aluminum. iron. coolant. corrosion. correct spec on coolant is in the owners manual in the back. the key is the additive package. the teksid 4v engine uses a different additive package than some of the other Ford engines, like the 4.0sohc which is also an aluminum engine but a different alloy. prestone has the spec on the back of the jug. don't just dump anything in there. distilled, not tap water. premix coolant is also a good thing. I'm just old school.
if you want to see how bad your coolant is, drop a millivolt volt meter probe into the coolant of the radiator and put the other lead on the aluminum block. if you see a volt, you have a battery for a cooling system and the additive package of the coolant is shot.
I was looking into Evan's waterless coolant for my Cummins powered truck, but I can't find a way to get all the water out of the block unless I pull the engine and turn it upside down. That monster has it's own cooling issues. I was looking at the Evans coolant for the Mark 8 but the heat transfer for the coolant is much better with the prestone or motorcraft stuff. there is no corrosion issue with the evans coolant because there's no water in it.
