Is Thin or Thick Engine Oil Better?
2 Answers
Under the premise of ensuring lubrication, the thinner the viscosity, the better. The reasons are as follows: 1. Better fluidity: The engine oil is mainly located in the oil pan, which is at the very bottom of the engine. When the engine is running, it needs to pump the oil from the oil pan to various parts of the engine as quickly as possible. If the oil itself is thick, its fluidity is poor, and the pumping ability is reduced. This means it takes longer to pump the oil to all parts of the engine, resulting in less satisfactory lubrication. 2. If the oil viscosity is high, the engine needs to overcome greater resistance, which inevitably consumes more fuel to meet normal power demands, i.e., it is more fuel-consuming! Therefore, many high-end cars use thinner oil.
This is actually a question many friends have asked, and over the years of driving, I've figured out some insights. Let me start with the conclusion: whether thinner or thicker oil is better depends entirely on the situation—there's no absolute answer. I remember when I first bought my car, I cheaped out and used very thin oil in the summer, which made the engine hum loudly and even increased fuel consumption a bit. Later, when I asked at a professional shop, I learned that thicker oil in the summer heat protects the engine better. On the other hand, using overly thick oil in winter made the car shake badly during cold starts, and the startup time got longer. Now, I always stick to the recommended grade in the vehicle manual—for example, if it says 5W-30, I don’t randomly switch brands. During routine maintenance, I suggest keeping an eye on the oil's color and level. Using the wrong viscosity can accelerate engine part wear, and repairs aren’t cheap. Overall, following the manufacturer's recommendations is the way to go, and regular oil changes are key.
