And give it a good bleed when your refilling! I found it best to remove the temp sensor, top radiator bleed screw and the bleed screw on the heater and fill the system gently waiting for water to come out of first the top of the radiator then the temp sensor then after you've screwed them both back in, run the car with just the heater bleed open then as it warms up screw it back in.
Trapped air is probably the biggest cause of blown head gaskets on BIS models as there are so many corners and nooks that air can stay. With the fact that the radiator has very little airflow and the thermostat located at the bottom of the engine, a water pump that runs off a shaft that's powered by the camshaft and enough coolant hoses to wrap around the car It's probably the most awkward and complicated cooling system I've ever worked on and does work as designed but everything has to be in good shape that includes making sure the fan cuts in (both times as it has a slow setting and a fast setting for when it gets hotter)
