What are the reasons for insufficient cooling in car air conditioning?
4 Answers
Insufficient cooling in car air conditioning is caused by insufficient refrigerant. The main reason for low refrigerant levels is minor leaks in the system. When refrigerant is insufficient, the amount sprayed into the evaporator by the expansion valve will inevitably decrease. Consequently, the heat absorbed during refrigerant evaporation in the evaporator will also reduce, leading to decreased cooling capacity. A car air conditioning system generally consists of the compressor, electromagnetic clutch, condenser, evaporator, expansion valve, receiver-drier, pipelines, condenser fan, and control system. The car air conditioning system is divided into high-pressure and low-pressure pipeline systems.
Last time I drove to the seaside, even with the AC turned up to the max, it wasn't cool enough. Here's why: The most common issue is refrigerant leakage. My old buddy's car, after five years of use, had loose pipe connections that slowly leaked all the refrigerant. If the filter is severely clogged, air can't even blow out, naturally reducing cooling efficiency—I replace mine every six months. Then there are problems with the compressor and condenser. A dirty condenser leads to poor heat dissipation and reduced cooling effect, while a broken compressor is even more troublesome, requiring a complete replacement. There's also the issue of the evaporator freezing up and blocking the air ducts, or the fan not working, leading to inadequate heat dissipation. The most reliable way is to get the refrigerant pressure tested at a repair shop. Minor issues can be fixed by just adding refrigerant, while major problems might require dismantling the dashboard to replace parts.
Having worked in auto repair for so many years, I've seen plenty of AC cooling failures. First, check the refrigerant pressure - low pressure definitely indicates a leak, requiring careful leak detection, repair, and recharge. Listen to the compressor - if it's seized or making abnormal noises, it's basically done for. The condenser fins need cleaning, especially after spring when willow catkins clog them, cutting cooling efficiency in half. A clogged expansion valve also restricts refrigerant flow, and replacing it shows immediate improvement. Electrical faults like poor relay contact are common causes too - a quick multimeter test reveals the issue. A faulty thermostat misreads temperatures causing shutdowns. Professional shops use pressure gauges and computer diagnostics for reliable diagnosis.
Last time I was on the highway, the AC suddenly stopped cooling, which scared me into a sweat. After inspection, it turned out to be a refrigerant leak with a small crack at the pipe joint; replacing the seal ring cost fifty bucks. Another time in summer, the AC only blew slightly cool air, and the mechanic said it was because the cabin air filter hadn't been changed for two years and was completely clogged. Replacing it fixed the issue immediately. Now I always remember: clean the radiator fins when washing the car, check the airflow strength monthly, replace the filter annually, and test the refrigerant pressure every two years. Adding refrigerant at a roadside stall costs around eighty bucks, but remember to vacuum the system to prevent air from mixing in. The key is not to wait until the AC stops cooling completely before fixing it—small issues can be resolved for just a few hundred yuan.
