Umm, yeah, I bought that and was told its not recomended. I was looking at it in Sprchp today and theres some called 'Tefylon' or something like that and a Castrol branded AntiFreeze/AntiBoil, I'd go for one of them.
Also the concentration level is a recommended minimum (33% means add 1 part AF/AB and 2 parts distilled water) so IMO I would create a mixture of 40-50%.
The flush I guess is fine.