Can you mix 5w20 and 5w30 engine oil? Read First

Can you mix 5w20 and 5w30 engine oil

Before you know it, the summer heat will be upon us which means you’ll need to change your car’s oil. Most people don’t think about the type of engine oil and go with what their owner’s manual says.

However, if you are using a 5W-20 synthetic oil, and accidentally (or intentionally) or even considering putting 5W-30 synthetic in your car, you may ask: “Can you mix 5w20 and 5w30 engine oil?”. This article will discuss the possible consequences if this occurs.

Can you mix 5w20 and 5w30 engine oil?

Yes, you can mix 5w20 and 5w30 engine oil without damaging your engine. It won’t magically extend its lifespan either. Both oils comply with two SAE grades and can be used at a wide range of both high and low temperatures.

Can you mix 5w20 and 5w30 engine oil?

However, make sure that both viscosity is compatible with your car’s engine. We still strongly recommend following the specified oil for your car’s engine. It is also important to remember that performing your own service maintenance incorrectly, such as using the wrong engine oil may void your car’s warranty.

If you are just topping up then you can safely mix a small amount of 5w30 with 5w20. The most important thing is to keep the oil level between the minimum and maximum marks of the dipstick. You don’t want to run without oil as it ruin your engine.

Related: Can I Use 10w30 Instead of 5w30? 10w30 vs 5w30 Engine Oil

What is the meaning of code in motor oils?

The “W” in 5W30 or 5w20 stands for winter and is the oil’s flow characteristic at low temperatures. Most engine manufacturers recommend a 5W or 10W oil for cold-weather starting. A 5W oil flows better at low temperatures than a 10W oil.

Number Before

  • Implies a lower range in cold temperature. 
  • A lower number means lower viscosity/runnier.
  • Lower viscosity means oil stays liquid in cold
  • 5>10 

Number After

  • Implies thickness of oil in higher temperatures
  • A higher number is better here

Difference between 5w30 and 5w20

5 refers to the viscosity rating during winter and 20 refers to the weight in hot temperature5 refers to the viscosity rating during winter and 30 refers to the weight in hot temperature
Thinner and flows quickly with less frictionThick and flows slowly due to more friction
Breaks down quickly in hotter climates and may expose parts to wear in the long runDoes not break down quickly in hotter temperatures. It can give overall protection in the long run
Less viscousMore viscous
More preferable in winterIdeal in summer and other hotter weather conditions such as engine operating temperatures
5w20 vs 5w30 Comparison Table

Many people often ask what the difference between 5w30 and 5w20 oil is. As discussed above, the first number indicates the viscosity of the oil at cold temperatures, while the second number indicates it at high temperatures. As both these oils have a winter viscosity of ‘5W’, both 5w30 and 5w20 are great winter viscosity grade oil.

When it comes to their higher operating temperature performance, 5W30 motor oil performs slightly better than 5W-20 and is a thicker oil than its counterpart. 5W30 motor oil would be more robust and not break down very easily at a higher temperature. Thus, it will protect your engine parts better under moderate oil pressure and high-temperature settings. 5W-20 oil, being the lower viscosity oil (thinner oil) than 5W-30, might help boost your fuel economy.

The 5W-20 has a lower viscosity than the 5W-30 at high temperatures. Although it does not provide as much protection as a thicker oil such as 5W-30 does but it provides adequate lubrication for your vehicle’s engine parts. However, you should always use the motor oil recommended for your car by your engine manufacturer or mechanic.

Related: Can You Mix Fully Synthetic With Semi Synthetic Oil? 

Which is better 5w30 or 5w20?

The answer is it depends on where you live. If you normally drive in hotter and seasonal climates, 5w30 engine oil is the better choice. At 100 degrees Celsius, 5w30 is going to be slightly more viscous than the 5w20. Both 5w30 and 5w20 have the same performance in cold temperatures, but you’ll have better performance with 5w30 when you are driving in hotter temperatures.

Can I use 5w20 instead of 5w30 in hot weather or summer?

Yes. If you’re driving in hot weather, it’s best to use a 5W30 motor oil. You should not use 5W-20 if you live where there are hot summers or if you have an older car that sits outside during those months or if you drive long distances on hot days (more than 100 miles). This is because the thinner viscosity oil used in the 5W20 will flow faster in warm weather, which can cause excessive frictional heat and lead to engine wear.

Is 5W-30 better for a high mileage engine than 5W-20?

The quick answer is no. A lot of people, especially in car forums, think that 5W-30 is better for high mileage engines than 5W-20, but that’s not true. You should only run an oil weight that meets your vehicle recommendations based on your climate. If you have an engine with excessive wear a slightly higher viscosity will improve compression.

There are many factors involved in determining the ideal viscosity for your vehicle, including your climate, driving style, and vehicle manufacturer recommendations.


Understanding how engine oil viscosity grade that your car needs helps you better understand how your engine works in different scenarios. Although you may find a lot of myths and suggestions on the internet to mix oil brands or mix certain types of engine oils to improve mileage or fuel economy, still the best thing to do is to follow the manufacturer’s recommendation.

In this article, we answered the question: “Can you mix 5w20 and 5w30 engine oil?”. While it is generally safe to add or mix a few volumes to top up your oil, we still advise doing it in an emergency case only. 

In general, mixing 5w20 and 5w30 will not damage your engine. However, it is still not advisable since it may void your car’s warranty.

Elevate your car maintenance game by reading our comprehensive guide on engine oil. Learn everything from the basics of oil types, to how to properly maintain and change it. Keep your vehicle running at its best, read our guide now!

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