5W-20 vs. 5W-30

What's the Difference?

5W-20 and 5W-30 are both types of motor oil commonly used in vehicles. The numbers in their names refer to their viscosity, or thickness, at different temperatures. 5W-20 is thinner and flows more easily at low temperatures, making it ideal for cold weather conditions. It provides better fuel economy and is recommended for newer engines. On the other hand, 5W-30 is slightly thicker and offers better protection at higher temperatures and under heavy loads. It is often recommended for older engines or vehicles that are regularly driven in hot climates or used for towing. Ultimately, the choice between 5W-20 and 5W-30 depends on the specific requirements of the vehicle and the prevailing weather conditions.


Recommended forMost newer carsMost older cars
Temperature rangeWide rangeNarrow range
Fuel economyImprovedSlightly reduced
Engine protectionGoodExcellent
PriceUsually cheaperUsually slightly more expensive

Further Detail


When it comes to choosing the right motor oil for your vehicle, there are several factors to consider. One of the most important decisions is selecting the appropriate viscosity grade. In this article, we will compare the attributes of two popular viscosity grades: 5W-20 and 5W-30. While both oils are commonly used in modern engines, they have distinct characteristics that can impact engine performance and longevity. By understanding the differences between these two grades, you can make an informed decision about which oil is best suited for your vehicle.


Viscosity refers to the oil's resistance to flow at different temperatures. The first number in the viscosity grade represents the oil's flow characteristics at low temperatures, while the second number indicates its behavior at high temperatures. In the case of 5W-20 and 5W-30, the "5W" signifies that both oils have a similar viscosity at low temperatures, making them suitable for cold starts. However, the difference lies in their high-temperature viscosity.

5W-20 oil has a lower high-temperature viscosity compared to 5W-30. This means that at operating temperatures, 5W-20 flows more easily through the engine, reducing friction and improving fuel efficiency. The lower viscosity also allows the oil to reach critical engine components faster, providing better lubrication and reducing wear. On the other hand, 5W-30 has a slightly higher high-temperature viscosity, which can offer better protection against engine stress and heat. This makes it a preferred choice for vehicles operating in extreme conditions or those with older engines that may have looser tolerances.

Fuel Efficiency

One of the key considerations for many vehicle owners is fuel efficiency. The choice of motor oil can have a significant impact on a vehicle's fuel consumption. As mentioned earlier, 5W-20 oil has a lower high-temperature viscosity, which means it flows more easily through the engine. This improved flow reduces the energy required to pump the oil, resulting in improved fuel efficiency. Additionally, the lower viscosity of 5W-20 allows the engine to operate with less internal friction, further enhancing fuel economy.

On the other hand, 5W-30 oil, with its slightly higher high-temperature viscosity, may have a slightly negative impact on fuel efficiency compared to 5W-20. The increased resistance to flow can lead to a small decrease in fuel economy, especially in newer vehicles designed to optimize efficiency. However, the difference in fuel consumption between the two grades is generally minimal and may not be noticeable in everyday driving conditions.

Engine Protection

Another crucial aspect to consider when choosing motor oil is its ability to protect the engine from wear and damage. Both 5W-20 and 5W-30 oils provide adequate protection for most modern engines. However, the differences in viscosity can affect the level of protection offered.

5W-20 oil's lower viscosity allows it to flow more easily through the engine, reaching critical components faster. This rapid lubrication helps reduce friction and wear, ensuring the engine remains protected even during cold starts. The lower viscosity also allows the oil to maintain a stable protective film on engine parts, preventing metal-to-metal contact and reducing the risk of damage.

On the other hand, 5W-30 oil's slightly higher viscosity provides a thicker protective film, which can be beneficial for engines operating under extreme conditions. The additional viscosity helps cushion engine parts and provides enhanced protection against heat and stress. This makes 5W-30 a preferred choice for vehicles subjected to heavy loads, towing, or high-performance driving.

Temperature Range

The temperature range in which a motor oil performs optimally is an important consideration, especially for those living in regions with extreme weather conditions. Both 5W-20 and 5W-30 oils are designed to provide reliable performance across a wide temperature range.

5W-20 oil's lower viscosity at low temperatures ensures easy cold starts, even in freezing conditions. It flows quickly through the engine, reducing wear during initial startup. However, its lower high-temperature viscosity may make it less suitable for vehicles operating in extremely hot climates or under heavy loads for extended periods.

On the other hand, 5W-30 oil's slightly higher high-temperature viscosity makes it better suited for hotter climates or prolonged heavy-duty use. It provides better protection against thermal breakdown and maintains its viscosity under high operating temperatures. This makes 5W-30 a more versatile choice for vehicles that experience a wide range of temperature conditions.

Manufacturer Recommendations

It is essential to consult your vehicle's owner's manual or the manufacturer's recommendations to determine the appropriate motor oil viscosity grade for your specific vehicle. Automakers spend significant time and resources testing different oils to identify the optimal viscosity for their engines. Following the manufacturer's recommendations ensures that your engine receives the intended level of protection and performance.

While both 5W-20 and 5W-30 oils have their advantages and can be used in various vehicles, it is crucial to adhere to the manufacturer's guidelines. Some vehicles may require a specific viscosity grade due to engine design, tolerances, or performance requirements. Failing to use the recommended oil can potentially void warranties or lead to suboptimal engine performance.


Choosing the right motor oil viscosity grade is a critical decision that can impact your vehicle's performance, fuel efficiency, and engine longevity. While both 5W-20 and 5W-30 oils have their merits, they differ in terms of viscosity, fuel efficiency, engine protection, and temperature range. 5W-20 offers improved fuel efficiency, easy cold starts, and excellent lubrication, making it suitable for most modern engines. On the other hand, 5W-30 provides enhanced protection under extreme conditions, making it a preferred choice for heavy-duty applications or older engines. Ultimately, consulting your vehicle's owner's manual and following the manufacturer's recommendations will ensure you select the right oil for your specific vehicle and driving conditions.

Comparisons may contain inaccurate information about people, places, or facts. Please report any issues.