What Causes High Low Pressure and High High Pressure in Car Air Conditioning?
2 Answers
The possible causes of the fault include compressor failure, insufficient refrigerant, or a stuck-open expansion valve. Below are the specific scenarios: Pressure gauge detects low high pressure and high low pressure in car air conditioning: The cause is compressor failure. If the pressure gauge shows this phenomenon and there is no lack of refrigerant in the pipeline, but the air conditioning performance is poor, then the issue is likely with the air conditioning compressor. There may be internal leakage in the compressor, and generally, replacing the compressor can resolve the problem. Pressure gauge detects low low pressure and low high pressure in car air conditioning: The cause is insufficient refrigerant, which is a common issue. Some older cars may experience refrigerant leakage, and after inspection, simply refilling the refrigerant can solve the problem. Pressure gauge detects high low pressure and high high pressure in car air conditioning: The cause is a stuck-open expansion valve. If the car's cooling is poor and the pressure gauge shows both low and high pressures are elevated, the expansion valve may be stuck open, allowing air into the refrigeration system and mixing high and low pressures, resulting in poor air conditioning cooling performance. Replacing the expansion valve can resolve this issue.
I've encountered this issue of high low pressure and high high pressure in the car AC system before. It might be due to poor heat dissipation from the condenser or a malfunctioning fan that prevents heat from being properly expelled, causing pressure to rise on both sides. Another possibility is overcharging of refrigerant beyond the standard amount or internal system blockages obstructing airflow, which increases the compressor's workload and leads to abnormalities. That time when my car's AC started, the engine noise became louder and there was some shaking, making me worried the engine might stall while driving, so I immediately went to the repair shop. They found that the cooling fan was broken and there was an excessive amount of refrigerant oil added. After replacing the parts, the pressure returned to normal. I'd like to remind you that if the dual high pressure in the AC system isn't repaired promptly, at best it will significantly increase fuel consumption, and at worst, the compressor could be damaged beyond repair, leading to costly replacements. Always pay attention to the heat dissipation condition in the engine compartment while driving to avoid such situations.
