How to Repair a Radiator With Epoxy

Written by brenda priddy
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How to Repair a Radiator With Epoxy
Avoid this stop with the advice here. (radiator humour image by John Sfondilias from

One simple way to repair a broken or leaky radiator is to create a patch made from epoxy.

The epoxy seals the leaking areas of the radiator and creates a strong enough patch that

the radiator should continue to work for several years. This is one of the

most inexpensive methods for cleaning and patching a radiator.

Skill level:

Things you need

  • Needle nosed pliers
  • Denatured alcohol
  • Brake cleaner
  • Masking tape
  • Epoxy

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  1. 1

    Remove as much of the damaged area of the radiator as possible with needle nose pliers.

    Remove any damaged pieces of the fin area and pinch any damaged waterlines closed.

  2. 2

    Pour a half cup of denatured alcohol over the damaged radiator. Turn the radiator on

    its side so the alcohol drips out of the radiator, taking any dirt and oil with it. Spray the

    surface of the radiator to eliminate any remaining oil.

  3. 3

    Cover the entire damaged part of the radiator with masking tape. Cover about two

    additional inches of radiator on all sides to seal off the damaged portion of the radiator.

  4. 4

    Pull any damaged fins away from the radiator tubes with needle nosed pliers. This does

    not have to be a precise job, as the patch will repair the damage. Lay the radiator damage

    side down on a flat surface.

  5. 5

    Mix the two parts of the epoxy. The consistency should be about that of syrup. If the

    epoxy is too thick, then thin the mixture with denatured alcohol until the epoxy has the correct consistency.

  6. 6

    Pour the epoxy mixture into the underside of the radiator, near the damaged area so that the epoxy will slide over the damaged area and seal any leaks in the radiator or water tubes. Allow the epoxy to dry for 24 hours.

  7. 7

    Remove the tape and test the radiator. Place the radiator back inside the vehicle and turn

    the unit on. The radiator should function normally without smoking or leaking water. If it

    still leaks, then apply a second coating of epoxy patch.

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