How to Determine if a Car Compressor is Good or Bad?
3 Answers
To determine if a car compressor is good or bad, follow these steps: 1. Start the engine and maintain the speed between 1250 to 1500 RPM; 2. Connect the manifold pressure gauge to the air conditioning refrigeration system, turn on the AC switch, and set the fan to the maximum position; 3. Touch the compressor's intake and exhaust ports. A good compressor will have a cold intake and a hot exhaust with a significant temperature difference between them. If not, it is likely damaged. The working principle of a car compressor: It draws refrigerant from the low-pressure area, compresses it, and sends it to the high-pressure area for cooling and condensation. The heat is dissipated into the air through the radiator, and the refrigerant changes from a gaseous to a liquid state, increasing its pressure.
I think there's a practical way to judge whether a car's air conditioning compressor is working properly. First, start the vehicle and turn on the AC, then listen for any abnormal noises near the compressor. Normal operation should produce a slight humming sound. If you hear metal grinding or clicking noises, that's a red flag. Next, observe the cooling effect. In summer, the vent temperature at idle should be around 10°C. If there's no cool air after five minutes, the compressor might be faulty. Finally, check the pulley. When the engine is running, the compressor clutch should engage and disengage regularly. If the pulley isn't turning or the compressor is frequently cycling on and off, you can pretty much confirm a compressor failure. These simple checks can be done at home without professional tools. Also, remember to regularly check the refrigerant pressure, as abnormal pressure can accelerate compressor wear.
Last time when I got my car repaired, the mechanic taught me a few tricks. The most straightforward one is observing the AC pressure gauge. After connecting to the high and low-pressure ports, the high pressure should be around 15bar and the low pressure around 3bar when idling with the AC on. If the high pressure is too high or the low pressure is too low, it indicates abnormal compressor operation. Also, check the compressor housing – it should be slightly warm to the touch during normal operation, but not too hot to handle. If it's scalding hot or completely cold, there's likely an issue. Another simple method: open the hood, have an assistant repeatedly turn the AC on and off, and observe whether the compressor pulley engages crisply. If there's a delay of more than 1 second, consider getting it checked. While driving normally, pay attention to any pungent odors from the AC, as that could be a sign of internal compressor wear.
