I added a small amount of green antifreeze to my organization's Chevy 1500. I later noticed a sticker that stated to add only Dexcool antifreeze and that anything else could shorten the the required time between coolant changes. So, I have a few questions: 1) Will non Dexcool coolant really shorten the required time as stated or is this a product markup? 2) If it is bad to have added a different kind of antifreeze, is it as simple as just shortening the life of the coolant in the system or can the results be more dire (i.e. corrosion to the engine or radiator)? and 3) If you recommend flushing the system and putting straight Dexcool back in, can I use the flushed Dexcool/green mixture safely in other vehicles that take regular antifreeze? To clarify, I added perhaps a half gallon or less of the green into our Chevy's system. Thanks for your help,