Originally Posted by wildbill23c
Thank you for the insight. Never understood what the issue was with the DEF, and still don't know much about it, other than here in Idaho, people tend to like the older diesel engines better like the 5.9L Cummins Diesel, and the Ford 7.3L Diesel. They frown upon new technology. So I've been hearing what everyone around here has said.
So how big of a tank is the DEF tank? And how long does it last? Does the level change depending on driving conditions like stop and go or is it all consistent?
Well, all of those people would be right. The 5.9 and the 7.3 are very reliable engines, but they are old in every way. Loud, low on power, specific fuel consumption is higher than new diesels, pollute more NOx (I don't consider soot a particulate), and very loud.
All those people saw was the introduction of EGR in 03, the DPF in 08, and the DEF / SCR in +11. Each move has had growing pains, but the new DEF / SCR engines are much more reliable than the 08-10 engines. Will they be as reliable as the 7.3....maybe not, but many of these people fail to remember how unreliable the 7.3 was until its final years. As well..the 5.9 had some serious growing pains along the way.
However, the repair costs of a new diesel are much higher.
DEF allows engineers to run higher cylinder temperatures. High cylinder temperatures cause NOx creation. In the 08-10 years, we used EGR as an inert gas to replace the extra O2 in the cylinder to keep the burn temperatures down. Now, we burn at the more efficient higher temperature and take care of the NOx we create using the aftertreatment of DEF.
The Superduty has a 7 gallon tank behind the fuel tank. Towing causes a bit higher DEF usage than driving empty, but you have plenty of warning in these new trucks. At least 500 miles worth of warning.