lmao...that was me until a couple months ago, I went with the Valvoline 5w40 syn & will stay with it year round from now on. NAPA has it on sale $19.99 a couple times a year around here so I just plan on buying it then. :)
depends on what coolant is in it now, it's probably the Ford Gold stuff.
I always keep a little mixed 50/50 to top off
if you put the wrong stuff in you might be in for a heluva mess so make sure what's in there before you go adding