How to Check Your Car's Coolant (Antifreeze) Safely

Coolant, also called antifreeze, keeps your engine from overheating in summer and freezing in winter. Checking it takes a minute, but there's one rule you can't skip.

1. The Rule: Engine Cold Only

Only check it when the engine is cold. Wait at least half an hour after driving. A hot cooling system is under pressure, and opening it can spray scalding coolant and steam.

2. Step 1: Find The Overflow Tank

Pop the hood, and look for a see through plastic tank, usually near the radiator, with a hose running to it. The cap often has a warning symbol on it.

3. Step 2: Read The Lines

You don't need to open anything to check it. Look at the side of the tank. The coolant should be between the low and full marks. Use the cold line, if it has one.

4. Step 3: Top It Up If Low

If it's below the low mark, slowly unscrew the tank's cap, and add coolant until it reaches the full cold line. Don't overfill it. Use the type listed in your owner's manual. A premixed fifty fifty jug is the easiest.

5. Leave The Radiator Cap Alone

For a routine check, add coolant to the overflow tank only. Don't open the radiator cap itself.

6. Keeps Going Down?

If you keep having to add coolant, you may have a leak. Look for puddles under the car, and have a mechanic check it. Wipe up any spills right away. Coolant is poisonous, and its sweet taste can attract pets.