7 Symptoms of a Bad A/C Expansion Valve
Is your car’s air conditioner blowing warm air or your car interior feeling cold? The problem could be a faulty A/C expansion valve. Learn the most common symptoms of a faulty A/C expansion valve, what causes it to fail, and what to expect in terms of replacement costs.
The Purpose of an A/C Expansion Valve
The A/C expansion valve is found in your vehicle’s air conditioning system. The valve’s purpose is to control the amount of refrigerant liquid that flows through this system. Too much refrigerant will make the evaporator core too cold and eventually freeze, just like too little refrigerant will make the core too hot and overheat.
To prevent both scenarios, the A/C expansion valve controls the flow rate based on the evaporator temperature and the need for cool air from the system.
How an AC Expansion Valve Works
The A/C expansion valve controls this refrigerant flow via a rod that sits within it. The rod can move up and down to close or open a passage for the refrigerant. In other words, the valve calculates how much refrigerant needs to flow through the passages based on the demands placed on it.
This is true not only when the driver sets the temperature low, but also when the outside temperature is naturally high. With higher thermal resistance in the environment, the air conditioning system needs more refrigerant to create a cool temperature inside the vehicle cabin.
Symptoms of a faulty car air conditioner expansion valve
When the expansion valve stops working properly, the signs are easy to see, especially on hot summer days. The most common symptoms of a faulty air conditioner expansion valve are:
1) Warm air coming out of the vents
The most noticeable symptom of a faulty air conditioner expansion valve is the rush of warm air coming out of the vents when you turn on the air conditioner. This obviously means that there is not enough refrigerant in the evaporator core.
Most people find this problem out at the worst possible time, around mid-August.
2) Frost on the Vents
Your car’s air conditioning system should never get so cold that it causes frost on the vents. If your car’s vents are covered in ice, it’s a sign that the evaporator is frozen.
The air coming out of the vents is also much colder than usual. You might think this is a good thing, but if it continues, it will affect the performance of the entire system. In this situation, it seems that the expansion valve of the air conditioner was not able to prevent the overflow of the cooling water into the core.
3) Air conditioner compressor always on
In this way, if the expansion valve of the air conditioner is stuck open and cannot close properly, refrigerant is continuously pumped into the air conditioner. The compressor continues to pump coolant without stopping.
If this continues for a long time, it puts more and more strain on the compressor. When this happens, other components of your air conditioner start to wear out and fail.
4) Uneven Airflow
A faulty A/C expansion valve can cause uneven performance in regulating the flow of coolant throughout the system. When this happens, the air coming out of your vents may be too cold or too warm. The air temperature can fluctuate between different temperatures from hour to hour. Some may mistakenly think that the system is normal and it will only take a few minutes to repair itself. However, if the air changes from cold to warm again, you should check your air conditioner expansion valve immediately.
5) Air Conditioner Failure
If you notice any of the symptoms on this list but continue to ignore them, eventually the entire air conditioner will fail. That is, some of the important parts of the air conditioner will be damaged. Even if you then replace the expansion valve of your air conditioner, other broken parts will also need to be repaired.
6) Air conditioner is noisy
If the expansion valve is defective, the air conditioner may make strange noises such as “rattling,” “whooshing,” or “whispering” while operating. These strange noises may be noticeable when you first turn on the system or when accelerating. The abnormal noises may be due to the valve not opening or closing properly or debris clogging the valve. If you simply ignore the problem, these abnormal noises may indicate a worsening of the problem and may cause serious damage to your air conditioning equipment.
7) Moisture or Refrigerant Leaks
A damaged expansion valve can cause a refrigerant leak, which may result in a visible moist or oily residue around your air conditioning components or a puddle of water under your vehicle.
The seal in the expansion valve can wear out over time, allowing refrigerant to leak. In some cases, a defective expansion valve can cause the system to operate at the wrong pressure, stressing other components and causing leaks elsewhere in the system. If you notice any of the following signs of a leak: If you notice puddles of water underneath your car, or if you experience a persistent loss of cooling performance, have your A/C system inspected and repaired immediately Not only are coolant leaks harmful to your car, they’re also bad for the environment.
