What causes the whistling sound during engine idle?
1 Answers
It is usually the sound from the valves or fuel injectors. The carbon canister solenoid valve can also produce this sound, but it tends to be more crisp. Additional relevant information is as follows: 1. Identification method: During idle, slightly press the accelerator to see if the frequency changes. If the frequency remains unchanged, it is likely the sound from the solenoid valve. If the frequency changes, it should be noise from the valves. If the sound is not very clear inside the car, it is generally not a big issue. Vehicles typically produce corresponding ticking sounds—one from the fuel injectors working, another from the valve area, and a similar sound from the timing chain, which is different from the ticking sound and more like a rattling noise. 2. Troubleshooting method: Generally, when a car is cold-started, the engine sound will be slightly louder than when the engine is warm. As long as the sound is even and smooth, not harsh, it is usually not a problem. This is because, when the engine is cold, the gap between the cylinder wall and the piston has not yet reached the optimal size, and the lubrication from the engine oil is not fully effective. Normally, when the engine block temperature reaches around 95 degrees, the sound will return to normal.
