diesel pusher has a much more capable chassis than even the best gas-powered coach.  The rear diesel engine is only one part of the story. More weight carrying capacity, a smoother and better handling [sir] suspension, typically greater towing capacity, etc.

Diesels also produce their power at much lower rpms than gas engines, so diesel powered caches generally accelerate better & smoother, whether on hills or from a standing stop. And since diesels lack any inherent engine braking, they are usually equipped with an exhaust or engine brake system that retards speed more effectively than the throttle plate on a gas engine.

There is one more factor that can be hard to assess and varies by model: coach builders seldom put their best into a gas chassis rig.  Gas powered rigs  are targeted for a lower price range than any diesel pusher, so compromises get made in favor of lower price rather than better performance, handling, house quality, etc.

None of the above makes a gas chassis coach a poor choice, but all diesel pushers [except perhaps a the lowest entry level] will have at least some of the advantages mentioned here. The downside is always cost, up front and ongoing.

[timjet]

Something to keep in mind; Class A coaches under 35' are generally gas powered and those 40' and above generally diesel powered. There are exceptions of course but the decision on gas or diesel will generally only come into play when deciding on a coach in size ranges of 35 to 40 feet.

[Lou Schneider]

Diesel fuel itself is smelly and messy, it's almost identical to home heating oil.  It doesn't evaporate like gasoline does, so there will be an oily residue on fuel pump handles. Just touching the handle will make your hands smell like diesel fuel for the rest of the day unless you wear gloves while fueling.

Almost all diesel pumps have an oily mess on the concrete around them from the occasional spill, even just letting a couple of drops spill from the nozzle when transferring the hose from the vehicle back to the pump builds up over time.  You can generally tell which stations pump the most diesel, and so have the freshest fuel, by the amount of staining around the pumps.  This gets on the soles of your shoes and you'll track it into the RV if you enter it without changing your footwear.  Many long haul truck drivers carry two sets of shoes, work shoes to wear outside and slippers or other soft footwear to wear inside the truck to avoid tracking dirt and diesel into the cab.

Diesel engines cost several times more than gas engines to maintain.  Diesel creates soot when burned, this gets into the oil and contaminates it.  Diesel engines contain several times more oil than gassers to keep the soot under control between changes. Their fuel, air and oil filters are larger and more expensive, and maintenance has to be done by large truck shops.

If you buy a new diesel, you'll have to buy DEF (Diesel Exhaust Fluid) containing urea for the emission control system and keep that tank filled, too.

If your rig has air brakes, after sitting overnight or longer you'll have to idle the engine until the air pressure builds up to let you release the brakes and drive off.  Your neighbors will thank you if you're an early riser.

Just a few cons people don't think about when considering those sexy diesels.   

[TonyDtorch]

Don’t buy a crappy Rv because it has a Diesel engine. look for the best motor home.

Look for one with a good roof (fiberglass) and a good layout.   Whatever engine it has,  will get you anywhere you want to go.

I’ve seen people buy crappy low end diesel rigs,  just because it’s a diesel rig they could afford.

..on older rigs when that diesel radiator or that really cool air suspension plumbing and leveling switch gear starts leaking.... it starts getting expensive.

On a gas rig ...anyone can repair it and every Auto Zone has the parts.

[Isaac-1]

I am going to concentrate on a different point here, you say it is a nice RV with a diesel engine.  How do you know it is a nice RV?     Have you inspected it, do you  know the condition of the roof, have you made sure that it is not riding on a chassis with known design issues, like the trailing arms on the Roadmaster R4R's and RR4R's  or with one of the diesel engines that are known to be time bombs waiting to fail such as the issue with wrist pins in certain Cummins ISL diesels built between certain dates, ....

[WILDEBILL308]

I've never owned a Diesel in anything but have a chance to get a nice RV with a diesel from a neighbor. What are the pros and cons of a Diesel over a gas motorhome?

So many responses and so few understood you question and immediately went into their set spiel about gas versus diesel.
Please tell me what year, make and model you are looking at.
The major differences are the diesel will have the better built coach with better amenities, the ride is better and they are quieter.
One thing to check is the date code on the tires. You only run tires for 7 years gas or diesel. Ask about maintence records. Was the coach driven much or did it just sit?
I can give you better answers with more information.

[Utclmjmpr]

Tell us how you REALLY FEEL ABOUT DIESEL Lou.>>>Dan  (Spoken like a true gas man)

[Arch Hoagland]

A big advantage of a diesel is the fact that going DOWN mountains is easier. The compression of a diesel engine will hold back your RV whereas my gas engine doesn't hold it back hardly at all.

I go over mountains all the time and don't care if I'm slow going up, it's the braking technique I have to use going down the mountains that I dislike.

I'd love to have the large fuel tank that most diesels have. The less I have to go into gas stations the better I like it.

Your highest priority in purchasing an RV should be liking the layout. And keep in mind if Momma ain't happy...nobody is happy.

[Larry N.]

The compression of a diesel engine will hold back your RV whereas my gas engine doesn't hold it back hardly at all.

This statement is a bit misleading. Most diesels in RVs (and most big trucks) have an added engine brake that does the "hold back." Some are more effective than others -- my Beaver was much more effective than my Ventana, which is only a little better than a Bounder (gas) that I had. Without that add-on diesels are worse than a gas burner.

[Ernie n Tara]

You can use the truck pumps! Priceless!

