A little trick for helping to bleed the cooling system. When you install the t-stat, drill a 1/8" hole in the flange of the t-stat. IF your stat mounts sideways, make sure you install it with the hole at 12 o'clock. If it mounts flat, it doesn't matter. This hole will give the air a way to escape when the t-stat is closed, making bleeding much easier. It will have no effect once the t-stat opens.