Some folks have drilled a small hole in the thermostat if there's not one already there. They say that it allows any air to burp out of the head and allows for more efficient t-stat operation. I think they usually drill a 1/8" hole. Hope this helps.

David Colter
pics * 1954 wrecker * [color:#009900]1948 Chevy 1-Ton[/color]
No act of kindness - no matter how small - is ever wasted ~~ Aesop