The crackling sound of Euler lightning cat may be the sound produced by some metal parts expanding when heated and contracting when cooled. Especially after parking for a long time, the oil temperature in the car is relatively low, and after starting, the oil begins to flow. When the oil temperature rises, the volume will expand and crack. It may also be that the temperature of the exhaust pipe of the vehicle is relatively high, and there will be crackling sound when cold air flows outside.
The above information is for reference only. Please consult the official after-sales service of Euler for specific reasons.