Test the antifreeze in an automobile using an antifreeze tester. This device includes a squeeze bulb to pull antifreeze from the radiator, a cylinder with floating balls, and a tub to reach into the radiator. The number of balls floating in the liquid indicates the concentration of antifreeze in the coolant solution.
Never open the radiator on a vehicle while it is hot. The steam and pressure can cause severe burns. Once it is cool, open the radiator cap slowly, stopping when it stops turning and allowing the release of any pressure that remains inside the tank. Then press down on the cap, and turn it to the second stop. Lift the cap to access the coolant for testing.
Once the cylinder is full of liquid, hold it to the light to determine the number of floating balls. The tester packaging provides information to convert this number to a concentration. Most manufacturers recommend maintaining a 50 percent water and 50 percent antifreeze mix. Generally, the larger the number of balls that float to the top, the better protection the car has against freezing
Antifreeze comes in several colors. Check the fluid for floating particle of rust. Some owners mistake red-colored antifreeze for rust, but the red colors alone do not indicate a problem. Floating particles indicate it is time to have a shop flush the system and replace the coolant.