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Problems of Using A/C Sealant

A/C sealants, also known as stop leak, are designed to be a ‘quick fix’ to seal leaks in the A/C system. The sealant is activated when it reacts with oxygen and/or moisture.

However, sealants can crystallize in the system, which can cause more harm to the A/C system. While the leak is covered by the sealant, this seal could possibly only last a few months. Furthermore, the sealant will remain in the system, and it could react with moisture already in the system, which comes from low refrigerant, causing major issues to the whole A/C system.

Listed below are ways in which a sealant can negatively impact the A/C system:

  1. Crystallization can happen in the orifice tube or expansion valve (where moisture is present) clogging or restricting the A/C system.
  2. The crystallization restricts the oil flow back to the compressor causing compressor failure.
  3. If a technician begins the process of recovering the system (without knowledge of the crystallization), the system can be contaminated , thus causing complete failure of the recovery system as well as the A/C system.


Pictured above: Solidified sealant trapped in the cylinder and cylinder head.



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