Using engine oil with excessively high viscosity can indeed lead to a decrease in a car's power performance, specifically manifesting as delayed acceleration and reduced power output. Especially during the cold start phase, high-viscosity oil cannot quickly reach the lubrication points, causing the crankshaft rotation resistance to increase by approximately 15%-20%, which directly affects the throttle response speed. For turbocharged models, although high-viscosity oil (such as SAE 20W-50) can maintain oil film strength under high-temperature operating conditions, it will cause an increase in the hydraulic resistance of the turbo bearing, making the turbo lag phenomenon more obvious. Older engines, due to increased component wear gaps, actually require higher viscosity oil (such as SAE 10W-40) to maintain sealing, while new cars need to use the factory-specified viscosity (mostly SAE 5W-30) to achieve the optimal balance between power and fuel economy. It is recommended that car owners strictly follow the oil viscosity standards specified in the vehicle manual, change the oil regularly every 5,000 to 10,000 kilometres, and prioritize synthetic oil products certified by API SN/SP or ACEA C3.
