I don't know if you do any off-roading or not, but I was getting serious overheating because my radiator was packed with mud. I had to pull off my radiator fan shroud (I have an electric fan mounted in the shroud) and pretty much hold the nozzle of the garden hose right next to the engine side of the radiator to get it cleaned out.

After that, I installed a couple of relays behind my front fender and a switch in the dash to let me shut off the fan and also reverse it if need be (thought it might help push fresh mud out of the radiator after a nasty crossing).