We have a truck a guy brought in. He jumped right to the conclusion that his head gaskets were blown without us even looking at the truck. I have seen EGR coolers go bad on these motors but very few head gasket concerns. Has anyone else seen many head gasket issues on these motors? and he wants to do studs when he gets it fixed, so should he go with aftermarket gaskets or stock ones?? He also installed an aftermarket coolant filter.