removing stuck bolts, nuts, plugs, etc
 

I own lots of cars, and have found that the best way to remove a rusted or stuck fastener is to first give it a bit of tightening. Just the slighted bit. That usually breaks the rust interferance and then you can remove it quite easily. If you need to use heat on a bolt, heat it, with oxy acetylene till it's cherry red and let it cool by itself. Do not quench the bolt with water. This actually shrinks the bolt. The idea of the heat expanding a nut is just an idea and dead wrong. You can heat stuff and then as they cool apply "liquid wrench", or other items that will wick into the joint and maybe aid in removal. Just my 2 cents.
Mike