Going from bad to worse, and eventually covering the ugly, we’ll kick things off with the inconvenient failure nearly every 6.4L faces at some point in its life time: a leaking radiator. The issue occurs when the crimps that hold the aluminum core to the plastic end tanks stretch, allowing the two to separate. Some attribute the crimp failures to the upper radiator support allowing too much flex to occur at the top of the radiator. Regardless, throughout the 6.4L’s production run, Ford was never able to rectify the radiator problem.