An oil leak in your head gasket can eventually lead to a blown gasket and expensive repairs for your vehicle. When you notice the leak, it is best to seal it up with an engine block sealer before any further damage occurs. These sealers contain sodium silicate, which turns into glass as it dries in the head gasket crack. This is not a long term fix, but can be effective until you can get the gasket leak repaired by a professional.
Empty the vehicle's antifreeze from the radiator. It can't mix with the sealer because the two chemicals can react with one another. Open the petcock on the base of the radiator to drain the antifreeze into a pan.
Safely dispose of the antifreeze according to the EPA rules. Check with a qualified mechanic if you are unsure how to do this.
Mix the sealant with water as instructed in the product's directions. Each sealant varies slightly but usually involves mixing with water. Pour the mixture down the vehicle's radiator opening. Wait for the vehicle to idle for 30 minutes while the mixture lodges in the cracks.
Remove the block sealer into a pan by releasing the petcock lever. Pour in new antifreeze.
Ask a mechanic to inspect your vehicle's head gasket when you are able and ready to put money into repairs.
If you do not plan on keeping your vehicle for any length of time, this is a satisfactory method, but is not a long term fix. This procedure only lasts a few months or a few years. Never add block sealer while the antifreeze is still in the vehicle since this can cause serious problems.