well im using a radtec ally rad, it never overheats but generally runs hotter than it used to, average halfway up the guage to 3/4's and fans constantly cutting in. its definately not an airlock because ive vacuum blead the system, its just not possible to be an airlock now. wondering if the waterpump blades have corroded down slightly and that theres too much of a gap between the fins andhousing thus not creating a vauum/ presure effect and not circulating well enough.