The Stovebolt Site Forums The Shop Area Engine Shop Removing my well-rusted intake/exhaust manifold

The best method I've seen work is to heat up the manifold around the bolt you want to remove with a torch. Get it glowing and then very gently work the bolt out. The idea is to expand the cast metal of the manifold which allows the bolt to spin. While I definitely recomend the torch method, the best penetrating oil I've ever used is an AC/Delco product available at a GM dealership. Used to be called Super Penetrant and is now called something like Rust Inhibitor and Heat Valve Lubricant. Good luck.