Ok, not to insult Kenny in any way, but I hope you didn´t go with his idea about taking the thermostat out. That is a big No No. The thermostat keeps the coolant in the engine log enough for it to absorb all the heat it can, whil at the same time allowing the coolant in the radiator too cool down enough to actualy cool the engine once the thermostat opens. Removing it could cause it to over heat quicker by not allowing the coolant to stay in the radiator long enough to cool down. As far as "Air lock" goes, If you have an air pocket in the engine, then there is essentially a spot that isn´t getting cooled properly since water isn´t touching the part with the air pocket, it can´t absorb the heat. I have read in a number of places as well as done this myself, but if you drill a hole about 1/8 inch round in the flat part of the thermostat this will allow any air to escape while the thermostat is closed, but yet allow enough of a restriction to keep the water in the radiator so it will cool down. Hopefully this helps a little bit.