Thanks all. That is encouraging. Does anyone know what happens if you use "outdated" DEF?? Does it just not clean up the emissions correctly, or is it more severe?
After I posted the original post, I realized that when we bought our new motorhome in February, it was a left over 2013, and probably the DEF had been sitting in the tank for a year or more, including a summer here in Florida. I never detected any problems with that tank full, so probably it isn't really critical. Your answers have sort of confirmed that.
thanks again,
Ed Headington