A few weeks after my new radiator install. I've notice some grayish looking sludge on my radiator cap and in my radiator. It doesn't seem to effect my coolant temperature it stays at 160 degrees and the car runs and idles smooth, so could this be a sign of a leaking head gasket?
In the past when I worked at Pep Boys, they sold/sell some inferiour radiators. I remember seeing sludge as you describe and had looked inside a couple of the radiators that had been installed by the Boys. Looked like they were sealed in some areas with some sort of epoxy that was breaking down . A repp of the flushing machine had come to our shop and indicated to me that the coolant was high in some form of chemical. I don't remember what he called it but he advised to use a neautralizer. I called and he and I went our way. Maybe there is such a concept but I was not intrested in a excuse for selling such parts where I worked.