What Causes High Low Pressure and Low High Pressure in Car Air Conditioning?
3 Answers
Car air conditioning compressor fails to generate the required displacement, leading to expansion valve malfunction; lack of cooling is due to insufficient refrigerant in the compressor. Compressor fails to generate the required displacement: When encountering high low pressure and low high pressure conditions, it is necessary to seek repairs and have professionals identify all faults. If the compressor's high-pressure pipe shows signs of blackening, replacement is required until the air conditioning operates at normal pressure. Insufficient refrigerant: Low refrigerant levels can be addressed by adding more refrigerant. Compressor faults require checking for blockages or leaks. Blockages occur due to excessive dirt and require cleaning, while leaks necessitate repair of the leakage points.
I found my car's air conditioning isn't cooling well, and the check revealed high low pressure and low high pressure, which is really annoying. This could be due to compressor issues, such as internal leaks or wear, causing insufficient refrigerant compression that leads to elevated low pressure. It might also be an expansion valve blockage or malfunction, preventing proper gas flow and resulting in decreased high pressure. Additionally, air or moisture might have entered the system, disrupting pressure balance, or insufficient refrigerant could cause this, turning my car into a sauna. Last summer, I faced a similar situation—delaying repairs nearly ruined the compressor, and fixing it was expensive. I think it's best to take it to a professional shop for pressure testing; their diagnostic tools can quickly pinpoint the issue, avoiding a roadside breakdown in the heat.
When driving long distances, it's common to encounter abnormal air conditioning pressure. Low pressure being high while high pressure is low mostly indicates compressor or expansion valve failure, causing refrigerant flow disorder and pressure imbalance. It could also be due to loose pipe connections leaking gas, preventing high pressure from building up; or the condenser fan not spinning, leading to poor heat dissipation which also lowers high pressure. My mechanic friend taught me to use a simple pressure gauge for self-checking – if readings are abnormal, address it promptly. Don't cut corners by randomly adding refrigerant yourself, as incorrect refilling can worsen the situation. Get it inspected at a professional shop ASAP, otherwise the longer you drive, the more fragile the system becomes, and major repairs can be shockingly expensive.
