The antifreeze inside your Toyota Highlander keeps the water in your engine’s cooling system from freezing in cold temperatures. Water freezing inside the cooling system could severely damage the radiator and heater core, as well as the cooling hoses. Antifreeze also plays a vital role in inhibiting rust inside your Toyota Highlander’s cooling system. Over time, the ability of antifreeze to fight rust degrades. It is important that you change your antifreeze regularly.
Press down on the radiator cap and turn it counterclockwise, then pull it off the radiator.
Locate the petcock valve on the lower right corner of the radiator. Place a waste oil collection pan underneath it.
Open the petcock valve by turning it counterclockwise with a needle nose pliers.
Allow the radiator to drain completely, then close it using a needle nose pliers.
Fill an empty gallon-sized plastic container half full with fresh antifreeze.
Fill the rest of the container with water.
Pour the 50/50 mix of antifreeze and water into the radiator cap neck until the level of coolant in the radiator reaches 1 inch below the radiator cap neck.
Run the engine with the radiator cap off. This will bleed air from the cooling system.
Add enough of the 50/50 mix of antifreeze and water until the level of coolant in the radiator comes to within 1 inch of the radiator cap filler neck.
Place the radiator cap onto the neck. Press down and turn it clockwise.
