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The RVer's Open Forum / GENERAL RV DISCUSSIONS / diesel vs gas

Next 20 Messages

Dean
User ID: 9704903 Sep 6th 2:22 AM
Do diesel engines have a longer lifespan than gas? Is there any downside to a diesel other than higher initial cost?

KOG
User ID: 0081374 Sep 6th 4:04 AM
Medium duty engines last longer than light duty engines. Heavy duty engines last longer than medium duty engines. Most diesels used in MHs are medium duty truck engines. Gas engines are mostly light duty units. There are some significant exceptions to this rule some of the diesel used in P/Us in the past have been rather light duty and some of those used in cars now are light duty.

Yes, there are other differences between gas and diesel engines other than durability that don't exactly favor diesels. For any given power output a diesle tends to be heavier, noisier, requires more frequent oil changes (for the small units we're talking about in MHs) and can have routine maintenance cost higher than a gas engine. Diesels are much rougher on transmissions because of their firing characteristics. They can be difficult to start in cold weather (or not, depending on how effective their various heating devices are). They tend to require much larger batteries and starters. Overhaul costs are much higher than gas.

Bottom line is that diesels pay off for users who run high annual mileage or who have power needs that can't be met by commonly available gas engines. Another factor to consider is that mdeium duty engines tend to be rated for continuous power output whereas light duty engines are rated at peak power outputs that they cannot sustain for more than very short periods of time. That means that comparing HP ratings of light duty gas engines to those of medium duty diesels is apples and oranges. A 250HP rating on a diesel can easily be equivalent to a 300-350 HP rating on a gas engine in terms of continuous output.

Kirk
User ID: 8318753 Sep 7th 10:09 AM
I am going to disagree just a little with KOG. Modern motorhomes do not have light duty engines. Medium duty would be more accurate. What the gas chassis motorhomes have is a beefed up version of the engines found in small to medium trucks. They have a life that should make 150K miles with proper maintenance. The diesels have engines of similar size, but higher torque, as all diesels do. And they have a life that is probably twice as long, with proper maintenance. If price is not a factor, then the diesel is a better choice, but not just for the engine if you are looking at motorhomes. In them, diesels usually have an air ride system, and most will have a better caro capacity, though not all. And now that the diesel is coming into the lower priced motorhomes, there are also smaller and shorter lived diesel engins that do not have the six speed transmission that the better ones have.

This is not a simple question. For most of us, a gas powered RV will do the job quite well, if the question is one of budget. Another downside to the diesels is the fact that maintenance is much more costly, praticularly in motorhomes. And for us the stinking exhaust is also a negitive as my wife has a violent reaction to it due to her asthma and allergies.

Good travelin!..............Kirk
URL: www.1tree.net/adventure/

KOG
User ID: 0081374 Sep 7th 10:15 AM
And I'll have to disagree just a little with Kirk. The gas engines found in MH chassis are identical to those used in 3/4 and 1T P/Us. Every thing else he said, including the at least 150,000 mile life for well kept gas engines, I agree with. That aplies to current gas engines. The 454 and 460 engines used in older MHs won't necessarily last as long as the current more powerful gas engines. I'm looking at diesels for the other reasons he mentioned - air ride, 6 speed transmissions as well as lower noise both driving and camping.

Barthbill
User ID: 7984023 Sep 7th 11:53 AM
Another advantage of the better DPs is that they come with a better chassis, by far. Gas coaches usually are on a "bread van" chassis that leave a lot to be desired in handling (read safety) and load caqpacity. Some of the DPs are a dream to drive. The curvier the road, the better they feel (the greater the margin of safety) with a DP.
And the better DPs have MUCH better basement storage.
KOG, how does a DP have lower noise while camping?

Chris Fine
User ID: 9433023 Sep 7th 12:17 PM
Some more reasons to buy newer gas rigs would be; overdrive transmissions. Older gas units had direct drive transmissions. That means the engine speeds per mile are pretty high. The more revs.per mile, the less life. An OD trans slows down the RevsPM, the longer the motor lasts! Next is fuel injection. Carbs just do not adjust gas/air mixtures very well. They do not compensate for altitude, air density, and general mixture. FI does. Lean conditions = burned internals and rich = washing cylinder walls causing premature wear. Finally modern metalurgy (sp?) gets better every year. Better metal = more life! I guess all my spouting means, if you want gas, buy newer !!

