Do you put drill a small hole in your thermostat?

MoparMike1974 said
I have seen them come with the bleed hole but I have never had the need to add one that didnt. So long as your filler neck is the highest point, any air will naturally work its way out.

Only after the thermostat opens. It's more when you refill the system and start it up to warm the engine. (like a freshly rebuilt engine)