What's in the tree?

Brian and I pass this tree every time we head into Lebanon Tennessee. It's on the edge of a dirt drive way. I lightened up the picture a bit so you can see it way up IN the tree... hint, hint... way up IN the tree... what is it?

Many, many years ago a car hit this tree leaving behind it's radiator. Brian says it was an old car, very old car and a very long time ago.

I took pictures in the spring but you couldn't really see the radiator.... now with the leaves gone, you can.