>not to deviate from your topic too much, but i was curious, what is 
>observable on the engine which would indicate problems with the head 
>gasket/cooling system? TIA

Blue/green drops of antifreeze under the engine by the cylinder heads, or 
blue white encrustations in same area, or on the cylinder head nuts visible 
in the engine compartment.  If the hot air at the windshield is quite a bit 
cooler than that at your feet, then you have an airbubble in the heater 
core, and maybe in the radiator too, that's how I know when to bleed my van. 
tim s.