I drill a small hole in all my t-stats. I also have another tool I use while warming up a fresh refill. It's a rather large funnel that attaches to where the radiator cap would normally, which elevates the highest point of coolant, which is often higher in the heater in new cars than the engine. I can watch it run and burp until I'm satisfied that all is good. Your local FLAPS should have one available from Lisle if you don't have the Snap-on truck coming to your door. I have both, one in my work box and one at home.
Devin
