MotoMaster Antifreeze Coolant Tester accurately tests all ethylene glycol antifreeze coolants in radiators. It is important to maintain your antifreeze coolant at the proper concentration level to ensure proper corrosion protection and prevent freeze-ups and boil-overs. Start by removing the cap from your overflow container. Turn your engine on and let it idle for 5 minutes. Draw the fluid slowly into the Motomaster Antifreeze Coolant Tester until it reaches the fluid level line. Tap gently on the tester to remove any remaining air bubbles. The large arrow on the tester indicates the degree of protection. Don't forget that the top arrow should be vertical while reading the results. The front scale on the tester indicates the freezing point while the back scale indicates the boiling point. Easy to use MotoMaster Antifreeze Coolant Tester accurately tests all ethylene glycol antifreeze coolants in radiators. Available at.. Canadian Tire