You can have your radiator rodded out at a radiator shop depending on the radiator. It's just like cleaning your gun barrel after shooting. It just pushes out all the accumulated crud and gunk that has been building up in there since day one. You could probably do it yourself too. I think you just have to remove the side caps which give you access to the radiator cores which are just horizontal tubes. Then find the right size rod to use(like possibly a .223 or .308 brass jag).