DEF

I just put in 8.4 gal to top off my tank. I have driven 2500 miles since I put any in and at that point I was showing 3/4 full about 12 gal and I had 5 gal left in the tank. So maybe 6 gal of usage for 2500 miles (the numbers don't work exactly because this is all estimates), mostly open road miles, it does make a big difference. Stop and go will eat your DEF tank much faster.

In a motorhome Cummins estimates a DEF usage rate of 2%. So, for every 100 gallons of fuel you would use 2 gallons of DEF. Assuming 8 mpg fuel mileage, that's 800 miles per tankful or 400 miles per gallon of DEF. At 2.79 per gallon for DEF that's .007 cents per mile.

I've used the truck stop DEF pumps once or twice, but even though my DEF fill is on the driver's side, it's so far back that I have to pull up partway after filling the diesel tank. So I mostly use the Blue DEF "boxes" from Wal-Mart, and generally add one (2-1/2 gallons) for each fill-up (usually around 90-100 gallons in my 150-gallon tank). That ratio seems to work out about right. I track my fuel use carefully, but haven't bothered to monitor my DEF usage any closer than this.

I have a 10 gallon DEF tank. I fill it about every 5th tank of diesel. So 10 gallons about every 400 - 500 gallons of fuel.

We have a 16 gallon DEF tank along with a 230 gallon diesel tank. I tend to fill the DEF at every 4th fuel stop. The chassis manufacturer moved the DEF filler to the driver's side a couple of years ago. The fuel and DEF fillers are behind the same door about halfway down the side of the coach.

We have just over 12,000 miles on the coach now and I recall going about 2,500 miles on the DEF tank. I'll check my receipts when I get back to the coach (in storage).

MM.

oldkeywest91 wrote:
On an average how much DEF are people using per trip(or tank fill up) on late model DP.

Never kept track...but I carry a 2.1 gallon can and every other diesel fill up I will fill the can and next campground will dump the DEF in...Chuck

I agree with luvlabs. We just dump in a couple of 2.5 gallon containers every so often unless I find an empty truck stop with DEF at the pump so I can go through backwards (my DEF tank is on passenger Side)

Depends on how long the trip is. Most diesels will use one gallon every 400-700 miles. Lots of miles when you have a 13 gallon tank.