Does Thicker Engine Oil Affect Cold Starts?
2 Answers
Thicker engine oil does affect cold starts. When the oil is too viscous, it increases resistance during startup, making it harder for the engine to start and accelerating component wear. Different grades of engine oil have distinct characteristics, with varying performance in low-temperature startup capability and high-temperature anti-wear/adhesion properties. The viscosity of engine oil is inversely proportional to temperature. When the engine is cold, the oil viscosity is higher. If excessively thick oil is used, it places additional strain on the starter motor and battery. When selecting engine oil, consider the vehicle's operating temperature environment and purchase oil according to the grade and viscosity specified in the owner's manual. Carefully check the grade and viscosity markings on the product packaging, ensuring the oil meets or exceeds the minimum required specifications.
Having driven for over a decade, I've experienced how thickened engine oil can indeed affect cold starts. Especially in winter, starting the car feels particularly strenuous, with the engine coughing for quite a while before firing up. The main reason is that overly viscous oil has poor fluidity. During cold starts, oil needs to quickly circulate to lubricate all engine components—thick oil moves slower, increasing friction between parts and accelerating wear. Prolonged use can raise fuel consumption and even damage internal engine components. It's advisable to use lower-viscosity oil in cold seasons, such as 5W-30 or 0W-20 grades, to improve startup smoothness and engine longevity. I used to be unaware and chose the wrong oil, resulting in sluggish starts. Now I've learned my lesson—I always select seasonally appropriate oil during changes. Additionally, older vehicles require extra attention; timely maintenance prevents major repairs, as the engine is the core component after all.