KOG
User ID: 0081374 Sep 7th 1:08 PM
DPs a are quieter camping in the bedroom because the generators are usually mounted in the nose instead of under the bed.

Barthbill
User ID: 7984023 Sep 7th 1:21 PM
Oh, yeah, that's right. Recently we walked by a DP which had a Generac buried somewhere in front. All we could hear was a mild rushing of air out the exhaust. I was AMAZED. I asked if it was water cooled but the owner didn't know.

tk
User ID: 9892733 Oct 4th 7:38 PM
Something not mentioned for those that can go either way: Diesels have WAY more pollution out the exhaust than gas engines. If I recall the article, the reason is less complete combustion, which is why you can smell 'em some distance away.
The no arguement advantages of diesels are more power/torque at lower RPMS & longevity (how many of us keep our rigs 20 years?), and the disadvantages are higher initial & annual maintenance costs, and smell & noise for some of us.

RichB
User ID: 8897163 Oct 4th 8:28 PM
tk,

I'd really like to see that article. I know that you see more particulants (sp?) in the exhaust, but that is partially do to the refineing process. Diesel fuel isn't as highly refined as gasoline is.

By the same token.... I've heard rumors that in the next couple of years the emmissions from diesels is going to be reduced by higher refining of the fuel, and a "more efficient" engine that is being developed.

I know there is a company in Woodland Park, CO that is working to develop a more efficient diesel engine. They were on the local news tonight, but off hand I can't recall the name.

Joe
User ID: 9523443 Oct 9th 2:03 PM
If your thinking of buying a gas or diesel Motor home, I can only say, do what everyone told me. "If your buying a gas rig now you will be buying a diesel later. Go ahead and buy the diesel and avoid having to move up later. And one other note. Buy pre-owned. You save a ton of money and avoid all the little warranty items that have been taken care of.

tk
User ID: 9892733 Oct 18th 10:19 AM
Good arguements, New Guy! Unfortunately, I didn't save the news article I read on the higher pollution due to diesel engines, and don't recall which pollution chemical(s) it was referring to either. Notice that my thread above started by saying for those that can go either way! I pull a small TT, and don't need the higher torque of diesel, nor do I care for the noise & smell.

I agree that the more weight/bigger rig one has, that the torque advantages of diesel make a difference. I'm a happy camper staying small, as my primary goal is to CAMP in the rig, not LIVE in the rig.

FWIW, just talked to a guy yesterday that used to NOT like diesels either, and he recently obtained his son's powerstroke, and now LOVES diesels. Says he can fly up the mountain grades in Oregon at any speed he wants pulling a small 24ft. TT. That would be a new experience for me also!

brad parker
User ID: 0854544 Oct 18th 9:49 PM
I don't know if i missed it but one thing for sure is better mileage with a diesel over a gas..

My 97chev 1T dually 454 vortec 5 mpg towing a 27'5er and boat. 9-10mpg empty.

New 2002 powerstroke Ford F350 dually same configuration 17mpg...22empty

Al
User ID: 1781064 Nov 26th 6:08 PM
Get a diesel Dont make the mistake that I did. Buy a gas and then trade it 4 months later.

Ed
User ID: 8277173 Nov 27th 8:15 AM
All you hear about a diesel is more power and torque. Which is nice but it is not free. While I'm not an engineer I believe that the more torque you have the more stress and strain there is on the transmission, drive line parts and the rear end. Not to mention the extra wear on the tires. Back in the '50s when I started trucking about 1/2 of the over the road tucks were gassers and I never saw one stlalled on a mountain. Slow, yes but they got the job done. So which is more important in a M/H, the motor or the home? Like I said before, buy what you can afford and have fun. Ed

