I used to own a 2008 Cummins and although I never had trouble with it I heard many folks having issues with the emissions back then. I'm tossing around the thought of getting a 2015 Cummins and I'm just wondering what they're like now with the exhaust fluid? Are they pretty reliable? Does the fuel economy still around 12mpg empty? Thanks for any info I can get on this truck. I understand all Diesels these days have the exhaust fluid but if I got a truck it would be more likely a Cummins as they are better and cheaper than Fords and Chevys usually. Thanks....

Interesting read here about DEF.7. DEF will kill my fuel mileage.Quite the contrary. Because the manufacturer is able to tune the engine any way it wants to, and then allow the SCR and DEF to take care of the pollutants, most manufacturers have discovered better fuel mileage (compared to other smog-reduction systems). Truckmakers claim it improves fuel mileage by as much as 5 percent.as they are better and cheaper than Fords and Chevys usuallyThat should get some good comments. :S

Thanks! Very informative. So it appears these newer trucks might get a bit better mpgs? I talked to a guy who has a construction company and they have a 2015 dually and he said it got 15mpg from the get go so I'm assuming they're maybe going to be a bit better? Thanks...

That can be misleading at best. Because of the increases in HP and Torque fuel economy starts out worse. Heck, my 07 6.7L dually with 4.10 rear end returns a steady 17 at 70 MPH without DEF. Towing is 10.5 to 11.5. All hand calculated. That is every bit as good and in a lot of cases better than the new DEF equipped trucks are capable of with "better" rear end ratios.

The newer Cummins will not get the mileage my 03 does no matter how much def you use, but they sure are nicer inside and out.

GaryP, If the 2003 Cummins setup was available today we'd all be ecstatic lol. One thing I do remember about my 6.7L 2008 is that thing had extremely massive amounts of power to tow. That heavy truck would move and set you back in your seat. I've never driven anything else other than an old 24 valve here at work and it ran well but had nowhere near the power of that 6.7 it was a monster. I test drove a duramax once and that was my experience with GM Diesel other than a few half tons that seemed to always be lemons for me. At work we have a 6.4L powerstroke and that thing has some issues it barely has the power to move itself around....

Newer Cummins with Exhaust Fluid | Good Sam Community

donn0128
Explorer II
Mar 11, 2015
That can be misleading at best. Because of the increases in HP and Torque fuel economy starts out worse. Heck, my 07 6.7L dually with 4.10 rear end returns a steady 17 at 70 MPH without DEF. Towing is 10.5 to 11.5. All hand calculated. That is every bit as good and in a lot of cases better than the new DEF equipped trucks are capable of with "better" rear end ratios.
krazymatt
Explorer
Mar 11, 2015
Thanks! Very informative. So it appears these newer trucks might get a bit better mpgs? I talked to a guy who has a construction company and they have a 2015 dually and he said it got 15mpg from the get go so I'm assuming they're maybe going to be a bit better? Thanks...
BB_TX
Nomad
Mar 11, 2015
Interesting read here about DEF.

7. DEF will kill my fuel mileage.
Quite the contrary. Because the manufacturer is able to tune the engine any way it wants to, and then allow the SCR and DEF to take care of the pollutants, most manufacturers have discovered better fuel mileage (compared to other smog-reduction systems). Truckmakers claim it improves fuel mileage by as much as 5 percent.

as they are better and cheaper than Fords and Chevys usually
That should get some good comments. :S

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