[EcoCivic]

As the title says, I'm wondering how important the thermostat's little bleed hole is. From my understanding, its purpose is just to allow a tiny bit of coolant circulation all the time to make the initial fill easier and prevent problems when the cooling system isn't refilled properly.

Since I always use my spill free funnel when adding coolant and let the engine run at varying RPMs until the thermostat opens and then until there is no air left, would it be safe to block off the bleed hole for a little faster warmup and more stable temps in cold weather? Possibly even slightly better block heater performance and a slower cool down since a thermosyphon through the radiator would be prevented?

I would normally just try something like this and see what happens, but the thermostat I'd be trying this on just cost me nearly $100 and that was a deal, so I'd rather not destroy it.

I'm thinking not having a bleed hole should be safe since the system will be completely bled before the car is driven and air should pass through an open thermostat no problem, but any input would be appreciated!