Jim S.
User ID: 8973393 Nov 27th 11:01 AM
Guess my take on the gas vs. diesel engine debate is a somewhat different than most, when it applies to motorhomes. I consider a motorhome a place to live and the engine, be it gas or diesel, just a means to move our living quarters from one place to another. Both engines will do that, granted, if the ride is critical to the owner along with the ability to cruise up steep grades at 55 to 65mph as opposed to 35 to 50mph, then by all means buy a diesel pusher. Our priority is focused more on the living aspect of the motorhome as opposed to power and ride. Our gas rig has an acceptable quality of ride for us, and sure, more power for the steep grades would be nice, but we always make it over the hump, perhaps a bit slower, but we accepted that trade-off. Would we like to have a diesel pusher, of course, but not willing to pay the price, and quite frankly we haven't seen one with an interior and floor plan layout we like as well as the one in our rig.

Best Regards, and wishing all safe and happy Holidays

Jim S.

Kimcar
User ID: 2386864 Nov 27th 8:40 PM
Exhaust Brake! Going down hill you can relax and hold at a reasonable speed with out over using the brakes.

Marty
User ID: 0408214 Dec 9th 7:21 PM
Kevin, I can answer your question. For me, to put it into a mathematical equation, it's called "cost verse utilization over income equals owernership." So my "gasser" do me just fine.

Marty in TN

kevin
User ID: 2261164 Dec 11th 3:53 PM
Looking at the cost per mile in your utilization equation would put a 15mpg diesel at 1.43 per gallon versus a 8 mpg gasser at 1.53 per gallon. The cost per mile for a diesel is 9.5 per mile and the gasser is 19.1 per mile. The engine upgrade is about 4k for the Ford PSD 7.3, so 40,000 miles is breakeven. The next 210,000 is bonus.

gmachine
User ID: 1265504 Dec 11th 6:01 PM
For what it's worth!
Have owned 4 ISB D***E Quad Cabs & now a REAL TRUCK(also ISB), and would never buy anything but diesel, however, gas is probably best for the average RV'er.(1) Service & parts availability for those who can't or don't care to do their maintenance &(2)gas is readily available almost anywhere & lately is cheaper than #2 truck fuel. Another point though, unless the intent is to keep the unit untill it dies, the extra premium for diesel at original purchase is not as significant as purported; the trade-in value is much higher for the diesel trucks.
Good Luck with whatever you choose, Jim.

