What is the reason for the car air conditioning system not leaking under pressure but failing to achieve a complete vacuum?

[DiJustin]

If the car air conditioning system does not leak under pressure but fails to achieve a complete vacuum, the possible reasons are as follows: 1. Poor sealing: There may be leaks, or the sealing ring may be cracked, causing no leakage under positive pressure but leakage under negative pressure; 2. Damaged areas in the pipeline; 3. Leaking joints: During vacuum extraction, the joints may not be tightened properly, or the vacuum pump may be faulty; 4. Incorrect method: The repeated vacuum extraction method was not used during the process. Additional information: The car air conditioning system can cool, heat, ventilate, and purify the air inside the vehicle. It provides a comfortable environment for passengers, reduces driver fatigue, and enhances driving safety.