Why does my car AC only cool when driving Subaru?
It's a frustrating experience: you start your Subaru on a hot day, turn on the air conditioning, and notice that it only blows cool air when you're driving. When idling, the air becomes warm or less effective. This issue is more common than you might think and can stem from several underlying causes. In this article, we'll explore the reasons behind this problem and what you can do to fix it.
How Your Car's AC System Works
To understand why your Subaru's AC might only cool while driving, it's important to know how the system operates. Your car's air conditioning system relies on several key components, including the compressor, condenser, evaporator, and refrigerant. The compressor, powered by the engine, circulates refrigerant through the system to remove heat from the cabin air. When the car is idling, the engine runs at a lower RPM, which can affect the performance of the AC system.
Common Reasons for AC Cooling Issues
Here are some of the most common reasons why your Subaru's AC might only cool when you're driving:
- Low Refrigerant Levels: If the refrigerant is low, the AC system may struggle to cool the air effectively, especially at lower engine speeds.
- Faulty AC Compressor: The compressor is responsible for pressurizing the refrigerant. If it's worn out or malfunctioning, it may not work efficiently at idle.
- Condenser Fan Problems: The condenser fan helps dissipate heat from the refrigerant. If the fan isn't working properly, the AC system may overheat and lose efficiency when the car isn't moving.
- Clogged Condenser: Dirt, debris, or damage to the condenser can restrict airflow, reducing the system's ability to cool the air.
- Idle Speed Issues: If your engine's idle speed is too low, it may not provide enough power to the AC compressor, leading to reduced cooling performance.
Each of these issues can contribute to your AC's poor performance when idling. Identifying the root cause is essential for resolving the problem.
Steps to Diagnose and Fix the Problem
If you're experiencing this issue, follow these steps to diagnose and address the problem:
- Check Refrigerant Levels: Have a professional check the refrigerant levels in your AC system. Low refrigerant is a common cause of cooling issues.
- Inspect the Compressor: A mechanic can test the compressor to ensure it's functioning properly at all engine speeds.
- Examine the Condenser Fan: Make sure the fan is running when the AC is on. If it's not, the fan motor or relay may need to be replaced.
- Clean the Condenser: Remove any debris or dirt from the condenser to improve airflow and cooling efficiency.
- Check Idle Speed: If your engine's idle speed is too low, a technician may need to adjust it to ensure the AC system gets enough power.
By following these steps, you can pinpoint the issue and restore your Subaru's AC to full functionality.
When to Seek Professional Help
While some of these steps can be performed at home, others require specialized tools and expertise. If you're unable to resolve the issue on your own, it's best to bring your Subaru to a trusted auto repair shop. At Kevin's Autos, we have years of experience diagnosing and repairing AC systems in all makes and models, including Subarus. Don't hesitate to reach out for professional assistance!
In conclusion, an AC system that only cools while driving is often a sign of an underlying issue with refrigerant levels, the compressor, or other components. By addressing the problem promptly, you can ensure your Subaru's AC keeps you cool and comfortable, no matter where the road takes you.
Frequently Asked Questions
Why does my AC get warm when I stop driving?
Usually this is caused by a low charge. The high side and low side pressures are greater when driving causing the compressor to stay engaged longer. If the system is low, the compressor is going to have longer off times at idle resulting in warmer air.
How to tell if freon is low in AC car?
One of the most obvious signs that your vehicle needs a Freon recharge is that your vehicle will be blowing warm air, even after your vehicle has been running for some time. If your refrigerant gets too low, there will simply not be enough “coolant” to cool the air as it is passed through your evaporator coil.
How do I know if my Subaru AC compressor is bad?
Common Signs of a Failing Subaru AC Air Compressor
- High Cabin Temperatures. One of the very first signs of a failing compressor is the failure of the air conditioner to blow cold air as it used to do.
- Loud Noise.
- Compressor Clutch Not Moving.
Why is my car AC not cooling when idling?
If your car's AC isn't cooling while idling, several potential issues could be at play. Low refrigerant levels, a faulty compressor, condenser problems, cooling fan issues, engine overheating, or a dirty cabin air filter may be to blame.
How do I know if my AC condenser is clogged?
This article will discuss five signs your AC condenser needs repair.
- Bad Smell. When an AC condenser unit stays for long without maintenance, it may start emanating a foul odor.
- Lack of Cool Air.
- Burning Smell.
- Lack of Airflow.
- Overheating While Idling.
- Bad Smell.
- Lack of Cool Air.
- Burning Smell.
How to tell if Freon is low in AC car?
One of the most obvious signs that your vehicle needs a Freon recharge is that your vehicle will be blowing warm air, even after your vehicle has been running for some time. If your refrigerant gets too low, there will simply not be enough “coolant” to cool the air as it is passed through your evaporator coil.
Why does my car AC stop working when it gets hot?
Your Compressor Might Be Broken, or Its Clutch Isn't Engaging. If refrigerant is the lifeblood of your A/C system, the compressor is the heart since its job is to circulate refrigerant through the system. Overheating, lack of lubrication, and low refrigerant levels are all common causes of compressor failure.
How long do Subaru AC compressors last?
Does my SubaruForester AC compressor need replacing? In many cases, the AC compressor can typically endure the lifespan of the Subaru Forester without needing replacement. However, the likelihood of failure increases after surpassing 150,000km.
Why does my car AC only cool when driving?
Likely low refrigerant in the system. When you are idling there is not enough refrigerant moving through the system to cool the air flowing through it.
Why does my AC stop working when my car is parked?
When the car is not in motion, the only airflow the condenser coil receives is through the engine fan which is a considerable drop in the cooling compared to what it was at 30 mph. This leads to increased temperatures of the refrigerant and overall reduced capacity.
