How to Check For an Engine Coolant Leak in a Vehicle

If your car's engine coolant leaks, it can mean big trouble with the engine overheating. Make sure your car's engine coolant system doesn't leak anywhere so you can be sure you have enough coolant available.

Difficulty: Moderately Easy

Instructions

1. Fill the coolant tank and measure the amount one day later. If it's empty or significantly lower, you probably have a leak -- especially if you refill it and see the same problem the next day.

2. Use a coolant pressure tester to check for any leaks. This is a small pump that attaches to the radiator neck and pumps air into the cooling system.

3. Examine all the hoses connected to the coolant tank. Look for any holes or punctures and replace any hoses that have them. Make sure the hoses are connected tightly.

4. Inspect the tank itself. The tank's surface is much harder than the hoses, but punctures can happen.

5. See if white smoke comes out of the exhaust pipe. This can mean a bad head gasket is causing coolant to leak into the combustion chamber. The gasket should be replaced.

6. Check the water pump. It is most likely to leak at the sealed bearing, as that wears down from rotation over time. In any case, the water pump should be replaced.

7. Search for leaks around the radiator, especially along the seams and vanes. You'll probably need to lie under the car and look upward with a light to inspect the radiator.

Tips & Warnings

• Do not be immediately concerned if you see a puddle after running the car, especially if the air conditioner was on or it is humid. This can simply be moisture from the air entering though the evaporator.
• Make sure you're putting enough antifreeze as well as water in the coolant. The antifreeze can prevent corrosion that will produce leaks.
• Sealing most leaks won't work well because the coolant will likely dissolve the sealant over time. The best solution is replacing any parts with leaks.