Why is there abnormal noise when starting the car?

[HoldenMarie]

Reasons for abnormal noise when the car starts: 1. Clutch noise. 2. Transmission shaft support bearing noise. 3. Drive axle abnormal noise. 4. Differential abnormal noise. 5. Tire noise. 6. Loose parts of the vehicle causing resonance. At low speeds, the vibration frequency is low and may be close to or the same as the natural frequency of certain components, leading to resonance. The relationship between abnormal noise and temperature: 1. Noise occurs at low temperatures and reduces or disappears as the temperature rises. Possible causes include excessive clearance between the piston and cylinder wall; incorrect depth and width of the main bearing oil groove; low oil pressure leading to poor lubrication. 2. Noise occurs when the temperature rises and reduces or disappears when the temperature drops. Possible causes include pre-ignition due to overheating; incorrect orientation of the major and minor axes of the piston skirt oval; insufficient piston ovality or too small clearance between the piston and cylinder wall; piston deformation; insufficient clearance in piston rings.