Can I Use 5W30 Instead of 10W30 in my Generator? (2023)

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From multi-grade to single-grade, mineral to synthetic, there are many types of motor oil in the market today. The availability of options can be confusing, especially if you’re a beginner.

However, using the right type of oil for your generator is important as it ensures top performance and long working life.

But, can I use 5W30 instead of 10W30 in my generator?

It’s perfectly fine to use 5w30 oil instead of 10w30 motor oil in a generator. Both 5W-30 and 10W-30 have the same viscosity at operating temperature (i.e. 30). However, a 5w30 engine oil flows better than the 10w30 oil in cold weather.

In this post, we’ll talk about the difference between the two most common types of motor oil, 5w30 vs 10w30, and talk about when to use one over the other.

Read More: Can you Use Synthetic Oil in a Generator?

Table of Contents

  • What is the Difference Between 5W30 and 10W30 Motor Oil?
    • 1. Function at Low-Temperature
    • 2. Function at High-Temperature
    • 3. Performance Temperature Range
  • Can I Use 5W30 Instead of 10W30 in my Generator?
  • When Should I Switch from 5W30 to 10W30?
  • Can I Use 10W30 Instead of 5W30 in my Generator?
  • Can I Mix 5W30 and 10W30?
  • Conclusion

What is the Difference Between 5W30 and 10W30 Motor Oil?

The main difference between 5w30 and 10w30 motor oil involves the lowest temperature they can operate in. Both 5w30 and 10w30 are multi-grade motor oil that is available in both the regular and synthetic options.

They both do a great job of lubricating your engine to improve performance and extend longevity. Both the oil variants have additives to improve viscosity while giving it two viscosity grades.

The first number before the “W” indicates the viscosity or weight of oil in cold temperatures. The letter “W” here is short for winter.

The number after the “W” indicates the thickness or weight of the motor oil in the operating temperature of the engine.

Note: A single-weight motor oil like SAE 30 doesn’t come with additives to make it work like multi-grade oil in different temperatures. You need to buy two different grade oil to run the generator in summer and winter.

Although both the 5W-30 and 10W-30 oil have similarities, they have differences that set them apart from one another. Let’s look at each.

1. Function at Low-Temperature

Engines are more prone to damage when trying to start after a cold night. As the temperature comes down, the oil in the engine thickens, making it difficult for the engine to move during a cold start.

You need to use a motor oil that is rated for winter use and has the right viscosity. Motor oil viscosity is determined by the number before the “W”. The lower the number, the better it is suited for low temperatures (0°C/32°F).

Therefore, when comparing 5w30 vs 10w30, 5w30 motor oil has a lower number before the “W”. That means the 5w30 motor oil will flow more easily during the winter compared to 10w30 oil.

However, that doesn’t mean the 10w30 oil will perform poorly when the ambient temperature is cold. Both are SAE-rated oil, but the 5w30 is designed for much lower temperatures compared to 10w30.

2. Function at High-Temperature

As the engine reaches its operating temperature (100°C/212°F), the oil inside the engine becomes thin. This can pose problems like less protection against friction, foaming of oil resulting in a rapid breakdown, etc.

You need a thicker oil that when heated stays within the recommended viscosity level. The viscosity level of a multi-grade oil at high or operating temperature is denoted by the numbers after the “W”.

Since, both the 5w30 and 10w30 are 30-weight oil, they work the same in high temperatures. However, if you’ll be running your generator in hotter climates of the south, then you can need to go for 10w40 or higher viscosity oil.

3. Performance Temperature Range

Unlike single-weight motor oil, multi-weight oil like the 5w30 and 10w30 are designed to perform in a wide range of temperatures. However, the 5w30 can operate in a wider range of temperatures compared to the 10w30 motor oil.

The 5W-30 can operate in temperatures between -30oC to 35oC. Whereas, the 10W-30 can perform in temperatures between -18oC to 30oC.

Can I Use 5W30 Instead of 10W30 in my Generator?

Yes, you can use 5w30 instead of 10w30 in your generator without any problem. They are both multi-grade oil with the same oil weight of 30 at operating temperature. However, the 5w30 oil flows better in winter compared to the 10w30 oil.

The main advantage of using multi-grade oil is, they are designed to work in a range of temperatures. Both the 5w30 and the 10w30 offer the same level of performance and protection when the generator is at high or operating temperature, as they are the same weight oil.

The main distinction between these two multi-grade oils comes from their performance in winter or cold temperatures. The 5W oil is thinner in viscosity compared to the 10W, making it ideal for winter conditions.

However, make sure to follow your generator’s users manual and use the oil the manufacturer of the generator specifies.

When Should I Switch from 5W30 to 10W30?

The main difference between 5W-30 and 10W-30 is that the 5w30 flows easily in cold weather conditions compared to 10w30. That means cold starting an engine that is using 5w30 is easier and risk-free than with 10w30.

However, as the engine reaches its operating temperature, both the oil work identically as they have the same oil weight (30).

Using the generator during the winter months calls for a lower weight oil like the 5W-30 or even lower depending on the temperature. On the other hand, if your generator will only be used during summers, then a higher weight like 10W-30 or even higher is what you need.

Make sure to follow your generator manufacturer’s recommendation when choosing the type and weight of motor oil. Using a lower viscosity oil during summer will result in increased friction in the moving parts of the engine. On the other hand, using higher-weight oil during winter means difficulty starting up, less heat transfer, and an increase in drag.

Can I Use 10W30 Instead of 5W30 in my Generator?

Yes, it is perfectly alright to use 10w30 instead of 5w30 motor oil in your generator. Both the oil type has the same weight when the generator reached the operating temperature.

However, they shouldn’t be used interchangeably during generator start-up during winters as they have different weights for cold conditions. A drop in the temperature increases the oil viscosity making engine start-up difficult in cold conditions.

Using a higher-weight oil than needed will make heat transfer inefficient while increasing the oil heat significantly. Moreover, the right oil viscosity will provide adequate engine protection and reduce oil consumption.

Always follow the manufacturer’s guidelines when choosing the oil weight to ensure peak performance and longer life of your generator.

Can I Mix 5W30 and 10W30?

Although mixing 5w30 with 10w30 will not result in any major issue when the generator is running as both the oil has a similar weight. However, mixing 5w30 with 10w30 will dilute the viscosity of the oil for cold starting the generator.

As you mix 5w30 with 10w30 it creates an imbalance in the additives that give it a certain oil viscosity at low temperatures. Therefore, you can mix the oil for use in summer, and should be avoided when the temperature drops.

Moreover, mixing synthetic oil with regular oil will also dilute the benefits offered by synthetic oil.


Both 5W30 and 10W30 motor oil has a similar viscosity when the generator reaches its operating temperature. However, the main difference between 5w30 and 10w30 comes from their viscosity at low-temperature.

A 5w30 works better at low temperature compared to a 10w30 motor oil. Therefore, if you’re going to be using your generator during the winter months, then switching between the oil grades is not advisable.

Always refer to your generator’s manufacturer’s guidelines before choosing the oil grade.

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