How to Find the Source of a Coolant Leak Faster and More Accurately

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.


Next Step

Schedule Coolant is leaking Inspection

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Recent Coolant is leaking Inspection reviews

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Matthew

9 years of experience
38 reviews
Matthew
9 years of experience
Mitsubishi Montero Sport V6-3.0L - Coolant is leaking - Denver, Colorado
As always. Matt is thorough and honest!! I hate it when I need him, but Matt is the ONLY mechanic I want messing with my car.
Mitsubishi Montero Sport - Coolant is leaking - Denver, Colorado
Matt is so awesome!! He came, pressure tested the cooling system, and found the leak, then fixed it. I was in a bind, and he really saved me. I would HIGHLY recommend MATT!!!!!!

Collins

12 years of experience
488 reviews
Collins
12 years of experience
Chevrolet Equinox V6-3.0L - Coolant is leaking Inspection - Atlanta, Georgia
He was great. He informed me about the issues I had with my car even giving me suggests about what to do with it.
BMW 650i - Coolant is leaking - Woodstock, Georgia
Collins showed up as expected and accessed the issue I had with my car. I initially assumed it was my radiator, but after an inspection of my car is was found to be a hose that needed to be replaced. He was very thorough with his diagnosis and pinpointing the exact issue. I am fully pleased with his service and professionalism.

Raymond

27 years of experience
223 reviews
Raymond
27 years of experience
Mini Cooper L4-1.6L - Coolant is leaking - Victorville, California
Raymond was great! I didn't feel like his recommendations for other services are forced which I really appreciate. Will definitely use his services again!

Jose

12 years of experience
49 reviews
Jose
12 years of experience
Chevrolet Classic L4-2.2L - Coolant is leaking - Riverside, California
Jose provided extraordinary customer service. He explained the issues with my vehicle and was professional and polite.

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