Is Thinner or Thicker Engine Oil Better?
2 Answers
Neither excessively thick nor overly thin engine oil is ideal. The concentration of engine oil is related to its viscosity—higher concentration means greater viscosity, while thinner concentration indicates lower viscosity. There’s a saying in selecting engine oil: choosing the right viscosity is best. Below are the relevant details: Overly thick oil: Using engine oil that is too thick, meaning oil with excessively high viscosity, will increase engine operating resistance, raise fuel consumption, and may even cause certain wear because the high viscosity prevents rapid lubrication of the friction surfaces of engine components. Overly thin oil: Using engine oil that is too thin generally leads to louder engine noise, reduced sealing performance, and a higher likelihood of oil burning. Similarly, overly thin oil cannot form an adequate oil film, resulting in friction and wear on component surfaces.
I've been driving for over a decade and think the thickness of engine oil depends on the situation. In cold winters, thinner oil flows better, allows quicker cold starts, provides better engine protection, and reduces wear. When it's hot in summer, thicker oil can better withstand high temperatures, has better sealing properties, and prevents oil leaks. But don't switch back and forth too often. My old car's engine is a bit worn, so thicker oil seems to work better, while new cars should follow the manual's recommendation for thinner oil. If you mostly drive short distances in the city, thinner oil saves more fuel; for long highway trips or heavy loads, thicker oil is more stable. Just don't change it randomly—check your car's requirements and seasonal changes carefully to avoid oil burning and other issues.
