Even when no leak is visible, it is a good idea to check under the hood to ensure that all of the fluid containers are filled to their appropriate level. This may involve opening caps and removing dipsticks, but it is an important step towards ensuring that the vehicle is ready to drive. The Carfax website recommends checking oil, transmission fluid, antifreeze/coolant, radiator coolant, brake fluid, windshield washer fluid and power steering fluid to ensure that they are at the proper levels.