What Causes the Engine to Shake When the Air Conditioner is Turned On?
2 Answers
Air conditioner is turned on, the engine shakes for the following reasons: 1. Faulty air conditioning compressor: If the air conditioning compressor malfunctions, it can cause excessive pressure, leading to shaking when the air conditioner is in use, which in turn affects the engine, causing resonance and shaking; 2. Throttle valve blockage: If the throttle valve is blocked, it affects the engine's air intake function, leading to poor ventilation and causing abnormal shaking; 3. Engine carbon buildup: Severe engine carbon buildup is a major cause of engine shaking. If the carbon buildup is not effectively cleaned, it can interfere with normal fuel combustion, resulting in abnormal engine shaking.
I think it's quite common for the engine to shake when the AC is turned on. My old car had the same issue. It's mainly because the compressor adds an extra load to the engine when it starts, like suddenly stuffing a watermelon into your backpack while you're running. Back then, I checked three things at the repair shop: first, the engine mounts were worn out—cracked rubber can't absorb vibrations; second, the throttle body had thick carbon deposits, affecting air intake efficiency; and third, the spark plugs hadn't been replaced after over 80,000 kilometers, causing unstable ignition. The most noticeable symptom was the steering wheel vibrating when idling at a red light with the AC on. I suggest first checking the engine RPM—normally, it should rise by about 200 RPM when the AC is turned on. If the fluctuation is too large, then investigate these three points. Cleaning the carbon deposits and replacing the spark plugs usually solves the problem.
