radiator flush

So, i have some Engine Ice coolant left over from my motorcycle days. Has anyone had any experience with this product running in their intercooler? It is supposed to cool the engine by up to about 10-15 degrees or so.

My coolant is a little low and i need to top it off. Can i use the the 50/50 automotive stuff? I cant find specific marine antifreeze anywhere. Also what is the procedure for a drain and flush for the closed loop system? Thanks!