Why is the low pressure of car air conditioning too high?

[VanSkylar]

There may be several reasons for the high low pressure in car air conditioning: 1. Low pressure drop: If the high pressure rises after adding some oil and the low pressure drops, it may be due to a blocked expansion valve. This could be caused by a failed dryer (receiver-drier), with dirt or possibly metal particles from compressor wear entering the expansion valve and causing blockage. It is recommended to replace the expansion valve and dryer, and perform a no-disassembly cleaning of the air conditioning system pipeline. A failed temperature sensing switch may keep the valve in a normally closed state. Replace the expansion valve and dryer. 2. Low pressure rise: If the high pressure rises slightly after adding oil and the low pressure also rises, there may be air in the pipeline or poor sealing allowing air to enter. The system should be rechecked for leaks, evacuated, and refilled with refrigerant. Blockage in the pipeline system, a blocked or faulty expansion valve should be addressed by replacing the expansion valve and cleaning the pipeline. Another typical symptom is heavy condensation or frost (ice) on the low-pressure pipe. Replace the expansion valve.