What causes high low pressure but normal high pressure in the new Santana's air conditioning system?
2 Answers
New Santana's air conditioning system showing high low pressure but normal high pressure is caused by a faulty or damaged expansion valve. Automotive air conditioning system: The automotive air conditioning system is a device that cools, heats, ventilates and purifies the air inside the vehicle compartment. It provides a comfortable environment for passengers, reduces driver fatigue, and improves driving safety. The air conditioning system has become one of the indicators for measuring whether a car is fully equipped. Normal pressure values: The normal high pressure of an automotive air conditioning system should be 1.3-1.7MPa (13-17kg/cm2 or Lbf/in2). The normal low pressure should be between 0.1-0.25MPa (1-2.5kg/cm2 or 15-35Lbf/in2).
The high low pressure but normal high pressure in the new Santana's AC system is indeed puzzling. A common cause is overcharging of refrigerant, which creates an imbalance in system pressure and leads to elevated readings on the low-pressure side. Additionally, the expansion valve might be faulty—either stuck open or partially blocked—affecting refrigerant flow into the evaporator. A dirty or slightly obstructed condenser can also cause similar symptoms where high pressure stays normal while low pressure rises abnormally. I recommend using professional gauges to test; standard low pressure should range between 20-40 PSI. Exceeding this requires checking refrigerant levels or cleaning the system. Regular AC maintenance like cleaning filters and inspecting pipes for leaks prevents such issues. Neglecting repairs reduces cooling efficiency, wastes fuel, damages the compressor, and escalates repair costs over time—visit an authorized service center promptly.
