What is it with DEF?
Just what is the Diesel Exhaust Fluid (DEF) ? What does it do and why do I need it? This is my first diesel and I never heard of it.
Forum Discussion
I would not buy some to keep on hand. It's too avaiable and it has a made on date (code) but they want you to keep it fresh. My 2011 dura max has been back 3 times for trouble. Last time I bought some from a pump and shortly thereafter message said poor quality See instruction book. You can not drain the tank, it must be pumped out. GM dealer did all the things the co. required and they reset the computer and in a couple weeks it happened again. This time with fresh GM DEF. so far no more trouble. BUT how does it work when the stuff is FROZEN SOLID?
