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

The most popular service booked by readers of this article is Coolant is leaking Inspection. Once the problem has been diagnosed, you will be provided with an upfront quote for the recommended fix and receive $20.00 off as a credit towards the repair. YourMechanic’s technicians bring the dealership to you by performing this job at your home or office 7-days a week between 7AM-9PM. We currently cover over 2,000 cities and have 100k+ 5-star reviews... LEARN MORE

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Rodney

37 years of experience
611 reviews
Rodney
37 years of experience
Mini Cooper L4-1.6L Turbo - Coolant is leaking - Sacramento, California
Rodney quickly found out what was wrong. He knows a lot about our car. He is friendly and professional. I feel like he has our best interests in mind, we trust him.
Pontiac Sunfire - Coolant is leaking - Sacramento, California
Outstanding!! Extremely knowledgeable, and knew exactly what to look for I would recommend Rodney and "Your Mechanic" services!

Shane

18 years of experience
379 reviews
Shane
18 years of experience
GMC Canyon V6-3.6L - Coolant is leaking Inspection - Round Rock, Texas
Shane arrived early and provided photos showing what the issue was (water pump). He also gave me helpful information on what to do until I could get it replaced.
Ford F-150 - Coolant is leaking - Georgetown, Texas
Described to Shane what I thought the problem might be. He looked at the truck and found it wasn’t as dire as I thought. Thanks Shane.

Kevin

25 years of experience
29 reviews
Kevin
25 years of experience
Hyundai Elantra L4-1.8L - Coolant is leaking - Arlington, Texas
Kevin was absolutely wonderful! He explained everything in detail, diagnosed my issue quickly. Very informative, honest and great communicator! 5 stars aren’t enough, he was top notch!

Michael

28 years of experience
672 reviews
Michael
28 years of experience
Lincoln Aviator V8-4.6L - Coolant is leaking - Tempe, Arizona
Michael is amazing - Very knowledgable and is a straight shooter. This is already my 2nd time using him and will continue to reach out to him if I have any issues with any of my vehicles.

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