Can I Use 5W-30 Instead of 5W-20 Oil?

by Synthetic Oil | Last Updated: June 4, 2023

Choosing the right engine oil for your vehicle is crucial for optimal engine performance and protection. One common question is whether it’s possible to use 5W-30 oil instead of 5W-20, or vice versa. To answer that question, let’s explore the differences between these two oil viscosities, as well as what could go wrong when using the wrong oil, and offer some guidance on how to choose the correct oil type and viscosity for your vehicle.

What is the Difference Between 5W-30 and 5W-20 Oils?

Let’s take a moment to discuss what the numbers and letters in the oil type mean. The numbers in oil viscosity ratings represent the oil’s flow characteristics at different temperatures. The first number followed by a “W” denotes the oil’s viscosity at low temperatures, while the second number indicates the viscosity at operating temperature. Understanding the differences between 5W-20 and 5W-30 oils is essential for making an informed decision.

Although the two are not entirely different, there are some key differences that may make one the better choice for your car, truck, or SUV.

About 5W-20 Oil

This oil has a lower viscosity at operating temperature compared to 5W-30. It flows more easily, providing better lubrication during startup and helping to improve fuel efficiency. It is commonly recommended for newer engines designed to operate with lower-viscosity oils. The lower viscosity also helps reduce friction and wear on engine components.

About 5W-30 Oil

5W-30 may operate at the same low temperature as 5W-20, but it is a slightly more viscous oil. It provides a thicker oil film, which may offer better protection against wear under certain conditions, such as higher temperatures or heavy loads. For this reason, 5W-30 is often used in older engines or in vehicles subjected to more demanding operating conditions. The higher viscosity can help maintain proper oil pressure and provide better protection under extreme heat or stress.

Can I Use 5-20 Instead of 5W-30 or Vice Versa?

While it may be tempting to interchange oil weights, it is generally not recommended. Instead, it is best to follow the manufacturer’s guidelines and select the oil viscosity that they recommend for optimal operation of your vehicle.

In other words, if your fresh-from-the-factory Honda Accord comes with 5W-20 in the engine, you should just stick with that oil. After all, the manufacturer’s recommendations are based on extensive testing and engineering to ensure optimal performance, fuel efficiency, and engine protection. Deviating from these specifications without explicit permission in the owner’s manual may have implications for your engine’s performance and warranty.

That said, you might find that your vehicle works better with thicker or thinner oil. If that’s the case, continue. If you would like to switch from 5W-30 to 5W-20 or vice versa, consult a qualified mechanic for some advice.

What Happens If You Use 5W-30 Oil Instead of 5W-20?

Swapping out 5W-20 for 5W-30 could potentially have several negative consequences that alter your engine’s performance. It’s not the same as using 5W-20 instead of 0W-20. While you can use one oil instead of the other, it is important to know what could happen so you can make an informed decision.

Thinner Oil Film

You know that “30,” in 5W-30? The “30” denotes its viscosity at operating temperature, which is typically around 100 degrees Celsius. This oil has a higher viscosity than 5W-20 oil at this temperature. It means that 5W-30 oil is thicker and has a slower flow rate than 5W-20 oil when the engine is running. In other words, 5W-20 is thinner and therefore flows more easily during cold starts than 5W-30. This may seem like a small thing, but the importance of proper lubrication in colder weather cannot be overstated.

When an engine sits idle for a prolonged period or experiences cold weather conditions, the oil drains down from engine parts, leaving them temporarily unlubricated. Thicker oil, such as 5W-30, takes longer to reach critical engine components and create an effective oil film, potentially leading to increased friction, wear, and even engine damage.

In contrast, 5W-20 oil, with its lower viscosity at low temperatures, flows more quickly and coats engine components more rapidly during startup. This ensures that vital parts receive immediate lubrication, reducing wear and promoting smoother engine operation.

Using 5W-30 oil instead of 5W-20 oil can result in decreased lubrication during cold starts, potentially leading to increased engine wear, reduced fuel efficiency, and diminished overall performance.

As such, if your car suggests 5W-20, use it—especially in the wintertime.

Engine Stress

Engines are meticulously designed with specific tolerances and clearances to ensure optimal performance and longevity. This means that when you use 5W-30 instead of 5W-20, there could be issues. For instance, using a different oil viscosity can disrupt the intended oil flow characteristics within the engine. Engine parts, including bearings, camshafts, and pistons, rely on a precise balance of lubrication to operate smoothly. When the viscosity deviates from the manufacturer’s recommendation, it can create additional stress on these components.

Greater viscosity may even lead to higher friction levels between moving parts, thereby generating more heat. That leads to accelerated wear and tear on the engine.

Reduced fuel efficiency is another potential consequence of using the wrong oil viscosity. The increased friction caused by using 5W-30 instead of 5W-20 can result in higher energy losses within the engine. These losses translate into decreased fuel efficiency, meaning you may need to refuel more frequently and spend more money on gasoline.

Warranty Concerns

Vehicle manufacturers specify the recommended oil viscosity for their engines to ensure optimal performance, fuel efficiency, and longevity. Deviating from these recommendations without explicit approval can have implications for your vehicle’s warranty coverage. If engine damage or failure occurs as a result of using the wrong oil viscosity, it may void your warranty. Following the manufacturer’s guidelines is essential to protect your warranty coverage and ensure proper engine care.

Final Thoughts on 5W-20 vs 5W-30

While 5W-30 and 5W-20 oils have differences in their viscosities, it is generally advisable to use the oil viscosity recommended by the vehicle manufacturer. Using 5W-30 instead of 5W-20 or vice versa without explicit approval can impact engine performance, fuel efficiency, and potentially void your warranty. Always consult your vehicle’s owner’s manual and follow the manufacturer’s recommendations for the appropriate oil viscosity. By doing so, you can ensure optimal engine performance and protection.