Coolant is vital to your engine. A mixture of coolant and water circulates through the engine to absorb heat. The water pump circulates it in a loop past the thermostat, through coolant hoses, to the radiator to be cooled by air movement and then takes it back through the engine. If your engine runs low or is completely out of coolant, the overheating that results can cause irreparable damage to your engine.

Always check the coolant each time you check your the oil level in your car. If you’ve started to notice the level dropping between check- ups, it’s time to find out where the leak is occurring. If there is a coolant leak, you may see a puddle under the car or start noticing a sweet smell coming from the engine compartment after a drive.

Part 1 of 1: Find the source of the coolant leak

Materials Needed

Step 1: Do a visual check of the radiator, hoses and around the engine. Your vehicle has an upper and lower radiator hose, heater hoses at the back of the engine connecting to the heater core, and probably a couple of other smaller hoses going to the intake manifold or throttle body area. If a visual inspection reveals nothing, move on to the tried and true method of using a pressure tester.

Step 2: Use a pressure tester. Attach the pressure tester in place of the radiator cap.

  • Tip: If you don’t have a pressure tester or want to purchase one, some chain auto part stores offer tool rentals.

  • Note: The radiator cap will have a pressure rating on it. When you apply pressure with the pressure tester, be sure not to exceed that pressure on the dial. Always apply pressure to the cooling system with the engine off.

Step 3: Check again for a leak. Once pressurized, do a visual check around the engine bay once again. Be sure to check all the hoses, radiator itself, and all the coolant hoses and temperature sensors on or around the intake manifold. You most likely will find the source of your leak now.

If you are not comfortable with performing this check on your own, you can get your coolant leak inspected by a certified professional from YourMechanic.

This article originally appeared on YourMechanic.com as How to Find the Source of a Coolant Leak Faster and More Accurately and was authored by Ronny Brown.


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