If your car has been diagnosed with a blown head gasket, your last resort is to try a head gasket sealer before you dump thousands of dollars on head gasket replacement.

Here you will find instructions on how to use a head gasket sealer. There are many head gasket sealers, but we will focus on using two of the best head gasket sealers.

Bar’s Head Gasket Fix

Bar’s Head Gasket Repair

Bar’s makes several head gasket repair sealers. The best head gasket sealer Bar’s leak makes the HG-1 Head Gasket Sealer. It is the strongest head gasket sealer, and it is antifreeze compatible as well. No need to drain the antifreeze to use this head gasket sealer. Here are the instructions.


  1. Make sure your engine is cold. directions on how to use head gasket sealer
  2. Remove the radiator cap only if the engine is cold. Remove the cap from the overflow reservoir if the engine is hot or doesn’t have a radiator cap. instructions on how to use head gasket repair stop leak
  3. Shake the head gasket sealer container.
  4. Add Bar’s head gasket sealer to the radiator. If there is no radiator cap, you can add it to the overflow tank. You should add the head gasket sealer to the radiator for fast results whenever possible.

Top off the radiator with coolant.

6. Start the engine.

7. Set heat to maximum using the climate control buttons on the dashboard.

8. Keep the engine RPMs at 1000 for at least 15 minutes.

9. Please turn off the engine and allow it to cool down for at least one hour.

How much Bar’s head gasket leak to use? 

  • Cooling system under 10 quarts / 2.5 gallons: Use 1/2 bottle (.5L).
  • Cooling systems over 10 quarts up to 20 quarts (5 gallons): Use 1 bottle / 1 L.

BlueDevil Head Gasket Sealer

head gasket sealer instructions

Below are instructions on how to use BlueDevil’s head gasket sealer (Part Number: 38386).

  1. Ensure the engine is cold.
  2. Drain the engine coolant.
  3. Remove the thermostat. Instructions on how to remove the thermostat vary between makes.
  4. Flush the cooling system using BlueDevil Radiator Flush.
  5. Next, fill the cooling system with water. Don’t top off the radiator, as you will need to add the BlueDevil head gasket sealer later.
  6. Ensure the engine is cold and remove the radiator cap.
  7. Start the engine.
  8. Set heat to max. Temperature and blowing fans to max. Using the controls on the dashboard.
  9. While the engine is running on idle, start adding BlueDevil via the radiator filler hole.
  10. Reinstall the radiator cap. Let the engine run for 50 minutes. During this time, it is important to monitor the engine temperature. Don’t let your car overheat. If the temperature gauge goes into the red, you should turn off the engine, let it cool for a bit, and restart it.
  11. After the engine has run for at least 50 minutes, let the engine cool down, then reinstall the thermostat.
  12. Drain half of the water from the cooling system. Fill the rest of the cooling system with the recommended Antifreeze.

We hope you find the How to use a Head Gasket Repair Sealer guide helpful. Check these troubleshooting and repair guides for more help on your vehicle.

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