[mrnickleye]

Gasses get into the heater core due to a BHG.

Air gets into the heater core when the coolant level is allowed to drop in it. I suppose you could pinch the 2 heater hoses before you open the system, to prevent the coolant from coming out.

But I don't recommend this with old hoses, as it may cause them to leak later.

Also, the dangly thing on the thermostat can be snipped off before you put it into place. This will allow air to 'more easily' escape from the engine, and into the radiator, where it eventually will be pushed out into the coolant recovery bottle.

And....even opening up that hole by drilling it to 1/4" will NOT effect the operation of the thermostat, as it will still open and close normally, to allow the flow of coolant.

When your system is up to temp, the thermostat is wide open anyway.

Remember, the 7m motor (with a standard pump) does not flow much coolant at idle. AND...the fan does not draw much air at idle. I read many threads where the fellow says it gets hot at the stop light. Thats why I use an electric fan here in the desert.

I am mostly driving in town, with the A/C on, so I want lots of air thru the radiator at all those stops.