Originally Posted by KJRitchie
What is the shelf life of DEF. When I purchased my Ram in August it was about 1/2 full and the dealer topped it up. I've got 1250miles on the truck and it still shows full. Guess I've not had a regen yet. After this last weekend trip next week there will be no towing until April. The truck will sit unused except for 1 day a week I plan to drive it to work. If the DEF gauge still shows full in February it won't be until next August when I will have the oil changed again. Will the DEF in my tank be too old?
KJ: DEF has no "shelf life". It's simply the chemical urea in a liquid form, which is a carrier for ammonia, so it won't "spoil" or go bad. DEF is a 67% water, 33% urea solution. Urea is the nitrogen portion of 15
-5-15 lawn fertilizer, for instance. The fluid is injected into the exhaust gas where it vaporizes, breaks down into ammonia, which then scrubs the exhaust of NOx compounds. It's an air purification method that's been around for decades for diesel engines, as well as gas turbines. It was originally a patented process in the industrial arena.
Running without it is really VERY hard to do.....it won't hurt anything, but the EPA is adamant that the manufacturers not allow us to do that, so we get an 800 mile warning plus more irritation the closer you get to empty of DEF.....
I have a Ford F250 diesel, and get about 30-35,000 miles on 6-7 gallons of fluid.