Why does the car air conditioner fluctuate between hot and cold?

2 Answers
DeEli
07/25/25 3:42am
The reasons for a car air conditioner fluctuating between hot and cold include a damaged compressor capacitor, a dirty filter, or insufficient refrigerant. Below are detailed explanations: 1. Damaged compressor capacitor: The operation of the air conditioner requires coordination between the internal and external units. If the car air conditioner fluctuates between hot and cold, check whether the external unit's compressor starting capacitor is damaged. 2. Dirty filter: If the air conditioner has not been cleaned for a long time, it may also cause fluctuations between hot and cold. A dirty filter or evaporator can lead to poor ventilation and heat dissipation, triggering the compressor's thermal protection shutdown. 3. Insufficient refrigerant: Air conditioning requires refrigerant, commonly known as Freon, to cool. If the temperature inside the car alternates between hot and cold, check whether the refrigerant in the air conditioning system is insufficient.
Was this review help?
16
2
Share
DeLeah
08/10/25 5:04pm
I've been driving for over ten years, and I hate it the most when the air conditioning keeps fluctuating between hot and cold. Common causes include insufficient coolant or air leaks, an unstable compressor can make the cold air intermittent, and a faulty temperature sensor can also mess things up. Dirty or stuck fan blades can affect airflow, making it feel like it's stuttering. It's recommended to first check the system pressure; a simpler way is to use a refrigerant detection tool to measure it. If it's low, top it up or get a professional to fix it. An air conditioner that fluctuates between hot and cold not only affects driving comfort but also increases the risk of drowsiness on summer highways, so don't delay—early inspection and maintenance are key. Last time my car had a similar issue, it was caused by corroded wiring connectors. It was simple to fix but still wasted a lot of time.
Was this review help?
8
1
Share
Expand All
More Forum Discussions

What to Do When the Car Won't Start After Overheating and Stalling?

There are several reasons that can cause the engine's water temperature to rise excessively or even "boil over," such as damaged electronic components in the cooling system (thermostat, cooling fan), poor radiator performance, or insufficient coolant. Here is relevant information: 1. Causes: Damaged electronic components in the cooling system (thermostat, cooling fan), poor radiator performance, or insufficient coolant. 2. Solution: Pull over to the side of the road, but do not turn off the engine immediately. Since the coolant temperature is already very high and its cooling capacity has reached its limit, turning off the engine right away would stop the circulation of the boiling coolant. Let the engine idle for a while first, as the continuously circulating coolant can still help mitigate the impact of high temperatures on the engine.
12
3
Share

How to open the fuel tank of Borgward BX5?

There are three methods to open the fuel tank cap of the Borgward BX5: 1. Press method. After turning off and parking the car, the refueling attendant can directly press the fuel tank cap to open it. However, please note that when the vehicle is unlocked and not refueling, the central locking must be engaged; otherwise, the fuel tank cap can be opened. 2. Mechanical key method. The driver needs to exit the vehicle and use the key to open it. 3. Interior switch button method. This is currently the most common way to open the fuel tank cap. The location of the interior switch varies among different models—some are located below the left side of the driver's seat, some on the left front door panel or the center console, but all have a fuel pump-like symbol. Note that this method makes it easy for drivers to forget to turn off the engine before refueling.
10
0
Share

How to Start a Hyundai Car When the Key Fob Battery is Dead?

Here are the methods to start a Hyundai car when the key fob battery is dead: 1. You can use the mechanical key to start the car. 2. If the key is a proximity key, after pulling out the mechanical key from the top of the key fob, you will see a keyhole on the door handle. After opening the door, press the proximity key against the push-button start switch to start the vehicle. However, this is only an emergency method. Below is some information about Hyundai cars: Taking the Hyundai Elantra as an example, its body dimensions are 4570mm in length, 1775mm in width, and 1445mm in height, with a wheelbase of 2700mm. Its front face still adopts the typical family design, with fewer sharp lines and more rounded contours, making it look more harmonious and balanced. The grille is fully chrome-plated, giving it a more stylish and upscale appearance.
19
5
Share

What is the wheelbase of the Nissan Lannia?

The wheelbase of the Nissan Lannia is 2.7 meters. Here is some information about the Nissan Lannia: 1. Exterior: It retains some of the design elements of the current model, featuring a fastback design, a short and high rear end, and an overall body posture that appears to be in a diving stance. The large V-shaped chrome decoration gives it a highly recognizable appearance. The body dimensions are 4683*1780*1465mm in length, width, and height, with a wheelbase of 2700mm. 2. Configuration: The new Lannia is equipped with the "Nissan Connect" system, which supports intelligent voice control functions, providing a more convenient driving experience. The system offers services such as in-car navigation, in-car Wi-Fi hotspot, remote real-time monitoring, vehicle condition monitoring, traffic violation queries, electronic fence, and weather forecasts. 3. Interior: The overall interior leans towards a sporty style, influenced by the wheelbase and width.
8
2
Share

How to Replace the Bora's Position Light?

Steps to replace the Bora's position light are as follows: 1. Open the hood and locate the headlight dust cover. 2. Open the dust cover, find the position light socket, and gently pull out the position light with a bit of force. 3. Remove the bulb from the socket and compare the two bulbs. 4. Insert the new LED bulb into the socket, ensuring proper alignment. 5. After installation, turn on the switch. If it doesn't light up, remove the bulb and reinsert it in reverse, as this bulb has polarity. 6. Finally, carefully reinstall the position light, making sure it's securely inserted to prevent it from falling into the headlight. DIY operation is not recommended.
12
0
Share

Which Side is the Driver's Seat in Canada?

Canadian drivers sit on the left side. Here is relevant information: Specific details: Canada used to drive on the left but switched to right-hand traffic in 1946, so Canada now follows right-hand traffic rules. In left-hand traffic systems, drivers sit on the right, whereas in right-hand traffic systems, drivers sit on the left. Therefore, Canadian drivers sit on the left side while Canada follows right-hand traffic. Additional information: Reasons why cars drive on the right with drivers seated on the left: Drivers can maintain control of the steering wheel with their left hand while using their right hand to perform complex actions such as gear shifting and operating the dashboard. When humans are in rapid motion and detect danger ahead, they instinctively lean or turn left to protect the position of the heart.
19
5
Share
Cookie
Cookie Settings
© 2025 Servanan International Pte. Ltd.