Reasons for High Pressure in a Car A/C System

by Jennifer Simon

Mechanics often misdiagnose high-pressure gauge readings in a car's air-conditioning system. Although mechanics tell owners that the high pressure is due to a problem with the accumulator or evaporator that is not likely the case. Most high-pressure readings are a result of the freon or refrigerant not cooling adequately. Insufficiently cooled freon automatically causes the pressure to increase.

Issues with the Condenser

The air-conditioner's condenser is responsible for receiving high-pressure and temperature refrigerant from the compressor. It is designed to dispel the heat and cool the refrigerant or freon. The condenser should be thoroughly cleaned and no debris should be present. Also, the condenser should be checked to ensure that there is not an obstruction blocking the condenser's air flow.

Loose Fan Shrouds or Air Dams

High pressure can be the result of loose fan shrouds or air dams. The fans and shrouds should be mounted securely in order to work effectively. Tighten any of the appliances that are not positioned correctly or tightened adequately. Fans and shrouds are designed to run at specific speeds, so determine if any of the fans are running at a reduced speed. Replace any of the fans that are malfunctioning in order to restore the air-conditioning system's cooling abilities. The shrouds and fans are directly related to the refrigerant cooling process. Once the cooling issue is resolved the high-pressure gauge should return to normal.

Engine Cooling Problems

The engine should also be checked for overheating issues. An overheating engine radiator can cause the air-conditioning system's pressure to increase significantly. Heat from the radiator transfers to the condenser and cause the pressure to rise due to the warmer refrigerant. It is possible the space between the radiator and the condenser has become clogged with debris. The entire cooling system should be checked and cleaned thoroughly in order to solve the high-pressure issue.

About the Author

Jennifer Simon has been a copywriter since 2007, a copyeditor since 2004 and currently teaches English Composition at Full Sail University. Her edited articles have appeared in "The Washington Post," "The Huffington Post" and "The Network Journal." Simon has a Master of Arts degree from Duquesne University with a focus in modern English grammar, linguistics and editing.