i have seen the effects of green coolant in 4age's you need a coolant with corrosion reseistance use nulon red and you wont have dramas with rusted thermostats for example.
welcome to coolant basics for imbeciles 101
firstly, thermostats are made from stainless steel so dont rust, the rust colour you may see is actually scale from iron molecules in the water ( if you havent bothered to use demineralised water like you should have )
secondly, the colour of the dye bears no relation to what chemicals are used in the coolant, its not the dye that reacts its the chemical reaction based on the ingeredients and the alloy composite ( just so we are clear dye does NOT form a chemical reaction with an alloy )
try not to spend your whole life with your head buried in the sand