How to Plug a Leak With Sodium Silicate

You can use it at home to plug a leak in your car's radiator and save on expensive mechanic fees.

Using Sodium Silicate to Plug Leaks

1. Purchase sodium silicate at any automotive store.

2. Drain and flush out the cooling system (radiator, water pump, cooling fan and thermostat). Draining the radiator, which is typically located in front of the engine, drains the system. No antifreeze should remain when you are ready to pour in the sodium silicate.

3. Fill the radiator and overflow tank with water. The overflow tank is usually on the passenger's side of the car under the hood. Drain the water out to ensure the cooling system is clear of antifreeze. Let the cooling system stay open for 12 hours to allow it to dry and stay contaminant free.

4. Mix the product (one bottle=20 oz.) with 3 qts. of warm water and add the mixture to your car's cooling system. This is all the product you need for this process.

5. Start the engine. Turn the heater on high and the AC on high. Run the car for five minutes. Turn off the engine and allow it to cool.

6. Top off the radiator with water and start it again. Run the engine until it reaches the normal temperature. Continue running for another 15 minutes. Turn off the vehicle and allow it to cool.

7. Top off again with water and start the engine. Run it to the normal temperature and continue running it for another 15 minutes. Turn off the engine to cool.

8. Remove the radiator cap and drain the system. Leave it open for 12 to 24 hours. This allows the repair to set.

9. Flush the entire system with water and refill the radiator with antifreeze.