The Best Tool to Find Coolant Leaks

Arguably one of the most time consuming mechanical issues for a mechanic to properly diagnose is an overheating situation. Due to the fact that there are so many individual components, part failures, and symptoms that lead to overheating, many mechanics find it difficult and extremely frustrating to:

  • Find the source of the overheating problem
  • Determine if there are leaks in the coolant system
  • Locate the precise part or component that is faulty

However, there is a great tool and process that some of the most experienced ASE certified mechanics utilize to quickly diagnose overheating issues and detect coolant leaks which, when used properly, can save time and decrease your downtime on repairs. This tool is a coolant pressure tester.

The Best Tool to Find Coolant Leaks - coolant pressure tester
Image: Mac Tools

What is a coolant pressure tester?

A coolant pressure tester is a tool that most ASE service stations and independent certified mechanics use to diagnose a coolant leak. The tool itself is similar in many ways to a bicycle pump, with a pneumatic hose attached to a special adapter that is hand pumped after you attach the correct adapter fitting to the vehicle’s radiator. Once you secure the attachment to the radiator, you simply pump the pressure handle until the gauge reads about 15 psi and watch and listen for leaks to appear within the coolant system.

The tool itself is simple to use. However, the best mechanics know how to use the tool correctly to diagnose leaks in the entire coolant system. Since coolant leaks contributes to more than 80% of most overheating situations, using the coolant pressure tester correctly can expedite the search for most overheating problems.

How to use the coolant pressure tester effectively

When a customer contacts a mechanic about their car overheating, what’s the first thing that pops into their mind? Most ASE certified mechanics, instantly remember that faulty thermostats, broken water pumps or low coolant levels or coolant leaks are the main causes of the overheating situation. They also tend to remember from their training that one of the first things they should do when diagnosing a problem is to eliminate some of the potential causes through simple tests. When it comes to finding coolant leaks, this is best completed by using the coolant pressure tester correctly.

Here is how to do it right:

  1. Let the engine cool down for about an hour
  2. Remove the radiator cap
  3. Attach the correct adapter to the radiator
  4. Attach the coolant pressure tester
  5. Pump the coolant pressure tester slowly until you approach 15 psi on the gauge
  6. Once the gauge has reached that 15 psi level, make sure to do the following:
    • LISTEN for any air leaking from any fittings, hoses or the radiator itself.
    • WATCH for any leaking fluid coming from welds in the radiator, hose fittings or bends in coolant lines.
    • OBSERVE the pressure gauge. If you don’t hear anything or see fluid leaking onto the ground; leave the gauge attached for about 20 minutes. If the pressure does not fall more than 1 to 2 points, there is no coolant leak and you can move onto another potential cause of the overheating situation.

Having the flexibility to easily find a coolant leak is much easier when you use a coolant pressure tester; and use it correctly.

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Recent Coolant is leaking Inspection reviews

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Rating Summary
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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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