Originally Posted by jeffrapp
Lastly, I have read on other forums that one should not top up the tank, but wait for the warning light to come up before adding DEF. Anyone with any good information about this issue?
I am interested in this as well. I have only added DEF once, and I added when it was slightly under half. It took the whole 2.5 gallons and basically filled it up so I had no leftovers.
I would think if you waited, then you may have some leftover if you are buying it in the 2.5 gallon boxes. I guess I am not real sure how much the tank holds.