Ernie

[TonyDtorch]

This statement is a bit misleading. Most diesels in RVs (and most big trucks) have an added engine brake that does the "hold back." Some are more effective than others -- my Beaver was much more effective than my Ventana, which is only a little better than a Bounder (gas) that I had. Without that add-on diesels are worse than a gas burner.

It's the difference between an exhaust brake, and a compression (Jake) brake. the Beaver had a Jake brake.

[kdbgoat]

And if getting a Ford gasser with a 2016 and up chassis, you get the six-speed transmission that has  a manual feature that essentially turns the transmission into a clutchless manual transmission.

[Tom]

Without one of the additional braking systems (such as engine/Jake brake, exhaust/Pac brake, or transmission retarder), a diesel has little or no braking, and the service brakes have to be used to slow/stop the vehicle. That would result in short life for the service brake components.

An engine brake works by effectively turning the engine into a compressor, releasing the compressed air (and energy) at the top of the compression cycle. See a fuller explanation on Jacobs' web site.

An exhaust brake works by electrically closing a flap in the exhaust system, creating back pressure to slow the vehicle.

As has been said, engine brakes are more effective in slowing a diesel than an exhaust brake. So much so, that some vehicles offer the driver several degrees of braking, which changes the number of cylinders used for braking.

[Oldgator73]

I had Cummins install an engine brake on our truck. They put it on the back cylinder. On the steepest grades out west I could put the truck in 3rd gear (5 speed) and engage the engine brake and never get over 30 mph and never engage the truck or trailer brakes. That was pulling a 37' triple slide triple axle 5th wheel.

[Tom]

Aye gator, when I've driven diesel coaches with multi-cylinder braking, I found myself reducing the number of cylinders.

FWIW when a CAT mechanic had the rocker covers off the big CATs in our boat (for maintenance), he explained the 3196 engines were both the same as used in over-the-road trucks at that time. He also showed me where they install the solenoids for engine brakes (not used on boats), and any combination or all six cylinders could have the brake solenoids installed.

[Oldgator73]

Most of you guys are smart on the mechanics  and Engineering of these things. All I know is I enjoyed the diesel truck. It powered up the steep grades with no problems and with the engine brake got us down the other side with ease. Now, mind you, this was back in the late 90's. Diesel was $.89 gal and this was before that DEF stuff was required for diesels. I just took the truck to Cummins when needed and got the required maintenance performed. Now, the Dodge truck it was in was a different story. The motor was built to last a million miles and the Dana 80 rear end contributed to the 3900lb CCC but the rest of the truck, the Dodge parts were basically crap.

[Larry N.]

It's the difference between an exhaust brake, and a compression (Jake) brake. the Beaver had a Jake brake.

I know, Tony. I guess I should have specified, but I was just trying to correct the impression that Arch left of the engine compression braking being an automatic thing just as it is on a gasser. Things work differently (and the Beaver was two stage, either three or six cylinders).

[Gary RV_Wizard]

What are the pros and cons of a Diesel over a gas motorhome?

Well, the diesel engine is part of it, but just one piece of "diesel pusher" vs a gas motorhome.

Diesels are used on larger/heavier rigs because it is the more effective way of moving big vehicles. Much has already been said here about engines and fuel, so I'll move on to the other aspects.

DP's have air brakes and air suspension. Air suspension is superior to leaf springs for ride comfort ans well as being auto-adjusting for changes in weight and weight distribution. Air braking has some technical advantages as well, so is the system of choice for very large & heavy vehicles.

A DP chassis is invariably designed to be more rigid and with greater weight capacity (GVWR & GCWR).  Some of that is because the diesel provides better low-rpm power, but some of it is simply that its a higher priced chassis that can bear the extra expense as part of the coach price (see below).  DP's enable the use of heavier components, e.g. real tile floors, solid wood cabinetry, larger appliances, bigger water tanks, etc.  Gas coaches max out at 22k-24k and 38 ft, so larger rigs with more amenities and upscale components are invariably diesel. You can have a few of the nice things in a gas rig, but you can't have them all because of weight and length considerations.

Because the diesel engine is so expensive, it pushes the coach into a higher price class. Thus, motorhome builders tend to put the other more expensive design attributes and components along with it.  There is a lower end to the  DP price scale, of course, but they generally still are better equipped than many gas chassis rigs. DPs generally start about where gas chassis coaches leave off.

[WILDEBILL308]

Well I wish the OP would come back and tell us what the coach is.
Bill

[Oldgator73]

WILDEBILL308
A man who carries a cat by the tail learns something he can learn in no other way.
-Mark Twain-

I learned my lesson with cats when I tried to take ours in the shower with me. Took the wife a good while to extricate the cate from my chest.

[timjet]

As Gary above has said, a DP is more than the engine. It was the other things that swung the decision for me to buy my DP. But the very reliable and often used Cummins ISL didn't hurt either.

[Gary RV_Wizard]

Putting it another way, a typical diesel pusher is a bundle (package) of enhanced chassis capabilities and house upgrades.

If the discussion is solely about engines, then the proper comparison would be something like Freightliner FRED or Workhorse front diesel vs the Ford or Workhorse front gas chassis.  Those are substantially the same except for the engine and are used to carry substantially the same size & equipped body (house). The Tiffin Allegro Open Road, for example, was available with either front gas or front diesel power, so an apples-to-apples comparison can be made.  The front diesel version has an increased GVWR (carrying capacity), gets slightly better mpg, and accelerates well without requiring high (noisy) engine rpms.