My current fill is only 6 months old.
But it IS kinda thin with,70%dist water, 1 bottle RWW and 26.5% AF (the RWW is about 3.5% of a Q's cooling system).
KY winters are mild, I may run this thru the winter, but I will monitor temp predictions, if they go below -20F or so I will changeto thicker mix, but in teh 2 winters I been here so far its been that low only once.
And even if it were to get that cold and my current fill is only good to -20F, all i would have to do is run the car warm in the evening and teh coolant will stay plenty warm until the morning start.
But if I have to leave town for a couple weeks mid-winter it will get a rad drain and refill, with all AF, bringing it up to about 50/50.
Fred...
