In Taiwan, the weather is humid and the driving situation is intermittent, if the air conditioning is not cold enough, it would be very annoying. The reasons for it are as followings:

In theory, the refrigerant is in a closed space, it will not reduce itself. If there’s lack of refrigerant, it’s better to check the leakage and fix it as soon as possible to save your money in advance.

Regular maintenance of the air conditioning is very important; it can save your cost in the future.

The failures of automotive air conditioning compressor or noise are very common problems; other common problems are from expansion valves or air-conditioned dry bottles, these are automotive materials consumables with certain life expectancy. The expansion valves (to regulate the flow of refrigerant) of old vehicles are often refrigerant leakage point. Just change the expansion valve, re-inject refrigerant, the air conditioning will be really cold again.

Sometimes the car owners find smelly odor (fishy or rancid), it’s useless to clean the air conditioning filter, it’s because the air conditioner evaporator is moldy. The weather in Taiwan is rather humid, so the evaporator will condense droplets of water. If you park your car in a humid place, the evaporator will be covered with all kinds of mold. Removing the evaporator to clean is usually a big project, because the evaporator is hidden in the instrument, you need to demolish a bunch of things to see.