A/C Expansion Valve (How it Works, Failure Symptoms, and Replacement Cost)

Last Updated on November 1, 2019

Air conditioning is essential for the comfort of every trip you take in your vehicle, particularly in parts of the world where the weather is hot for a greater portion of the year. Yet many people do not understand how it works, leaving them with expensive car repair costs.

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Learning about what an A/C expansion valve does and its common failure symptoms will help you to keep costs down if it ever comes time to replace it.

How an A/C Expansion Valve Works

The main function of an air conditioner expansion valve is to remove pressure from the liquid refrigerant in the system. This allows for expansion, and then converts the refrigerant from liquid to vapor inside the evaporator. In addition, the valve controls the refrigerant flow, called metering.

Inside of the valve is a moveable rod that moves up and down. This enables it to open and close the passageway inside, allowing refrigerant to enter, or not.

At any given time it can accurately meter the precise amount of refrigerant that’s needed. As you know, some days it’s hotter than others, so this control is needed to adjust the A/C, otherwise you’re going to be too uncomfortable in your car.

In fact, failure of the expansion valve is one of the top reasons that your A/C has stopped functioning well, as it can wear out over time.

Bad A/C Expansion Valve Symptoms

Generally, the first time you get a clue that something is wrong with your air conditioning it’s through a symptom of a faulty A/C expansion valve. That first symptom is often with your A/C blowing warm air, instead of cool. There may also be frost on the A/C evaporator, or it may form on the vents.

Another indicator is when your A/C compressor is constantly running. This is because the expansion valve will get stuck and fail to open. This means that the compressor will continue to pump refrigerant into the A/C’s system, even when you already feel cold.

At this point, it’s recommended to take your vehicle to a vehicle air conditioning place to have it repaired. Unfortunately, the valves are often deep within your vehicle’s A/C system and it’s not as simple as opening a door and putting gas in your vehicle.

Related:  Symptoms of a Bad A/C Condenser

A/C Expansion Valve Replacement Cost

For replacement parts, we recommend: PartsGeek.com

Usually, replacing your car’s A/C expansion valve will cost you around $150 to $350. The valve itself will set you back between $50 to $150 in most cases while the labor will run about $100 to $200, so it’s important to get a couple quotes first.

Now that you understand what can go wrong with your car’s A/C expansion valve, you can get straight to business and ask your local repair shop what exactly the costs will be, instead of paying for expensive labor simply to “discover” what is wrong with your A/C.


1 thought on “A/C Expansion Valve (How it Works, Failure Symptoms, and Replacement Cost)”

  1. We have a 2005 Honda Accord Hybrid, the A/C is blowing warm air a shop removed the old freeon and put new in but it still blew out warm air. What could it be…


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