Adding (and tracking) DEF - 2014 Ram 1500 EcoDiesel Long-Term Road Test

2014 Ram 1500 EcoDiesel Long-Term Road Test

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2014 Ram 1500 EcoDiesel: Adding (and tracking) DEF

November 5, 2014

2014 Ram 1500 EcoDiesel

Along the second leg of my 1,300-mile road trip, our long-term 2014 Ram 1500 EcoDiesel gave me a warning on the center screen that it was time to add some diesel exhaust fluid. I noticed the gauge was low before the trip, so I pre-purchased three boxes of DEF ahead of time. At my next stop, I added 7.5 gallons of DEF and logged the mileage. Here's a breakdown of all the DEF we've added to the Ram so far.





 Per Gallon





















As you can see, the cost of DEF varies pretty widely depending on where you purchase it. On August 8 we paid for the convenience of having a dealership add the fluid during the Ram's first service, and per gallon, it cost more than double what I paid for it at Pep Boys. The Ram came to us with a full DEF tank and we've used 19 gallons of fluid so far.

If you average out the total price of DEF we've already purchased ($120.05/15,748 miles), it comes out to $0.0076 per mile. At the highest rate we've paid ($9.75 per gallon) that would mean an increase to $0.0118 per mile, and if you calculate using the least expensive fluid we've purchased ($4.40 per gallon) the price drops to $0.0053 per mile.

During the last six months, the Ram has consumed 669.1 gallons of diesel fuel and with the current national-average-cost of diesel fuel at about $3.64, that's a total cost of $2,435.52. With those numbers, diesel fuel works out to cost $0.1547 per mile.

Extrapolating these numbers and using the current national average for diesel fuel, the fuel cost over 20,000 miles is $3,094. Over the same distance, purchasing and pouring your own DEF would cost you about $106, while having a dealer do it would approximately $236.

The cost-per-mile of fuel is considering our current mileage of 22.7 mpg (0.7 higher than the EPA combined estimate) and the fact that we're only halfway through our year-long test with the Ram. This means these numbers will likely change a bit, but we'll continue to track DEF usage and what it adds to the cost of ownership.

Also, the windshield washer fluid was low, so I added a gallon of fluid to that reservoir. It cost two dollars.

Travis Langness, Associate Editor @ 15,478 miles

2014 Ram 1500

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