DEF usage

[AudiDudi]

My DEF indicator was down to 3 bars after 5650 miles (8700 miles total on the rig) and 11 months so I decided to add 2.5 gals. That brought the DEF indicator up to 8 bars and is a little over 2200 miles per gallon.

[jaherbst]

Good for you

Jack

[Hthunder]

My 2015 Cummings doesn't do that good. Pulling the fiver really sucks it down!

[Beachsailor]

Originally Posted by AudiDudi

My DEF indicator was down to 3 bars after 5650 miles (8700 miles total on the rig) and 11 months so I decided to add 2.5 gals. That brought the DEF indicator up to 8 bars and is a little over 2200 miles per gallon.

Per a MB tech. If you don't fill the DEF tank to the top the system does not reset and you may find yourself in countdown mode even with plenty of DEF in the tank.

[AudiDudi]

Originally Posted by Beachsailor

Per a MB tech. If you don't fill the DEF tank to the top the system does not reset and you may find yourself in countdown mode even with plenty of DEF in the tank.

Interesting. When I brought up the DEF gauge after adding, it sat at 3 bars for maybe 15 seconds (long enough for me to think maybe I needed to run the engine or drive it a bit), then it slowly added 1 bar at a time til it reached 8 bars.

[FFred]

Because of the problems involved we top off the DEF after every 60-70 gallons (3 fuel stops) .

Seems the stuff dries out and may take a long time to tell the computer all is well.

[Rkloud9]

Originally Posted by FFred

Because of the problems involved we top off the DEF after every 60-70 gallons (3 fuel stops) .

Seems the stuff dries out and may take a long time to tell the computer all is well.

I have found that 2500 miles is when a 2.5 gallon container will fill it to the top. We have a 2016 chassis, and I believe a dash indicator will let you know when it is down to about 40%. I have only seen it once, on our first trip, and I had to check the manual to figure out what it meant. As others have stated, keeping it above half is a good practice, as a white powder precipitates when it dries, and that stuff can mess up the tank sensors. Also, be scrupulously clean in the filling process, and if any is spilled, rinse it off with water, as it is acidic.

Happy travels!

[timfromma]

The DEF sensor in my Silverado won't register a low level until only 20% remains.

[flocktothewall]

We seem to fill our def up every 2000 miles or so. Our MB tech said it’s a 5 gallon tank but light comes on when 2.25 gallons are needed. We have a 2014 chassis no indicator on our model.

[AudiDudi]

Originally Posted by flocktothewall

We seem to fill our def up every 2000 miles or so. Our MB tech said it’s a 5 gallon tank but light comes on when 2.25 gallons are needed. We have a 2014 chassis no indicator on our model.

One my 2016, if you hold the maintenance button down within 2 seconds of turning on the ignition, it will show miles left to the next oil change and if you push it again (maybe twice more), it shows the DEF level similiar to the fuel gauge.

[tomkatb]

In 16,000 miles we have used 10 gallons of def fluid in our 2016 Ram 6.7 diesel.

I put a container in when the gage is under 50%

The truck does use more when towing, I think. We have towed about 700 miles of the 16,000.

I was surprised the truck towing a 14,000# fifth wheel got over 12 mpg. On somewhat hilly roads. Ky. Driving under 65 mph. 62/63 mostly.

Wish I had a larger fuel tank. However, I need a break every 200 miles.

[Mikegjax]

Originally Posted by flocktothewall

We seem to fill our def up every 2000 miles or so. Our MB tech said it’s a 5 gallon tank but light comes on when 2.25 gallons are needed. We have a 2014 chassis no indicator on our model.

My 2013 chassis DEF tank hold 3.2 U.S. gals. Others may be larger tanks. Light for mine comes on approx. 1 gal remaining.

[DaveJordan]

Originally Posted by Mikegjax

My 2013 chassis DEF tank hold 3.2 U.S. gals. Others may be larger tanks. Light for mine comes on approx. 1 gal remaining.

Right - light comes on early enough that a 2.5 gallon jug won't fit.

Found out the hard way...

Dave

[Greg-Gabe]

Our 2018 Dynamax has an almost 5 gal Tank and I’ve gone through about a third in 1800 miles. We have the steering wheel controls and it’s easy to check in menu. On ours it is broken down to quarter tank increments.