Why is there loud noise when starting a cold car?
2 Answers
The reasons for loud noise when starting a cold car: 1. Oil viscosity: When the engine is cold, the oil viscosity is higher. If the selected oil is too thick, it will add extra wear to the starter motor and battery. However, if the oil is too thin, it may not form a sufficient protective film under high-temperature operation, leading to insufficient lubrication and increased wear of components, resulting in noise; 2. Engine carbon deposits: Old oil becomes thinner with use, leading to more carbon deposits; 3. Engine resonance: Abnormal noise caused by slipping due to aging of the water pump belt or engine belt, or wear due to lack of lubrication in parts such as the water pump impeller, water pump bearings, or generator bearings.
When starting a cold car, the noise is loud. After driving for a long time, I've noticed that this is often related to the viscosity of the engine oil. In cold weather, the oil thickens, its fluidity decreases, and friction between engine components increases, naturally making the noise louder. This issue is particularly noticeable in older cars or those with significant carbon buildup. In winter, when my car starts, the engine hums loudly and takes a minute or two to warm up before it quiets down. Another reason is the increased noise from belts or water pumps due to cold contraction, so checking if the tension is appropriate is also important. Regular maintenance can alleviate this situation, such as using low-temperature oil suitable for the season. Don’t wait until the problem becomes severe to address it, as it could affect the engine's lifespan. Every time the noise is loud during a cold start, I remind myself to be patient—safety first.
