What is the solution for car air conditioning blowing hot and cold intermittently?
3 Answers
For the air conditioning to operate properly, both the internal and external units need to work in coordination. You can check if the starting capacitor of the external unit's compressor is damaged, and replace it if necessary. If the filter or evaporator is too dirty, it can easily lead to poor ventilation and heat dissipation, causing the compressor to shut down due to thermal protection. Therefore, regular cleaning is essential to maintain cleanliness. Air conditioning cooling requires an adequate amount of refrigerant, commonly known as Freon. If the temperature inside the car fluctuates between hot and cold, check whether the refrigerant in the air conditioning cooling system is sufficient. If it is low, simply add more refrigerant.
Last time I encountered the AC blowing hot and cold randomly, which was really annoying. Turned out the cabin air filter was clogged like a trash can. After removing the glove compartment and replacing the filter, the airflow improved immediately. A faulty temperature sensor can also cause this - I've seen it several times during repairs, especially in older cars. Refrigerant leaks are even more troublesome; frost on the low-pressure pipe is a telltale sign. Remember to rinse the condenser during car washes - dirt buildup affects heat dissipation. Also, check if the cooling fan is running properly; if it's stuck, heat dissipation fails. If the compressor clutch slips during hard acceleration, cooling becomes intermittent. I suggest first spending a few bucks to replace the filter. If that doesn't work, then check the sensor and refrigerant pressure.
As a veteran taxi driver with 15 years of experience, here are some practical tips for you: Don't turn on the AC immediately after starting the car in the morning; use the external air circulation for two minutes before cooling. Switch to internal air circulation at red lights to maintain stable cooling. A loose compressor belt can cause slippage—check if the tachometer needle jumps. Replace the expansion valve if it's clogged; over time, debris accumulates like rust in a pipe. A faulty air door actuator is often overlooked, causing unstable airflow and fluctuating temperatures. I always keep a gauge in my car to check refrigerant levels; if the pressure is below 2 bar, it must be refilled. When washing your car monthly, focus on rinsing the front grille—blockages from leaves and insect debris can have a big impact.
