Engine making strange noises when starting cold but miraculously disappearing when warm could be due to four main reasons:
1：The car's alternator belt may be too tight or slipping, causing noise during startup. It is recommended that the owner seek a professional to adjust or replace the belt to ensure a smooth, noise-free start.
2：The water pump pulley or engine pulley bearings may be slightly worn, causing noise during startup. Replacing these parts will be key to solving the problem.
3：Faulty fuel pump or oil pump bearings could cause strange noises when starting cold. If this occurs, it is essential to repair or replace the damaged parts to ensure the vehicle runs properly.
Under normal circumstances, there should be no strange noises when starting a cold car. If abnormal sounds occur, it indicates a potential issue. When starting cold, the engine and parts are not at normal operating temperature, so noises are somewhat inevitable, but these sounds should disappear once the operating temperature is reached.
Additionally, in winter, cold start noises may be more noticeable. Therefore, preheating the vehicle for at least 2 minutes before driving (30 seconds in summer) can help eliminate noises and better protect the engine and other components.
