I have a vanagon that I just bought recently. Everything seems to be
running well, but the coolant level in the overflow tank is a little
low, and I'd like to top it off. The previous owner said he was using
phosphate-free coolant, but I didn't think to ask which brand it was.
Is it okay to mix coolants in between system flushes? I expect I'll
read the list archives and try to find a recommended phosphate-free
coolant at my FLAPS. I don't think it will be all that easy to find
the VW blue stuff around here, nor does it seem manditory.