Hobbies Cars & Motorcycles How To Check Your Coolant Mixture Percentage Share PINTEREST Email Print ollo / Getty Images Cars & Motorcycles Cars How Tos Buying & Selling Basics Reviews Tools & Products Classic Cars Exotic Cars Corvettes Mustangs Tires & Wheels Motorcycles Used Cars SUVs Trucks ATVs & Off Road Public Transportation By Matthew Wright Matthew Wright has been a freelance writer and editor for over 10 years and an automotive repair professional for three decades specializing in European vintage vehicles. our editorial process Matthew Wright Updated September 10, 2018 Keeping a proper coolant mixture and the correct level are vital to your car's health. Antifreeze should be close to a 50 percent mixture, depending on your climate and driving conditions. But how are you supposed to know whether your vital to your car's health. Antifreeze should be close to a 50 percent mixture, depending on your climate and driving conditions. But how are you supposed to know whether your coolant mixture is right for you and your car? You can test your coolant mixture easily with an inexpensive coolant mixture tester that can be bought at any auto parts store. Remember, never try to remove your radiator or coolant reservoir cap while the engine is hot. The coolant is very hot and under high pressure, which can burn you badly. 01 of 02 Taking the Coolant Sample To test your coolant mixture, you'll need to take a sample from your radiator or coolant reservoir, whichever's easiest. Be sure to let your engine cool down before you remove your radiator or coolant reservoir cap. Once the engine is cool, open the cap and suck a sample of coolant into the test tube. 02 of 02 Reading the Results Once you have an adequate sample of coolant in the test tube, hold it up to any light source so that you can see through the tube of coolant. The sky works best if you can be outside. Give it 30 seconds or so to stabilize, and then look to see how many balls have floated to the top of the tube. The more balls float to the top, the more protection against freezing your car has. There will be markings on the tube to use as a guide, and they are usually explained further on the package.