Diesel Exhaust Fluid

I have just bought a new Ram 2500 that uses DEF. I filled up the DEF tank when I got home, it was only half full from the dealer of course. I now have about 2000 miles on the engine. I have towed the fifth wheel around 200 miles and the rest have been truck only most on open highway speeds and some town driving. The gauge for the DEF is still reading full. I have burned probably 3 tanks of fuel since filling up the DEF. The gauge moves when turning the key off and on, so pretty sure it is working ok. The dealer service told me that the truck would burn about a tank of DEF to every 2 tanks of fuel, I am just concerned about it not using the DEF and causing some engine problems. Can someone enlighten me about this since it is my first experience with DEF, thanks.

I don't think your dealer knows what he's talking about. It's burned during regin mode. Your driving conditions as in towing, excessive idling etc will determine the usage. My gauge sticks on full for a long time before it starts to drop. Just don't let it get below a quarter of a tank by the gauge. I've got about 15K miles now and I don't think I've put more than 10 gals in at this point. I could be wrong there but It lasts a good while for me. Don't worry about the def. Just add when your gauge tells you to. Again, before long your gauge will start to drop. Just drive it and enjoy that new Ram, I love my 2500 Ram.

Thanks 'Lil Guy' was concerned is all, just new to this DEF thing.

OK, I was wrong. Regen is different. I just looked it up on google and it is supposed to be a gallon of def for 50 gal of fuel approx. They stated 1 in 50 and also about 2%. Regardless, just watch your gauge and sorry for the bad info on regen. Hey, I'm new on this too.lol I think the regen mode is when it dumps extra diesel in to burn out the soot in the filters. Some one else that knows will probably jump in.

DEF is used for emissions control and is used constantly. The harder you drive/tow the more the truck will use. Under normal driving conditions is seems to be minimal usage and will last for several thousand miles before needing to be refilled.

But make sure you never go empty on the DEF because it will cause these trucks to go into limp mode after a period of miles/time.

DPF filter is a whole different piece of equipment. The DPF filter collects the soot/biproduct from the fuel that is burned. Once your filter becomes clogged it then goes into regen which is when extra fuel is used to burn/clean out filter. The harder you work the truck such as pulling/towing then the exhaust temps are high enough that the soot will naturally burn off on its own. When you use these trucks for driving around town with no loads on the engine and the exhaust temps stay low then the soot will not burn off and is collected in the DPF filter.

This is just a basic break down.

I use approx. 5 gallons of DEF while towing heavy every 1000-1200 miles. When bob tailing or towing my light trailer, 6500 pounds, I will get between 2700-3000 miles to 5 gallons. I run it down until I get the refill message, 200 miles till de-rate, then add 5 gallons.

My truck uses about 1 gallon every thousand miles. More if I'm towing, maybe 1 gallon every 400-500 miles...Sounds like your service writer doesn't know much....Don

I have had both a Chevrolet HD 3500 with a duramax, and now I have a new RAM. The chevy sliverado definitely used less DEF than the RAM does.

Our 2014 Ram uses very little DEF when driving around town. When towing it guzzles DEF. Overall mileage is about 50/50 towing and I'm getting less than 3,000 miles for every 5 gallons of DEF.

I contacted Chrysler about the higher DEF usage on the RAM and was told that usage is normal.

Our former 2011 GMC got 5,000 miles for every 5 gallons of DEF.

When ever possible I add DEF at Flying J or other truck stops for about $13.50 for 5 gallons. Even on sale at stores, the best price I've ever seen is $20.00 for 5 gallons (two 2.5 gallon jugs on sale at NAPA) and $24.00 is more common.

My Ford uses about 1 gallon per 1000 miles. I buy mine at the pumps at truck stops. I have to pull around where the big rigs fuel up to find a pump with the DEF dispenser. It cost about $2.60 per gallon.

Ford info for comparison.

Ford's opine on DEF usage is that the system will burn approximately 1 tank of DEF (slightly over 5 gallons) to an "oil change interval" as determined by the onboard computers.

The Oil change interval is computed using data from all powertrain inputs, speed, pedal position, MAP sensor, exhaust temperatures, boost, coasting, accelerating, type of driving, empty tuck, pulling an 18,000 pound toy hauler etc etc etc.

All highway use with no load may show an oil change required at 10,000 or more miles. Or, towing a lot over mountainous roads may drop the oil change interval to 5000 or so miles.

With my truck, 65K miles now, of which just over 22K is pulling the Cyclone, I have found that my DEF usage approximates exactly what Ford suggests. 5 gallons of DEF per recommended oil change interval.

No different from GM and Ram or the OTR trucks, DEF will be based on the load and driving conditions.

danemayer said:

Our 2014 Ram uses very little DEF when driving around town. When towing it guzzles DEF. Overall mileage is about 50/50 towing and I'm getting less than 3,000 miles for every 5 gallons of DEF.

I contacted Chrysler about the higher DEF usage on the RAM and was told that usage is normal.

Our former 2011 GMC got 5,000 miles for every 5 gallons of DEF.

When ever possible I add DEF at Flying J or other truck stops for about $13.50 for 5 gallons. Even on sale at stores, the best price I've ever seen is $20.00 for 5 gallons (two 2.5 gallon jugs on sale at NAPA) and $24.00 is more common.

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Ditto, my Ram uses very little, I figured it out one time and it was so little it amounted to pennies per 100 miles. I cannot tell you how many times I have forgotten to fill it before hitching my trailer. Nothing like looking down at the notoriously inaccurate gage and seeing 1/4 of a tank while towing. The last fill up was at a Luv's where they have it at the pump.

I keep a 2.5 gallons container of DEF in storage just in case my 500 mile reminder fails. Just in case!

My experience is as Porthole says, I top up the DEF tank with 2.5 gallons of DEF twice a year. DEF is pretty much a big non-issue so far.

I carry a one gallon container of DEF in the truck. I figure a gallon would be enough to get to a destination where the DEF tank can be filled should one of low DEF warnings come on.