well an easy way I was told is to drill a couple (two) of little holes in the themostat (helps get the air out. here is what the Sean Hyland book has to say on the subject...
When filling from empty, purging the air from this (talking DOHC) system can be troublesome. The procedure we use is to fill the cooling system through the water crossover between the cylinder heads with the cap removed from the hearder tank. When the header tank fills, we tighten the cap and continue filling the crossover tube. Once the tube is full, the engine is started. The technician monitors the engine while it warms up, feeling the thermostat housing periodically, to feel when the thermostat has opened. Once the thermostat has opened, we continue monitoring, until the cooling fan has turned on, cooled the radiator, then shut off. Once this has occurred, the engine is allowed to cool, and then topped off through the header tank. If the thermostat fails to open, as it occasionally does, shut the engine off and let it cool, then restart the warm-up procedure. One thing we do which helps considerably is to drill a small hole in the edge of the thermostat. I notice the factory caught on to this idea in the 2003 cobra. The thermostat can be changed also exchanged for a cooler one. There is certainly some power to be gained in running the engine at 185 degress instead of 200. Try not to run to cold however; the engine requires some heat to make power............and it goes on and on.
Hope that helps!
