ok try to stick with me on this one i installed a greddy fmic on my 93 fd and in the process i took out my radiator out and drained the system so i finished the install everything looked great topped off the cooling system it didn't take to much coolant so not knowing what that little tank on the side was (ast) i topped that off to a few min later it poped a leak ?? was that due to the coolant in the ast or do those crack normally ??? please help

 

ASTs fail fairly often. Most of the vendors have an aluminum replacement available.