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Cooling System Seal Tabs | ACDelco

ACDelco Cooling System Seal Tabs are designed with a non-toxic organic formula for use in radiator systems to seal and prevent leaks due to casting porosity in engine components. The tabs dissolve to lubricate internal components and seal coolant leaks. ACDelco Cooling System Seal Tabs also inhibit the formation of rust and scale, neutralize pH imbalances and control electrolysis.


  • Professional-strength formula creates a permanent seal against minor or microscopic leaks and porosity
  • The compatible seals work with water and all types of antifreeze including conventional green or blue (silicate based), Extended Life red/orange, DEX-COOL and yellow coolants
  • Tabs are designed to be harmless to all plastic, metal, aluminum, hoses and connections within the cooling system and will not add premature wear to cooling system components
  • Part No. 10-108 12378255

Signs of Wear & Troubleshooting:

  • Coolant discoloration is a sign of too high a concentration of seal tabs within the cooling system. This can occur if seal tabs are used repeatedly over the service life of an engine.


Good Maintenance Practices:

  • Use the proper dosage to ensure premium results. Read product instructions for direction.
  • To avoid accidental burns, ACDelco Cooling System Seal Tabs should be added to a cool radiator and cooling system. The radiator and cooling system is cool enough when the palm of the hand can be comfortably placed on top of the radiator cap, and the top radiator hose can be hand-squeezed, indicating that the system is no longer under pressure.
  • These tablets should NOT be used as a regular maintenance item after servicing an engine cooling system.



Is there a limit to how often I can use ACDelco Cooling System Seal Tabs?

  • Yes, they should not be used for more than two treatments. If the leak is not corrected after two treatments alternate, correction measures should be taken.

Can I use ACDelco Cooling System Seal Tabs in my heavy-duty or mixed-fleet application?

  • Yes, ACDelco Cooling System Seal Tabs are compatible with all current cooling system fluids.

Are there organic components in ACDelco Cooling System Seal Tabs?

  • Yes, ACDelco Cooling System Seal Tabs contain the right organic components to seal most minor coolant system leaks.

Can I use ACDelco Cooling System Seal Tabs in a larger cooling system/radiator leak?

  • No, seal tabs will only correct leaks that are minor or microscopic. If larger leaks are found, the failed part(s) should be replaced.


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