Tired of junk thermostats. Going with NOS. Do I need to drill a hole in in?

toolmanmike said
I have a Lisle brand spill free funnel that you fill the system with, let it run and the air will bubble it's way out of the system. Also, not cheap, but there are cooling system vac's that pull all the air out and then the suction draws coolant in. No air in the system. The small hole in the stat and let it run with the cap off is the cheapest and works well. Like mentioned before. Test every t stat before installing it. Many/most new ones don't work, right out of the box.

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Those work well. I had one years ago, but somebody liked it more than I did. It sprouted legs. I've not had much trouble though on conventional systems with trapped air. Now where the radiator cap is the low spot in the system, that's a different story.