Fuelly mileage of the big three diesels

32vld wrote:


Spending $5,000 more plus the added interest on the higher overall price for a diesel
to sell a vehicle for $5,000 more minus the added interest leaves one with getting
less than $5,000 back at resale.

spending more so sell for more 10 years later, incurring higher interest charges
is not smart financial planning.

I said more than $5,000 because you generally receive roughly 60-80% of what you paid for an upgrade back in resale. This goes for any option like the $10-11k high trim options, $3k on a 4wd option, $2.5k crew cab option, or even $2.5k going from the base gas engine to a premium gas engine. However, you never fully recoup that money spent on these options at resale and in some cases ,like 4wd and premium gas engine options, you end up spending more over the life of the vehicle due to lower fuel mileage and higher maintenance costs.

With diesels, you not only recoup 60-80% of the upfront costs like all the other options, but you also recoup it in fuel mileage as well. So unlike those premium gas engine options that cost $3-4k over the base engines and even more in the long run, with a diesel you get more power and most if not all of the up front cost will be paid back through fuel mileage if you keep it long enough or through fuel mileage and resale if you don't.

ShinerBock wrote:

32vld wrote:



Comparing apples to oranges.


Numbers for an example:

Base model pickup $25,000 gas, $35,000 diesel option

Mid model pickup $35,000 gas, $45,000 diesel option

Top model pickup $45,000 gas, $55,000 diesel option


The base model truck is not a better truck with a diesel then
the mid model truck because it still has less features.

Three identical mid model pickup trucks, one has a 4.8 V6, another a 5.3 V8,
one with a 6.0 V8. None of them is the best. Depending what someone
values/needs such as purchase price, fuel economy, power, is what
makes that truck perfect for them.

I did the math many years ago when a diesel option would cost $5,000.
If you drive a diesel pickup 100,000 miles a year in one year it would
pay back that $5,000 higher purchase price based on better mpg even
with higher fuel costs

If you drove that same truck 10,000 miles a year it would take 10 years
to pay back that $5,000 higher purchase price based on better mpg even
with higher fuel costs.

Though those numbers did not include higher diesel maintenance and
repair costs.

Then there is the high wear and tear from high mileage and the high
wear and tear from age.

You bought the diesel, used it 10,000 miles a year. It's now 10 years old with 100,000
miles. The AC stopped working, the power seats are broken, interior worn,
seat fabric has some splits, tears, power door locks some times work, LF power
window won't go down. Fender has a ding, Got some rust starting. Truck
developed rattles (must be a Ford) creaks ad clunks (must be a Dodge)

Now what would be better to keep that 10 year old truck because it as just past
the break even point for buying a diesel. Or to of not spent that $10,000 on
the diesel option back then but use that $10,000 now as a down payment on
a brand new pickup (Chevrolet)?

And when you traded that truck in, you would get over $5,000 more for it than you would the gas option. Just like the Lariat/Laramie trim has a higher resale value than an XL/Tradesman option and you get most of that money spent up front back. Would the Lariat/Laramie trim save you money in fuel along with the a higher resale like a diesel would?

Spending $5,000 more plus the added interest on the higher overall price for a diesel
to sell a vehicle for $5,000 more minus the added interest leaves one with getting
less than $5,000 back at resale.

spending more so sell for more 10 years later, incurring higher interest charges
is not smart financial planning.

Dadoffourgirls wrote:

I was towing between MI and Kansas. 10 mpg. I purchased the Def at the truck pumps at $2.99, and most have used slightly more than your calculation. I was surprised by the amount of DEF I used, but followed the messages.

Well then of course. The cost per mile of DEF/diesel will go up when towing just as it would with a gas truck. My calculations are based on average fuel economy numbers on Fuelly. However, if you have a GM diesel, then you likely use more DEF simply because they get the worst fuel mileage of all three according to the Fuelly images in my initial post. The more fuel the truck uses, the more DEF it uses.


Doing the math at 10 mpg, your DEF usage should be $.00598 per mile at the industry standard of 50:1.

ShinerBock wrote:

Dadoffourgirls wrote:

ShinerBock wrote:
... DEF adds an additional $.001-$.002 to the diesel cost per mile on fuel so it is really a non-issue.

I disagree on DEF cost. My trip to Kansas and back was $.0075 - much closer to a real penny than your data.

Were you towing? If not, then you either use way to much DEF(and have an underlying issue), get horrible fuel mileage, or paid way to much for a gallon of DEF.

The standard usage for DEF is between 50 to 1 and 60 to 1 meaning one gallon of DEF for every 50-60 gallon of diesel should be used if the system is operating correctly. Round trip from Michigan to Kansas is roughly 2,000 miles. If you got 18 mpg on the highway, then that would mean you used 111 gallons of diesel. Divide that by 50 and you get 2.22 gallons of DEF used the whole trip. At $2.97 per gallon at the pump, that would come out to $6.60 for DEF over the course of 2,000 miles. Divide $6.60 by 2,000 miles and you get $.0033 cents per mile.