Next 20 Messages

Dean User ID: 9704903	Sep 6th 2:22 AM Do diesel engines have a longer lifespan than gas? Is there any downside to a diesel other than higher initial cost?
KOG User ID: 0081374	Sep 6th 4:04 AM Medium duty engines last longer than light duty engines. Heavy duty engines last longer than medium duty engines. Most diesels used in MHs are medium duty truck engines. Gas engines are mostly light duty units. There are some significant exceptions to this rule some of the diesel used in P/Us in the past have been rather light duty and some of those used in cars now are light duty. Yes, there are other differences between gas and diesel engines other than durability that don't exactly favor diesels. For any given power output a diesle tends to be heavier, noisier, requires more frequent oil changes (for the small units we're talking about in MHs) and can have routine maintenance cost higher than a gas engine. Diesels are much rougher on transmissions because of their firing characteristics. They can be difficult to start in cold weather (or not, depending on how effective their various heating devices are). They tend to require much larger batteries and starters. Overhaul costs are much higher than gas. Bottom line is that diesels pay off for users who run high annual mileage or who have power needs that can't be met by commonly available gas engines. Another factor to consider is that mdeium duty engines tend to be rated for continuous power output whereas light duty engines are rated at peak power outputs that they cannot sustain for more than very short periods of time. That means that comparing HP ratings of light duty gas engines to those of medium duty diesels is apples and oranges. A 250HP rating on a diesel can easily be equivalent to a 300-350 HP rating on a gas engine in terms of continuous output.
Kirk User ID: 8318753	Sep 7th 10:09 AM I am going to disagree just a little with KOG. Modern motorhomes do not have light duty engines. Medium duty would be more accurate. What the gas chassis motorhomes have is a beefed up version of the engines found in small to medium trucks. They have a life that should make 150K miles with proper maintenance. The diesels have engines of similar size, but higher torque, as all diesels do. And they have a life that is probably twice as long, with proper maintenance. If price is not a factor, then the diesel is a better choice, but not just for the engine if you are looking at motorhomes. In them, diesels usually have an air ride system, and most will have a better caro capacity, though not all. And now that the diesel is coming into the lower priced motorhomes, there are also smaller and shorter lived diesel engins that do not have the six speed transmission that the better ones have. This is not a simple question. For most of us, a gas powered RV will do the job quite well, if the question is one of budget. Another downside to the diesels is the fact that maintenance is much more costly, praticularly in motorhomes. And for us the stinking exhaust is also a negitive as my wife has a violent reaction to it due to her asthma and allergies. Good travelin!..............Kirk URL: www.1tree.net/adventure/
KOG User ID: 0081374	Sep 7th 10:15 AM And I'll have to disagree just a little with Kirk. The gas engines found in MH chassis are identical to those used in 3/4 and 1T P/Us. Every thing else he said, including the at least 150,000 mile life for well kept gas engines, I agree with. That aplies to current gas engines. The 454 and 460 engines used in older MHs won't necessarily last as long as the current more powerful gas engines. I'm looking at diesels for the other reasons he mentioned - air ride, 6 speed transmissions as well as lower noise both driving and camping.
Barthbill User ID: 7984023	Sep 7th 11:53 AM Another advantage of the better DPs is that they come with a better chassis, by far. Gas coaches usually are on a "bread van" chassis that leave a lot to be desired in handling (read safety) and load caqpacity. Some of the DPs are a dream to drive. The curvier the road, the better they feel (the greater the margin of safety) with a DP. And the better DPs have MUCH better basement storage. KOG, how does a DP have lower noise while camping?
Chris Fine User ID: 9433023	Sep 7th 12:17 PM Some more reasons to buy newer gas rigs would be; overdrive transmissions. Older gas units had direct drive transmissions. That means the engine speeds per mile are pretty high. The more revs.per mile, the less life. An OD trans slows down the RevsPM, the longer the motor lasts! Next is fuel injection. Carbs just do not adjust gas/air mixtures very well. They do not compensate for altitude, air density, and general mixture. FI does. Lean conditions = burned internals and rich = washing cylinder walls causing premature wear. Finally modern metalurgy (sp?) gets better every year. Better metal = more life! I guess all my spouting means, if you want gas, buy newer !!
KOG User ID: 0081374	Sep 7th 1:08 PM DPs a are quieter camping in the bedroom because the generators are usually mounted in the nose instead of under the bed.
Barthbill User ID: 7984023	Sep 7th 1:21 PM Oh, yeah, that's right. Recently we walked by a DP which had a Generac buried somewhere in front. All we could hear was a mild rushing of air out the exhaust. I was AMAZED. I asked if it was water cooled but the owner didn't know.
tk User ID: 9892733	Oct 4th 7:38 PM Something not mentioned for those that can go either way: Diesels have WAY more pollution out the exhaust than gas engines. If I recall the article, the reason is less complete combustion, which is why you can smell 'em some distance away. The no arguement advantages of diesels are more power/torque at lower RPMS & longevity (how many of us keep our rigs 20 years?), and the disadvantages are higher initial & annual maintenance costs, and smell & noise for some of us.
