Can a dirty filter cause AC to not cool?

If the car air conditioner filter is not cleaned or replaced for a long time, excessive accumulation of dust will indeed reduce the cooling efficiency or even result in no cooling, as a clogged filter obstructs airflow and diminishes the heat exchange efficiency of the evaporator. It is best to inspect the filter every 10,000 to 15,000 kilometres or annually; in areas with high dust levels, the interval should be shortened to every 5,000 kilometres. If the filter surface appears significantly blackened or has poor light transmission, replace it immediately with an original equipment part (priced between RM30 and RM150), as inferior filters may cause secondary contamination. This can be fully resolved through professional steam cleaning (costing approximately RM80 to RM200). To effectively prevent microbial growth, regularly turn off the AC and set the fan to high speed to dry condensation before shutting down the engine. If abnormal cooling is accompanied by odors, first check the filter condition before evaluating refrigerant pressure or compressor operation to avoid system damage from unnecessary refrigerant replenishment.