I haven't needed DEF since 2016 and that was the last time I checked prices. So while I am a little short with my $.001-.002, I am not that far off and it is still not enough to make much of a difference. If the reason why yours is much higher because you are paying the $12-15$ for the 2.5 gallon DEF jug($4.80- $6.00 per gallon), then that is user error for paying too much for old DEF.

There is a Love's the next town over from you that sells DEF for $2.97 at the pump.

I was towing between MI and Kansas. 10 mpg. I purchased the Def at the truck pumps at $2.99, and most have used slightly more than your calculation. I was surprised by the amount of DEF I used, but followed the messages.

Dadoffourgirls wrote:

ShinerBock wrote:
... DEF adds an additional $.001-$.002 to the diesel cost per mile on fuel so it is really a non-issue.

I disagree on DEF cost. My trip to Kansas and back was $.0075 - much closer to a real penny than your data.

Were you towing? If not, then you either use way to much DEF(and have an underlying issue), get horrible fuel mileage, or paid way to much for a gallon of DEF.

The standard usage for DEF is between 50 to 1 and 60 to 1 meaning one gallon of DEF for every 50-60 gallon of diesel should be used if the system is operating correctly. Round trip from Michigan to Kansas is roughly 2,000 miles. If you got 18 mpg on the highway, then that would mean you used 111 gallons of diesel. Divide that by 50 and you get 2.22 gallons of DEF used the whole trip. At $2.97 per gallon at the pump, that would come out to $6.60 for DEF over the course of 2,000 miles. Divide $6.60 by 2,000 miles and you get $.0033 cents per mile.

I haven't needed DEF since 2016 and that was the last time I checked prices. So while I am a little short with my $.001-.002, I am not that far off and it is still not enough to make much of a difference. If the reason why yours is much higher because you are paying the $12-15$ for the 2.5 gallon DEF jug($4.80- $6.00 per gallon), then that is user error for paying too much for old DEF.

There is a Love's the next town over from you that sells DEF for $2.97 at the pump.

ShinerBock wrote:
... DEF adds an additional $.001-$.002 to the diesel cost per mile on fuel so it is really a non-issue.

I disagree on DEF cost. My trip to Kansas and back was $.0075 - much closer to a real penny than your data.

"2 brake jobs have been the repairs to date."

You must never use your Exhaust Brake running BobTail.

those numbers are terrible.
Diesels need air in and air out. Change out air intake and add 4 inch exhaust. Then maybe a mild tune designed for towing to advance the timing slightly.
My F-350 gets well over 20 mpg, as much as 23.8 using cruise control.
Those numbers are just the starting point.

According to todays AAA state average fuel prices, these are the differences between diesel and regular octane below. Negative numbers means diesel is below the cost of gas.

Keep in mind that with an average combined fuel mileage disparity(according to Fuelly) of diesel and gas HD trucks, there has to be a difference of over $.55 cents for gas HD trucks to have a lower cost per mile than than diesel HD trucks.

At $2.00 per gallon, a gas HD truck that averages 12 mph combined has a cost per mile of $.17 cents. At the same $2.00 per gallon, a diesel HD truck that averages 15 mpg combined has a cost per mile of $.13 cents. Diesel would have to be at $2.55 for it to have the same $.17 cent cost per mile as the gas version. DEF adds an additional $.001-$.002 to the diesel cost per mile on fuel so it is really a non-issue.

State  DIFF
Alaska : -$0.11
Washington : -$0.09
Colorado : -$0.08
Nevada : -$0.05
Utah : -$0.05
Idaho : -$0.04
Oregon : [COLOR=]-$0.03
Montana : $0.00
Nebraska : $0.07
North Dakota : $0.07
Illinois : $0.08
Wisconsin : $0.10
Delaware : $0.11
Iowa : $0.11
Oklahoma : $0.12
Missouri : $0.12
Wyoming : $0.13
South Dakota : $0.13
California : $0.13
Florida : $0.14
West Virginia : $0.15
Arizona : $0.15
Kansas : $0.15
Maryland : $0.16
Texas : $0.17
Kentucky : $0.22
Mississippi : $0.23
South Carolina : $0.25
Arkansas : $0.25
New Mexico : $0.26
Virginia : $0.26
Michigan : $0.26
Pennsylvania : $0.27
North Carolina : $0.27
Ohio : $0.28
Minnesota : $0.28
New Jersey : $0.29
Maine : $0.33
Louisiana : $0.33
Vermont : $0.34
Alabama : $0.34
Tennessee : $0.34
Indiana : $0.36
New Hampshire : $0.40
Georgia : $0.43
Massachusetts : $0.44
Rhode Island : $0.50
Connecticut : $0.51
New York : $0.53
District of Columbia : $0.56
Hawaii : $0.77

It is about .15 cheaper here. Been that way mostly all Summer, seldom see that any more.