DEF tank size

Measure it. length times width times height in inches divided by 231

Current Freighliner chassis have 13 gallon DEF tanks. Mike at Camp Freightliner says the average tank of DEF should last about 4500 - 5000 miles. I found that under severe driving conditions (mountains, heat, and high rpm) we achieved 4000 miles on the 13 gallon tank of DEF.

I can see it fine. But I'm not the best judge of the volume. Anyway, it was at half a tank and it took 5 gallons to read full on both gauges. I didn't try to fit in 3 more gallons. Just assumed it was full. And based on that I guess it's a 10 gallon tank.

It looks like the extra $50,000 dollars on the Fleetwood model gets you the larger 13 gallon tank, probably a tag axle too, plus a few extra niceties. :B

Thanks for all the replies.

Freightliner XCS is 13 gallons. I would think most are about the same. Can you not see it? I can see the entire tank in mine....and it looks to be about 13 gallons.

x2 mccsix. Mine holds 13 gal. 2013 Winnie Journey 40u.

Why not call the the guys that know at Freightliner 800-385-4357?

If you are worried.. Carry a spare gallon in basement storage.

It more closelly resembles part of the contents of the black tank (urine) than the contents of the fuel tank (Diesel fuel) so it's not a fire hazard.

It's a freightliner chassis. I only brought this up to see if my gauges aren't functioning properly. If it were a five gallon tank I would have filled it. Looking at the tank, well I'm not such a good judge of size I guess.

TucsonJim wrote:

robatthelake wrote:
DEF is Not Fuel so it has no bearing on Mileage!

What it does is clean the Exhaust system and reduce pollution.

But there is still a mileage factor to it. You consume the DEF over time and miles. Like I stated, I go about 1100 miles on one gallon of DEF. AT that rate, I could go about 5500 miles on one five gallon tank of the stuff.

DEF is not injected at a standard rate of fuel burned as many things cause increase and decrease consumption the biggest factors being humidity and air temp.

On my 2013 Tiffin Pheaton with a Freightliner XCS chassis the DEF tank is 13 Gallons.