<b>Cooling: </b>Remove the radiator cap and look inside before warming up the engine. Rusty water isn’t all bad, but look for potential leaks. Oil in the radiator indicates a blown head gasket. Check hoses and belts, too. If you can, drain a small amount of the water/rust out so you can see if the top of the core is clogged. Even with all the rusty muddy water we found in our radiator, the core wasn’t clogged, so we were good to go with a little flushing and some fresh water.