Car AC Only Works At Night- Top Personalized Fixes In 2024

Personally, I’ve faced the challenge of my car AC only cooling effectively at night, creating discomfort during the day. Determining the root cause and implementing corrective measures has been crucial for consistent and efficient AC performance.

Why does my ac only work at night? (Short Answer)

Check the tension of the compressor’s belt. If there is a significant change in ambient temperature between day and night for you, then with heat soak the belt may be getting just loose enough that it is slipping and not turning your compressor as well as it should.

In this exploration, I’ll delve into the specific reasons why my car AC tends to cool effectively only at night and share insights on practical solutions.

How AC Works In Car?

The car’s air-conditioning system operates by altering refrigerant between liquid and gaseous states. This transition absorbs heat and humidity from the vehicle, enabling the system to release cool, dry air.

Reasons Why Car AC Only Works At Night?

Having personally encountered the perplexing issue of my car AC excelling at nighttime but faltering during the day, I delved into extensive research to uncover the underlying culprits. Here are the reasons I uncovered:

1. Refrigerant Leak:

Is car ac cold at night hot during day? The air conditioner in your automobile won’t function if there is a refrigerant leak. The reason is that the refrigerant transfers heat from your car’s interior to the exterior. The system performs less effectively when there is a leak since less refrigerant is available to carry out this task.

Refrigerant Leak
source:tracer products

The sun’s heat can make the problem stand out more during the day. It is because it’s hotter outside, so the air conditioner works longer to cool the inside of the car. The issue might not be as evident at night because the AC has an easier time cooling the car. So, ac only blows cold at night.

Also Read: Car AC Hissing Under Dash

2. Insufficient Cooling Coil or Condenser:

Why does my car ac only get cold at night? Inadequate cooling can result from a malfunctioning cooling fan positioned in front of the cooling coil or condenser, limiting proper heat dissipation.

3. Loose Compressor Piston:

A loose compressor piston occurs due to wear or improper installation, leading to reduced compression efficiency and inconsistent cold air delivery from the AC system.

Loose Compressor Piston
Source: audizine fourms

Also Read: Will Heater Work Without AC Compressor In Car

4. Clogged Valve And Dryer:

Clogged valve assembly and dryer are often caused by debris or contaminants in the refrigerant, obstructing the flow and leading to inconsistent cooling in the AC system.

Clogged Valve And Dryer
Source: Natrad

5. Compressor Clutch Issues:

Compressor clutch problems, including damaged wiring, a malfunctioning cooling control sensor, or clutch misalignment, can disrupt engagement, resulting in inconsistent cooling performance in the AC system.

Also Read: Car Hesitates When AC Is On

5. Using The Wrong Refrigerant:

Incorrect refrigerant type or contaminated refrigerant can cause damage to the AC system, leading to inefficient cooling and potential long-term harm.

6. Dirty Air Filters:

The air in your car’s air conditioning system is clean and clear of debris from the air filters. When the filters are dirty, they can stop the airflow, making the air conditioner less effective. This issue could be more noticeable during the daytime when more pollution and dust are in the air.

Dirty Air Filters
source:car and driver

The roads are less busy at night, and the air is usually better. It can hide the problem and make the car ac only blows cold air at night.

7. Low Refrigerant Levels:

Car ac is hot during the day but cooler at night? Your car’s AC may only work well with enough coolant and a low freon level. It can happen if the system leaks or the last service does not charge it enough. The air conditioner has to work more to keep the car’s interior cool when the temperature is greater during the day. Therefore, the issue might be more noticeable. At night, when it’s cooler, the AC may work better.

Low Refrigerant Levels

8. Loose Or Slipping Belt:

Car ac only blows cold air at night? AC that works at night but not during the day can also be caused by a loose or moving compressor belt. When the belt is loose or slips, the fan cannot work as well as it should, preventing cooling.

Loose Or Slipping Belt

What To Do If Your Car AC Only Works At Night?

Facing the challenge of my car AC performing optimally only at night, I’ve implemented personalized solutions for consistent cooling:

1. Check The Refrigerant Levels:

If the technician finds a leak or low refrigerant, they might need to add more to the system. Only a trained professional should do this because adding too much refrigerant can cause other problems.

Check The Refrigerant Levels

Also Read: Car AC Slows Down When Braking

2. Resolve Insufficient Cooling Coil Or Condensor:

Solve this issue by replacing the malfunctioning cooling fan to restore proper airflow, allowing efficient cooling coil and condenser operation. Confirm the AC condenser fan is operating correctly. If not, repair or replace it to prevent overheating and ensure proper AC function.

3. Fix Compressor Piston:

To resolve this issue, consult a professional mechanic to inspect the compressor. If a loose piston is found, it must be replaced to ensure optimal compression and consistent cooling performance.

4. Unclogged Valve And Dryer:

To address this issue, have a professional technician replace the clogged valve assembly and dryer to restore proper refrigerant flow, ensuring consistent and efficient cooling.

5. Resolve Compressor Issues:

  • Check and repair any damaged wiring or connections related to the compressor clutch.
  • Inspect the cooling control sensor and replace it if it’s malfunctioning.
  • Adjust the compressor clutch or replace it if necessary to ensure proper engagement.
Resolve Compressor Issues
Source: dubizzle

Also Read: Gurgling Sound When AC Is On In Car

6. Drain Incorrect Refrigerant:

To rectify this issue, drain the incorrect or contaminated refrigerant and replace it with the appropriate refrigerant type, ensuring cleanliness to avoid further system damage. You may want to have a professional check and possibly recharge your AC system with the appropriate refrigerant (R12 or R134a)

7. Replace Dirty Air Filters:

AC works fine at night but not during the day? If the air filters are dirty, you can switch them out to improve the AC. It is a cheap fix that can significantly affect how well the air conditioner works.