RichB User ID: 8897163	Oct 4th 8:28 PM tk, I'd really like to see that article. I know that you see more particulants (sp?) in the exhaust, but that is partially do to the refineing process. Diesel fuel isn't as highly refined as gasoline is. By the same token.... I've heard rumors that in the next couple of years the emmissions from diesels is going to be reduced by higher refining of the fuel, and a "more efficient" engine that is being developed. I know there is a company in Woodland Park, CO that is working to develop a more efficient diesel engine. They were on the local news tonight, but off hand I can't recall the name.
Joe User ID: 9523443	Oct 9th 2:03 PM If your thinking of buying a gas or diesel Motor home, I can only say, do what everyone told me. "If your buying a gas rig now you will be buying a diesel later. Go ahead and buy the diesel and avoid having to move up later. And one other note. Buy pre-owned. You save a ton of money and avoid all the little warranty items that have been taken care of.
tk User ID: 9892733	Oct 18th 10:19 AM Good arguements, New Guy! Unfortunately, I didn't save the news article I read on the higher pollution due to diesel engines, and don't recall which pollution chemical(s) it was referring to either. Notice that my thread above started by saying for those that can go either way! I pull a small TT, and don't need the higher torque of diesel, nor do I care for the noise & smell. I agree that the more weight/bigger rig one has, that the torque advantages of diesel make a difference. I'm a happy camper staying small, as my primary goal is to CAMP in the rig, not LIVE in the rig. FWIW, just talked to a guy yesterday that used to NOT like diesels either, and he recently obtained his son's powerstroke, and now LOVES diesels. Says he can fly up the mountain grades in Oregon at any speed he wants pulling a small 24ft. TT. That would be a new experience for me also!
brad parker User ID: 0854544	Oct 18th 9:49 PM I don't know if i missed it but one thing for sure is better mileage with a diesel over a gas.. My 97chev 1T dually 454 vortec 5 mpg towing a 27'5er and boat. 9-10mpg empty. New 2002 powerstroke Ford F350 dually same configuration 17mpg...22empty
Al User ID: 1781064	Nov 26th 6:08 PM Get a diesel Dont make the mistake that I did. Buy a gas and then trade it 4 months later.
Ed User ID: 8277173	Nov 27th 8:15 AM All you hear about a diesel is more power and torque. Which is nice but it is not free. While I'm not an engineer I believe that the more torque you have the more stress and strain there is on the transmission, drive line parts and the rear end. Not to mention the extra wear on the tires. Back in the '50s when I started trucking about 1/2 of the over the road tucks were gassers and I never saw one stlalled on a mountain. Slow, yes but they got the job done. So which is more important in a M/H, the motor or the home? Like I said before, buy what you can afford and have fun. Ed
Jim S. User ID: 8973393	Nov 27th 11:01 AM Guess my take on the gas vs. diesel engine debate is a somewhat different than most, when it applies to motorhomes. I consider a motorhome a place to live and the engine, be it gas or diesel, just a means to move our living quarters from one place to another. Both engines will do that, granted, if the ride is critical to the owner along with the ability to cruise up steep grades at 55 to 65mph as opposed to 35 to 50mph, then by all means buy a diesel pusher. Our priority is focused more on the living aspect of the motorhome as opposed to power and ride. Our gas rig has an acceptable quality of ride for us, and sure, more power for the steep grades would be nice, but we always make it over the hump, perhaps a bit slower, but we accepted that trade-off. Would we like to have a diesel pusher, of course, but not willing to pay the price, and quite frankly we haven't seen one with an interior and floor plan layout we like as well as the one in our rig. Best Regards, and wishing all safe and happy Holidays Jim S.
Kimcar User ID: 2386864	Nov 27th 8:40 PM Exhaust Brake! Going down hill you can relax and hold at a reasonable speed with out over using the brakes.
Marty User ID: 0408214	Dec 9th 7:21 PM Kevin, I can answer your question. For me, to put it into a mathematical equation, it's called "cost verse utilization over income equals owernership." So my "gasser" do me just fine. Marty in TN
kevin User ID: 2261164	Dec 11th 3:53 PM Looking at the cost per mile in your utilization equation would put a 15mpg diesel at 1.43 per gallon versus a 8 mpg gasser at 1.53 per gallon. The cost per mile for a diesel is 9.5 per mile and the gasser is 19.1 per mile. The engine upgrade is about 4k for the Ford PSD 7.3, so 40,000 miles is breakeven. The next 210,000 is bonus.
gmachine User ID: 1265504	Dec 11th 6:01 PM For what it's worth! Have owned 4 ISB D***E Quad Cabs & now a REAL TRUCK(also ISB), and would never buy anything but diesel, however, gas is probably best for the average RV'er.(1) Service & parts availability for those who can't or don't care to do their maintenance &(2)gas is readily available almost anywhere & lately is cheaper than #2 truck fuel. Another point though, unless the intent is to keep the unit untill it dies, the extra premium for diesel at original purchase is not as significant as purported; the trade-in value is much higher for the diesel trucks. Good Luck with whatever you choose, Jim.