What Causes Normal Low Pressure but Low High Pressure in Car Air Conditioning?
2 Answers
When a car's air conditioning system exhibits low low-side pressure and normal high-side pressure, it is typically caused by a malfunction or failure of the air conditioning compressor. Below is a detailed explanation of this issue: 1. For compressor failure leading to normal low pressure but low high pressure, the solution generally involves replacing the air conditioning compressor with a new one. 2. Due to the cramped and compact space around the car's air conditioning compressor, disassembly is quite inconvenient. Additionally, temporary recovery of the refrigerant is required, making the process labor-intensive. It is recommended to have this service performed at a 4S dealership.
I've encountered this situation quite often during car repairs, and the most common cause is a faulty AC compressor. If the internal components of the compressor are worn or the valve plates are damaged, the compression efficiency decreases, and the high pressure will definitely fail to rise. Additionally, if the expansion valve is stuck in the open position, it can cause the same issue by allowing too much refrigerant flow, naturally preventing the high pressure from building up. It's unlikely to be due to excessive condenser cooling or blockages in the system, as these conditions would actually cause the high pressure to rise. Honestly, when the high pressure is low, there's usually no need to check for blockages in the pipelines. If your car is experiencing this issue, I recommend immediately checking the compressor's efficiency. When driving, avoid running the AC at maximum fan speed for extended periods, as the excessive load can shorten the compressor's lifespan. Regular AC maintenance can help avoid major repairs.
