We take cryptocurrency — so the coins you hold can buy real hardware.Pay in crypto, spend it on real hardware. Free insured shipping worldwide over $399. Plain, unbranded boxes, sent from Germany.Free insured shipping over $399. Your rate is locked for 30 minutes once checkout opens.Rate locked 30 minutes. Every item sealed, serial-checked and covered by a 24-month warranty.Sealed, 24-month warranty.

Saved items Sign in

Supercool

Supercool ST27 A/C Leak Stop Metal 4oz

SKU CH-X4GG-C6PR8

Stops small A/C leaks in evaporators, condensers, hoses, gaskets and seals with a 4 oz liquid dye compatible with R-134a refrigerant and PAG, ester and mineral oils

  • Stops small leaks in A/C components
  • Compatible with PAG ester and mineral oils
  • Leak detection dye works with R-134a refrigerant
  • High flash point 425 Degrees F for safety
  • Boiling point 570 Degrees F handles extreme heat

Supercool ST27 Leak Stop for A/C Systems

Supercool ST27 is a 4 oz aerosol leak stop designed for automotive air conditioning systems using R-134a refrigerant. It circulates with the refrigerant to seal small leaks in evaporators, condensers, hoses, gaskets and seals. The formula is compatible with PAG, ester and mineral oils. It contains a green leak detection dye to help locate the repair area.

For DIYers fixing minor A/C leaks

This product suits vehicle owners or technicians addressing small refrigerant leaks in components such as evaporators or seals. It is not intended for large ruptures, compressor shaft seal failures or leaks in systems that have lost all pressure. Buyers needing a permanent mechanical repair or those working on systems with a different refrigerant type should look at other solutions.

Verify refrigerant type and system pressure

Confirm the vehicle uses R-134a refrigerant before application. Ensure the system still holds enough pressure to circulate the product through the circuit. Check that the compressor engages so the sealant can reach the leak points. Review safety data for the 425 °F flash point and 570 °F boiling point if working near hot surfaces.

Highlights

  • Stops small leaks in A/C components
  • Compatible with PAG ester and mineral oils
  • Leak detection dye works with R-134a refrigerant
  • High flash point 425 Degrees F for safety
  • Boiling point 570 Degrees F handles extreme heat

Specifications

BrandSUPERCOOL

Questions about this item

Does this ST27 leak stop work with R-134a systems that use PAG oil?

Yes, it is compatible with PAG, ester and mineral oils in R-134a refrigerant systems.

Will adding this 4 oz can affect the pressure readings on my existing manifold gauge set?

The product stops small leaks in evaporators, condensers, hoses, gaskets and seals without altering normal system pressures.

After injecting the green dye, how do I confirm the seal is holding at the service port?

Use a UV lamp to check for green fluorescence at connections; no glow means the leak has been sealed.

Also in this aisle

People compared these

Same shelf, same checkout — eight coins and a 30-minute rate lock.