 Repair Electrical Problems
source:service cadillac

8. Ensure Radiator Fans:

Ensure radiator fans operate optimally, and remove any obstructions obstructing condenser airflow to maintain efficient cooling, especially when the car is stationary.

Also Read: Can A AC Compressor Stop A Car From Starting

9. Check Belt:

Does air conditioner only work at night? Verify the tension of the compressor’s belt. Suppose the temperature in your area varies significantly between day and night. In that case, heat soak may cause the compressor’s belt to become slightly loose enough to slip and stop turning as effectively.

Check Belt

Tips for Adjusting Cabin Temperature and Caring for Your Car’s A/C:

  • Ventilate the hot air in the cabin by opening windows after parking in the sun.
  • Start the engine and use the A/C on max to cool the cabin, then reduce it to maintain the desired temperature.
  • Use cabin recirculation mode to cool the cabin faster.
  • Keep air vents clean to ensure proper airflow.
  • Avoid using A/C to hit the front windshield on humid days to prevent fogging.
  • Maintain a clean area under the front seat for better airflow.
  • In cold weather, use the H1 fan speed position briefly to reduce humidity and defrost windows.
Source: GoMechanic

Also Read: Can I Sleep In My Car With The AC Running

Car AC Stopped Working Overnight:

Your car’s AC stopped working most likely because of a freon leak or a bad compressor. Though these causes are the simple to spot reasons for your AC not working inside your car, it might be anything as simple as a dirty cabin filter or a bad belt.

Why Does My AC Work Better At Night?

An AC that struggles to cool effectively during the day but performs well at night may indicate low refrigerant levels. Sufficient refrigerant for minimal cooling needs at night contrasts with daytime demands, revealing a potential issue with refrigerant levels.

Car AC Only Works In Shade:

Air conditioners are rated based on heat flow. In shaded areas, the lower heat flow allows the AC to efficiently cool, as it can handle the reduced heat input. However, in direct sunlight, higher heat flow exceeds the AC’s capacity, making it challenging to keep up with the increased heat influx.

Also Read: Can I Drive My Car Without AC Compressor

Car AC Only Works When Cool Outside:

A malfunctioning cooling fan can contribute to your car AC issues, especially in hot weather. Weak or non-cooling airflow may result from issues like a broken electrical circuit, faulty capacitor, damaged contactor coil, or a short-circuited fan motor. These components impact the fan’s effectiveness and, subsequently, the overall performance of your car’s AC system.

1. Can The Engine’s Heat Effect My Car’s AC Performance?

Yes, the engine’s heat may affect how well the air conditioner performs since it can raise the temperature under the hood, which makes it more difficult for the AC to cool the air.

2. Can Weather Conditions Affect My Car’s AC Performance?

Does car air conditioner only work in cold weather? Yes, the outside temperature can impact a car’s air conditioner’s effectiveness. For instance, even if the AC functions well, high humidity can make the air seem warm and unpleasant.

3. Can My Car’s AC Be Affected By The Position Of The Sun?

Yes, the way a car’s AC works can be affected by where the sun is. It might get hotter inside the car and more difficult for the air conditioner to chill when the sun shines directly on the window. It can be reduced by utilizing a sun shade or sitting in the shade.

4. Why Does My AC Work At Night But Not During The Day?

The unit may require coil cleaning, and a malfunctioning condenser fan motor could be shutting off in warmer daytime conditions. Operational conditions are more favorable at night.

5. Why Is My Car AC not Cooling During The Day?

A failing compressor or freon leak is a common reason for ineffective car AC. Simple issues like a bad belt or dirty cabin air filter can also contribute to cooling problems

6. Why Is My Car AC cold In The Morning But Not In The Afternoon?

A potential A/C system leak could result in warm air in the afternoon, as insufficient refrigerant hampers the cooling process

7. Why Is My AC Not Working During The Day?

A dirty air filter can impede airflow, reducing cooling efficiency and even causing system shutdown. Regular filter checks are essential for optimal AC performance.

8. Why Is My Car AC Not Working When Its Hot Outside?

In hot weather, a non-functioning car AC may stem from a broken compressor or a disengaged clutch. The compressor, crucial for refrigerant circulation, can fail due to overheating, insufficient lubrication, or low refrigerant levels.

9. Why Does My Car AC Compressor Shut Off When Hot?

The compressor may shut off due to overheating, possibly caused by dusty condenser coils, a malfunctioning fan motor, or insufficient airflow. Low refrigerant levels can also trigger the compressor shutdown.

10. Why Does My Car Heat Up When The AC is On?

The cooling system works to cool the AC condenser, leading to overheating. Causes include clogged condenser fins, a faulty condenser fan, or an ineffective water pump disrupting proper coolant circulation.


If your car’s air conditioner only works at night but not during the day, there might be a refrigerant leak, a filthy air filter, an electrical issue, a loose belt, or low refrigerant levels. To identify the problem and recommend the best course of action for fixing it, it is imperative to have a qualified specialist examine the system.

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