How to Determine Compressor Damage?
4 Answers
Methods to determine compressor damage: 1. Use a multimeter to measure power supply: If there is an internal short circuit in the compressor, it may not be detectable. If power is shown but the compressor does not start, and replacing the start capacitor still doesn't work, the compressor is likely damaged; 2. After the air conditioning compressor is damaged, there are obvious fault symptoms, such as winding short circuits, windings touching the casing and grounding, increased compressor vibration and noise, compressor seizing or stuck pistons, and damaged thermal protectors; 3. Measure resistance with a multimeter: There are three terminals on the compressor, labeled S, R, and C. The sum of the resistances between SC and RC should equal the resistance between RS, allowing for minor deviations. If a significant difference is detected, the compressor may be damaged.
I've been driving for over 20 years, and the main symptoms indicating a faulty compressor are poor or no cooling from the air conditioning. It's most noticeable in summer—when you turn on the AC, hot air blows out, and cooling is slow. Pop the hood, start the engine, and press the A/C button to listen for unusual noises around the compressor area: if there’s squeaking, grinding, or constant humming, the compressor is likely the issue. Observe whether the compressor clutch engages: normally, you’ll hear a 'click' when it engages, followed by the pulley spinning; if it doesn’t move or spins irregularly, it points to a clutch or compressor failure. Additionally, check for refrigerant leaks by visually inspecting pipe connections or the compressor surface for oil stains or colored traces. When these signs appear, I always advise not to push through but to head to a reliable repair shop for professional diagnostic tools, as delays can affect the entire AC system. Regular engine bay cleaning during maintenance can help prevent this issue.
As a new driver who just got my license, identifying compressor issues took some trial and error. At first, I noticed the AC wasn't cooling at all—the fan was blowing but the air felt like room temperature, which was clearly wrong. Then I started the car in A/C mode and listened near the engine bay: I heard continuous buzzing or drum-like abnormal noises, and online research confirmed these were signs of compressor failure. I tried inspecting the compressor component: check if that disc-shaped part is rotating normally—if it's stationary or vibrating abnormally, the compressor might be faulty. Here's a handy tip: after running the AC for ten minutes, feel the discharge pipe—it should be ice-cold; if it's warm, the compressor isn't working. New drivers tend to panic, so I went straight to a 4S shop or professional mechanic for confirmation—it's safer and more efficient. Don't try to save money by delaying repairs, as this could worsen the problem.
As a car enthusiast, I often troubleshoot issues myself. Here are simple steps to diagnose a faulty compressor. After starting the car and turning on the AC, listen to the engine bay: a normal compressor produces steady humming, while abnormal ones make grinding or screeching sounds. Then observe the clutch action: it should click and rotate when engaged; if not, it's faulty. Check for oil stains on the pipes? That indicates refrigerant leakage preventing compressor operation. Though I'm hands-on, repairs require professional equipment - don't risk DIY, take it to a shop.
