Diesel vs. Gas Longevity?
#16
09-16-2018, 10:43 PM
Posting Guru
I always intend to keep my trucks forever but it never works out that way. My last one made it 14 years before it started to nickel and dime me with small repairs. Got rid of it and have a new 6.2 that I intend to keep forever so we’ll see exactly how long “forever” is this time!
right! This is the problem. The engines will be fine if properly cared for but the nickel and dime stuff around it will agitate you. Had our Honda CRV for 14 years. The engine gave us no issues. The alternator and drive shaft both went. Obviously with that kind of mileage you’ll be having to replace shocks and brakes etc.... but with that amount of time other things get old seats and just the interior in general. Our 15 year old Mercedes still under 100k but needs shocks and has small rust forming everywhere. Not worth fixing.
#17
09-17-2018, 06:56 AM
Hotshot
The old way of thinking, that a diesel will far outlast a gas engine is just that...an old way of thinking. Emissions have killed the "diesel longevity" argument.
I would never, ever want to own a modern diesel engine out of warranty. There are way too many very expensive emissions components, fuel system components, and exhaust components that a lot of people couldn't afford to replace on their own.
I would never, ever want to own a modern diesel engine out of warranty. There are way too many very expensive emissions components, fuel system components, and exhaust components that a lot of people couldn't afford to replace on their own.
#18
09-17-2018, 07:47 AM
If the diesel lasts for 500k miles while a gas engine has to be replaced at 250k miles, but the diesel had to have a set of injectors and pump that costs more than a new gas engine, then have you really saved anything? Just mentioning the fact that that a few repairs to a modern diesel engine can easily cost more than a engine replacement for a gas truck. Something else for the OP to think about.
#19
09-17-2018, 07:56 AM
Some fleets are going with gas, but from what I have seen it's because the problems of operators using the wrong fuels and doing major damage. Most u haul type trucks will all be gas. Too meny people where filling the diesel tanks with gas and driving off till the engine dies.causing major damage.
#21
09-17-2018, 10:17 AM
Hotshot
...If you look at engine hp and torque output between the gas and diesel engines you will find the max output for gas engines will be at more than twice the RPMs of a Diesel engine.
So if the gas engine is used in an application of heavy use, the engine will have to turn twice the speed of the Diesel to get the needed power
So, you have two equal trucks, one gas one Diesel, heavily loaded, so close to max output is needed, the gas engine could have twice the number of revolutions as the diesel. That means the possibility of twice the wear.
Now look at the engine oil, and cooling system capacities. What set up do you think is more capible to handle max loads?
There is a reason that class 8 trucks are almost all Diesel, it's the most economical way to haul heavy loads, this is a place where every penny counts.
If gas engines where cheaper to run they would be using them.
So if the gas engine is used in an application of heavy use, the engine will have to turn twice the speed of the Diesel to get the needed power
So, you have two equal trucks, one gas one Diesel, heavily loaded, so close to max output is needed, the gas engine could have twice the number of revolutions as the diesel. That means the possibility of twice the wear.
Now look at the engine oil, and cooling system capacities. What set up do you think is more capible to handle max loads?
There is a reason that class 8 trucks are almost all Diesel, it's the most economical way to haul heavy loads, this is a place where every penny counts.
If gas engines where cheaper to run they would be using them.
To the OP - in my opinion, neither engine is going to make it to 4-500k miles. While possible, it's unlikely. Most high mileage engines are in young bodies and just get driven a lot. Time takes it's toll as much as mileage. Does anyone here really think a 20 year old 6.7L with 500k miles on it will still have the original high pressure fuel pump? Because that's like $9k to replace when it grenades, and might not make sense to do on an old truck. I doubt the original injectors will last either.
The gas is the better proposition for you, in my opinion.
#22
09-17-2018, 10:47 AM
#24
09-17-2018, 10:54 AM
Most fleets have changed to gas because of the cheaper purchase cost, the cheaper maintenance costs, and the less time in the shop that gas trucks provide. My V10 powered work truck has 173,000 miles and 9,500 hours on it and the only engine related repairs has been a set of spark plugs and two coil packs.
The cost is extreme for fleets trust me! Having swapped the majority of our trucks to gas the repairs are lower, more linear and predictable. The lower MPG is offset completely the entire life of the vehicle simply with lower upfront and lower service costs add in to that lower component cost and it's a win. We can swap a blown v10 for what a fuel system refresh on a 6.7 costs.
The exception to the diesel's in our fleet is about 55 F750 derrick trucks and those have been hit and miss so far. Lots of driver error and prolonged idling issues that have resulted in some expensive repairs. The DEF on a medium duty truck is nearly 3500k and sometimes they can't be baked out and have to be swapped. I will say however the gas engines only sound new for the first 60k in our fleet, the diesel engines sound the same until they die. Anyone that has been around fleet trucks will know the sound.
#29
09-17-2018, 09:45 PM
Cargo Master
I've owned several of every Powerstroke since 1999. I just got rid of a 2017 6.7L. I've only logged about 3 million miles with mostly diesels, so maybe I'm green, but at this time, and probably forever from here, I too will never own a diesel out of warranty unless the EGR and DPF are pulled off before 10k when new. The oil alone tells the story. Untweaked, your fingers that touch the drain oil stay black for days. Tweaked, you can see through it at 5,000 mikes. My experience, the new emissions have spoiled all the fun. I was fed up driving to run a regeneration out to completion.
When I bought my last 2017 F250, I almost went 6.2L, but I was so used to diesels, I thought I'd regret it. I ran spreadsheets after spreadsheets, and unless you tow significant weight, the gasser will be cheaper in the long run. I knew I'd dump mine before 100k, so the money spent on the diesel would return, but as a daily driver of only 25k, the OP should IMO reconsider NOT going diesel. I would second guess any new untweaked diesel going 300k without some pricey repairs, and even if the 6.2L died at 300k, it's an easier replacement or repair.. With the price of trucks today, I'd be looking for the longest lasting, too, but I still get nailed for high mileage each year, so I trade more often as I have a good friend who owns a dealer and it's been fair. I'm in the same boat now, thinking about buying something to run to 200k, but even the 2018 F150 I have now seems like a stretch for 200k with issues I'm having. The 6.2L and 6-speed seem tried and true. That may be my next bet.
When I bought my last 2017 F250, I almost went 6.2L, but I was so used to diesels, I thought I'd regret it. I ran spreadsheets after spreadsheets, and unless you tow significant weight, the gasser will be cheaper in the long run. I knew I'd dump mine before 100k, so the money spent on the diesel would return, but as a daily driver of only 25k, the OP should IMO reconsider NOT going diesel. I would second guess any new untweaked diesel going 300k without some pricey repairs, and even if the 6.2L died at 300k, it's an easier replacement or repair.. With the price of trucks today, I'd be looking for the longest lasting, too, but I still get nailed for high mileage each year, so I trade more often as I have a good friend who owns a dealer and it's been fair. I'm in the same boat now, thinking about buying something to run to 200k, but even the 2018 F150 I have now seems like a stretch for 200k with issues I'm having. The 6.2L and 6-speed seem tried and true. That may be my next bet.
#30
09-17-2018, 10:07 PM
I kept my last truck 20 yrs and 265K miles. I looked at gas and diesel on the F250 and decided on gas. I calculated with my driving and fuel mileage from each engine that it would take me 23 years to pay off the diesel upgrade. In 23yrs I'll be 75 yrs old and probably wont be able to get in the truck anymore.