Identifying Restricted Radiator Cores
Bring the engine up to operating temperature. With the engine still running, slowly pass your hand around and in close proximity to the FRONT of the radiator core. Unless the surface is excessively hot, actually touching the surface is preferable. Temperature of this surface should be relatively uniform, over the entire radiator core. Any areas that appear noticeably cooler suggest regions where coolant is not circulating, thereby reducing radiator surface temperature. This condition often manifests itself as operating engine temperatures slightly higher, but not necessarily to excess, than normal radiator core temperature. Note: Do Not try to place your hand on the engine side of the radiator and into the cooling fan blades !
