Finalize Coolant Level and Seal the System

What happens here

Once bubbling subsides and the engine temperature stabilizes at its optimal range (around 180°F), the creator tops off the coolant in the funnel. He then uses the specialized funnel's internal plug to prevent spillage as he carefully removes it from the radiator opening. Finally, he securely replaces the radiator cap. He reiterates the importance of turning on the heater during the bleeding process to ensure all parts of the cooling system, including the heater core, are free of air.

Goal: Ensure the cooling system is completely filled, air-free, and properly sealed