Ok first of all, i would just like to say..i never expected the amount of mess i would create draining the coolant from the block...good lord [80?] Anyhow, i have no idea what type of coolant the previous owner used. I think it looked green if i remember right. Anyhow i purchased some BMW coolant from the dealer because it is suppose to be the best for our engines. But from what i understand BMW coolant is blue isnt it? Can i switch to blue coolant? I know u cant interchange between the red and green because it creates a sludge. But will i be ok making this switch? It could have been cheap prestone in there for all i know. Thanx for the help guys.