How to check the viscosity of engine oil
Oil viscosity is an important indicator of oil flow performance and directly affects the engine's lubrication effect and fuel economy. Recently, the discussion about engine oil viscosity has become a hot topic in the car maintenance field. This article will analyze in detail the meaning of engine oil viscosity, classification standards and how to choose the appropriate engine oil viscosity to help car owners better maintain their cars.
1. Basic concepts of engine oil viscosity
Engine oil viscosity is usually expressed in SAE (Society of Automotive Engineers) standards, such as "5W-30" or "10W-40". Among them:
| symbol | meaning |
|---|---|
| Number before W (such as 5W) | Low temperature fluidity, the smaller the number, the better the low temperature performance |
| The number after W (such as 30) | High temperature viscosity, the larger the number, the thicker the oil film is at high temperatures. |
For example, 5W-30 motor oil flows better than 10W-30 at low temperatures, but has the same viscosity at high temperatures.
2. Classification of engine oil viscosity
According to SAE standards, engine oil viscosity is divided into two categories: single-stage viscosity and multi-stage viscosity:
| Type | Example | Features |
|---|---|---|
| Single stage viscosity | SAE 30 | Only suitable for certain temperature ranges |
| multi-level viscosity | 5W-30 | Adapt to wider temperature range |
3. How to choose the appropriate engine oil viscosity
Consider the following factors when selecting engine oil viscosity:
| factors | Recommended viscosity |
|---|---|
| climatic conditions | Choose a low W value (such as 0W-20) in cold areas, and choose a high W value (such as 10W-40) in hot areas. |
| Engine type | It is recommended to use low viscosity engine oil (such as 5W-30) for turbocharged engines |
| vehicle age | Old cars can appropriately increase the high temperature viscosity (such as changing from 5W-30 to 5W-40) |
4. Analysis of common misunderstandings
1.Myth 1: The higher the viscosity, the better
Although high-viscosity engine oil can form a thicker oil film, it will increase engine operating resistance and lead to increased fuel consumption. The selection should be strictly based on the manufacturer's recommendations.
2.Myth 2: Fully synthetic motor oil must be of low viscosity
Although fully synthetic motor oil has excellent low-temperature performance, it is still necessary to select the appropriate viscosity grade according to the needs of the engine.
5. Recommended table of mainstream engine oil viscosity in 2023
| Vehicle type | Recommended viscosity | temperature range |
|---|---|---|
| Japanese new cars | 0W-20 | -35℃～40℃ |
| European turbocharger | 5W-30 | -30℃～50℃ |
| American SUV | 5W-40 | -25℃～50℃ |
| Old models | 10W-40 | -20℃～50℃ |
6. Practical tips for checking engine oil viscosity
1.Low temperature test:Put the engine oil in the refrigerator and observe the flow state at -20°C.
2.High temperature test:Measure the kinematic viscosity (cSt) at 100°C with a viscometer
3.Actual driving experience:Is the cold start smooth and the engine noise changes after high-speed driving?
7. Expert advice
Professor Wang, an expert from the China Society of Automotive Engineers, pointed out: "With the improvement of engine manufacturing precision, low-viscosity engine oil has become a trend. But car owners should not blindly follow the trend and be sure to refer to the vehicle manual. Regularly checking the status of the engine oil is more important than simply pursuing viscosity."
8. Summary
Properly understanding engine oil viscosity is critical to vehicle maintenance. Through the detailed analysis of this article, I hope car owners can:
1. Understand the meaning of SAE viscosity labels
2. Choose the appropriate viscosity according to actual needs
3. Avoid common usage misunderstandings
4. Establish a scientific oil change cycle
Final reminder: When you find that the engine oil has become significantly thinner or thicker, you should check the engine condition in time, as this may be a precursor to failure.
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