Park your car: First of all, park your vehicle in a safe area. Find the Radiator: Secondly, find the radiator in your car. Most commonly, it is installed at the front of the car. Remove the Radiator Cap: After finding the radiator, remove the radiator car. Add the Water: Pour water into the radiator up to the desired level. Reinstall the Radiator Cap: As you add water according to the requirements, reinstall the radiator cap as before.