OLD DEF??
Recently, going from a 5th wheel to a used DP I have a question about the age and effectiveness of DEF that is in the tank of a little used motorhome over the past year. As a driver of a Diesel picku...
Forum Discussion
Suck it out and put in new when you get ready to drive it. It has a shelf life of 18 months, so you sort of need the jug it came in to know for sure.
