Excessively high engine oil viscosity can lead to various abnormal symptoms in the engine, mainly manifesting as difficulty in cold starting, reduced power performance, and decreased efficiency of the lubrication system. In low-temperature environments, high-viscosity oil has poor fluidity, causing delays in oil pumping, increased rotational resistance of the crankshaft, and thus higher load on the starter motor or even startup failure. During operation, viscous oil increases the frictional resistance of moving parts such as piston rings and cylinder walls, which not only reduces engine output power but also increases fuel consumption by approximately 5%-10%. Meanwhile, the circulation rate of high-viscosity oil slows down, and its cleaning capacity decreases by about 30%, failing to effectively remove metal debris and carbon deposits, which may cause oil passage blockages. In addition, the reduced heat dissipation efficiency raises the engine operating temperature by 10-15℃, and prolonged operation may accelerate the aging of rubber seals. It is recommended to regularly check the oil condition and strictly select oil according to the SAE viscosity grade specified in the vehicle manual (such as 5W-30 or 10W-40). In tropical climate regions, products with slightly higher high-temperature viscosity can be chosen as appropriate, but exceeding the manufacturer's recommended value should be avoided.
