宝马5系凉车打火噪音大，这种现象有不少车主们遭遇过。宝马5系冷启动声音大的可能性为：启动1分钟左右声音很小，这种属于正常现象，建议先热车1-2分钟;启动一会后怠速噪音依然很大，如果发动机传来轰鸣响声，请及时维修。宝马5系冷启动噪音大，不一定就是故障。
BMW 5 Series cool car has a lot of noise when it starts fire, which has been encountered by many car owners. The possibility of BMW 5 Series cold start sound is: the sound is very small after starting for about 1 minute, which is a normal phenomenon. It is recommended to warm up the car for 1-2 minutes first; After starting for a while, the idle noise is still very loud. If there is a loud noise from the engine, please repair it in time. BMW 5 Series cold start noise, not necessarily a fault.
宝马5系打火噪音大原因分析：
Analysis on the causes of loud sparking noise of BMW 5 Series
1、如果冷启动，发动机声音偏响，一分钟后趋于安静，热启动时声音就很小，这种属于正常现象。因为停车后，发动机内的机油会自动流回油底壳。第二天冷启动的时候，机油会慢慢从油底壳回到汽缸盖附近。如果是热启动，发动机内的机油都已经到位，润滑和密封良好，声音自然会小。所以，冷启动声音会比较大，但是持续时间不会很长，多2分钟。
1. If the engine sounds slightly during cold start, it tends to be quiet after one minute, and the sound is very small during hot start, which is a normal phenomenon. Because after parking, the engine oil will automatically flow back to the oil pan. During cold start the next day, the oil will slowly return from the oil pan to near the cylinder head. If it is a hot start, the oil in the engine is in place, the lubrication and sealing are good, and the sound is naturally small. Therefore, the cold start sound will be relatively loud, but the duration will not be very long, 2 minutes more.
2、如果在冷启动时发动机声音大，而且还发出咯吱咯吱的响声，那么就检查一下机油的使用情况，如果使用的是质量较差的汽油，也会导致发动机动力下降，造成发动机内部积碳增多，发动机噪音也会增大。
2. If the engine makes a loud noise and creaks during the cold start, check the use of the engine oil. If you use poor quality gasoline, it will also lead to the decrease of engine power, the increase of carbon deposition inside the engine and the increase of engine noise.
3、如果发动机有共振的现象，也会造成发动机的噪音大。对于咯吱咯吱的响声应该是水泵皮带或发动机皮带老化后出现打滑而导致的异响，或者是水泵叶轮、水泵轴承或发电机轴承等部位缺少润滑后已经出现磨损。还有可能是发动机抖动幅度较大时，发动机机爪与支架发生摩擦所产生的，逐项检查这些，就可以找到原因。
3. If the engine has resonance phenomenon, it will also cause the engine noise. The creaking noise should be the abnormal noise caused by the sliding of the water pump belt or engine belt after aging, or the abrasion of the water pump impeller, water pump bearing or generator bearing after lack of lubrication. It may also be caused by the friction between the engine claw and the bracket when the engine jitters greatly. Check these items one by one to find out the cause.
