Turn off the engine and let it cool down.
Open the hood of your car.
Locate the coolant reservoir. It is a clear plastic tank with a black cap.
Unscrew the cap and remove it from the reservoir.
Look inside the reservoir and check the level of the coolant. If it is low, you will need to add more.
Mix 50/50 antifreeze and water in a separate container. The amount you will need depends on how low the coolant level is.
Pour the coolant mixture into the reservoir until it reaches the "FULL" mark.
Replace the cap on the reservoir and screw it on tight.
Close the hood of your car.
That's it! You have now successfully replaced the radiator water in your 2003 Passat wagon.
