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How to Fix a Head Gasket With Engine Block Sealer

by Contributor

By utilizing science, you can fix a head gasket with engine block sealer. Sodium silicate is the main constituent of block sealer. It is a liquid that turns to glass as it dries, so the liquid fills the crack in your gasket, dries in the engine heat, and seals as it hardens. his is a cheap and temporary fix, but an effective one.

Step 1

Drain the anti-freeze from your radiator. The block sealer won't work properly with the anti-freeze in the radiator. To do this, locate the petcock on the bottom of the radiator, open it and allow all the fluid to drain into a pan.

Step 2

Dispose of the anti-freeze in accordance with EPA guidelines. A mechanic can assist you if necessary. Anti-freeze and block sealer is a volatile mix and cannot be in the radiator at the same time.

Step 3

Prepare the sealant mixture as indicated on the product's directions. Typically, you will add a specific amount of water to the mix, and then pour it into your vehicle's radiator. Idle your vehicle for about 30 minutes to let it settle in the cracks.

Step 4

Do a little aggressive driving to make sure the mixture moves around and fills in all the cracks. Drive the vehicle a day for the treatment to fully dry.

Step 5

Drain the block sealer and add new anti-freeze.

Get a new radiator or head gasket in your vehicle once you can afford the time and money for the repairs.


  • This is a good fix if your car isn't worth putting costly repairs into, or if you do not plan on keeping it much longer.
  • Dispose of anti-freeze in an appropriate waste container. Contact your local service station for information on responsible disposal.


  • Don't forget that anti-freeze and block sealer can never be in the engine at the same time. Drain one before filling up on the other.
  • This repair tends to last on the order of a couple months to a few years. Get it professionally repaired as soon as possible.

Items you will need

  • anti-freeze
  • radiator drainage pan
  • radiator disposal container
  • engine block sealer

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