Cadillac Repair: 1999 Cadillac Deville Overheating, radiator cap, head gaskets

Question
I can leave my car running for hours without it overheating, but as soon as I start to drive it it starts heating up. I drove it without the coolant reservoir cap and it did not overheat but the antifreeze came out. Thermostat is working (new). Waterpump is working (new). Fans are working (new). Radiator is new. Is there a way to take out possible air pockets? Is there a cheap way to determine if it is a headgasket? I had a similar problem with an aurora and never found out what the issue was. Someone help please!

Answer
A simple way to check for faulty head gaskets is to remove all the spark plugs and put a constant approx 90 lbs of air into each cylinder one at a time and see which one or ones causes bubbles in the radiator cap opening or explodes the anti-freeze from the radiator cap area.