Introduction: How to Find a Coolant Leak

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Video tutorial on how to find coolant leaks on your vehicle. Coolant leaks can certainly be risky on your vehicle as this can reduce the system’s pressure, drop the coolants level, and increase the chance of reducing air into the system. If left for longer periods of time, the leak may worsen and if caught off guard, can overheat the engine. Cooling systems are designs to keep a specified pressure, so when that decreases, that also increased the coolants boiling point. For every 1 psi increase, this will increase the system’s boiling point by about 2 to 3 degrees fahrenheit.

Tools/Supplies Needed:

  • cooling system pressure tester
  • ultraviolet light
  • dye
  • ratchet and socket set
  • replacement parts
  • coolant
  • distilled water

Step 1:

For this I am using a cooling system pressure testing kit. This kit comes with a pump, adapter, and various sized rubber fittings. As you can see there is three different sized rubber fittings which fits into the vehicle’s either radiator or reservoir. For this I already know what size is required and this will be based on which adapter fits into the radiator or reservoir hole when the cap is removed.

Step 2:

This test must only be done when the engine is cold so you do not risk burning yourself. Safety glasses are also recommended too. Depending on the vehicle you will need to test it at the tank if it has a pressurized system. If there is not a pressurized system, then test it at the radiator or within close proximately. Top up the coolant up is need be as we done not want to introduce air into the system and liquid also has a lower compression rate than compared to air. So if there is more air, the system will take much longer to pump up to pressure. Use coolant which is specific to your vehicle and only use distilled water. The pressure of the system should be located on the cap.

Step 3:

These simply screw onto the adapter, the threaded portion will need to be furthest away from the adapter mounting surface, then tighten and it will expand. You’ll need to tighten it up first so it fits snug, then insert it into the hole and continue to tighten. For this I am removing the engine cover so I can easily see any coolant hoses as the rear of the engine.

Pump up the system until it reads the specified value on the gauge. If there is a leak, you may not be able to achieve that maximum value or if you do, the gauge will slowly drop. For this I can see the gauge slowly dropping and I can hear a leak as in water dripping. Just taking a quick peak around the engine bay, I can see the leak is at the connection of the water valves which is used for the climate control. Beyond looking visually, you can also use the assistance of a system dye with an ultraviolet light such as this one. Also made by OEM tools, link for this product will be included in the description below. A dye can be purchased at your local auto parts supplier, dump it into the coolant system, allow the engine to run for a short period of time and then scan the area for leaks. The area will be illuminated by a fluorescent stain.In this case it was just a quick adjustment of the clamp to ensure it’s seats and tightened correctly.

Step 4:

Beyond looking visually, you can also use the assistance of a system dye with an ultraviolet light such as this one. Also made by OEM tools, link for this product will be included in the description below. A dye can be purchased at your local auto parts supplier, dump it into the coolant system, allow the engine to run for a short period of time and then scan the area for leaks. The area will be illuminated by a fluorescent stain.

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