Updated July 9, 2023

The Essential Guide – What Kind Of Oil Does A Generator Use?

A generator can save your life during power outages. Maintenance is essential to keep your generator running smoothly whether you use it for backup power or for different purposes.

Selecting the proper oil for your generator is an important part of maintenance. We’ll walk you through the crucial factors to consider so that you can choose the right option in this detailed guide.

What Kind Of Oil Does a Generator Use

So, What Kind Of Oil Does a Generator Use?

Generators typically use engine oil, which is specifically formulated for the lubrication and cooling of internal combustion engines. The type of oil required for a generator depends on the specific model and the type of engine it has.

It’s important to refer to the generator’s user manual or consult the manufacturer’s recommendations to determine the correct type and viscosity of oil to use.

Commonly Recommended Types of Oil For Generators.

  • 20W-50  Personal recommendation for a portable generator 
  • SAE 10W-30
  • SAE 10W-40
  • SAE 15W-40

However, always defer to the manufacturer’s guidelines for your particular generator model.

Two Primary Types Of Oil Used in Generators

Engine Oil: Smaller portable generators that use an internal combustion engine, such as gasoline or diesel engines, require engine oil similar to what is used in automobiles.

These generators often use multi-viscosity oils, such as SAE 10W-40 or 20W-50, which provide good lubrication in a wide range of temperatures.

Lubricating Oil: Larger industrial generators, typically powered by diesel engines, use specific lubricating oil.

These oils are designed to withstand the high temperatures and pressures generated by the engine and provide effective lubrication and cooling.

The oil used in these generators often complies with specific industry standards, such as API (American Petroleum Institute) specifications.

It is crucial to consult the generator’s user manual or manufacturer’s recommendations for the exact type and viscosity of oil to use.

Related: Why Is There Oil In My Generator Air Filter?

Understanding Generator Oil Requirements

it’s essential to understand the oil requirements of your generator to ensure its optimal performance and longevity. Generators rely on proper lubrication to keep their internal components running smoothly.

Manufacturer Recommendations

The user manual provided by the generator manufacturer is your primary source of information regarding oil requirements. It contains specific guidelines and recommendations tailored to your generator model. Pay close attention to the oil type, viscosity, and any additional instructions provided by the manufacturer.

Oil Viscosity

Viscosity refers to the oil’s resistance to flow at different temperatures. It’s denoted by a numerical value followed by a (10W-30). The W stands for winter, indicating the performance of the oil in colder temperatures.

A lower first number (e.g. 5W) signifies better cold start performance while a higher second number (e.g. 40) represents improved high-temperature stability. Follow the manufacturer’s specifications to select the appropriate viscosity for your generator.

Climate Considerations

Consider the climate in which your generator operates. Cold weather can make startup challenging, requiring oil with better low-temperature performance.

In colder regions, oils with lower viscosities such as 5W-30, are often recommended. Conversely, in hot climates, higher viscosity oils, such as 20W-50, may be required to maintain proper lubrication and prevent engine damage in high-temperature conditions.

Oil Additives

Some generator manufacturers recommend oils with specific additives to enhance engine protection and performance. These additives may include detergents dispersants anti-wear agents, corrosion inhibitors, and antioxidants.

They help keep the engine clean, prevent sludge buildup, and protect against wear and corrosion. Check the user manual or manufacturer recommendations to determine if specific additives are required or recommended for your generator.

Synthetic Oil

Synthetic oils offer advanced lubrication properties and improved performance compared to conventional oils. They provide better protection against high temperatures reduce friction, and can extend the oil change intervals.

However, not all generators are compatible with synthetic oils so it’s crucial to consult the user manual or manufacturer guidelines to determine if they are recommended or approved.

Oil Change Intervals

Regular oil changes are vital for maintaining optimal generator performance. The user manual will specify the recommended oil change intervals based on factors like operating hours or time duration.

Adhering to these intervals ensures that the oil retains its lubricating properties and helps extend the life of your generator.

Related: What Type Of Oil 2100 Power Stroke Generator?

Types of Generator Engines and Oil Requirements

There are various types of generator engines, each with its own specific requirements for oil. Here are a few common types of generator engines and their oil requirements.

Gasoline Engines: Small portable generators often use gasoline engines. These engines usually require a 4-stroke motor oil with a viscosity grade of 10W-30 or 10W-40. It’s important to check the manufacturer’s recommendations to determine the exact oil specifications for your specific gasoline generator engine.

Diesel Engines: Larger standby generators and industrial generators often use diesel engines. Diesel engines typically require diesel-rated oil with a higher viscosity. Common viscosity grades for diesel engines include 15W-40, 10W-30, or 5W-40. Again, it’s crucial to consult the manufacturer’s guidelines for precise oil requirements.

Natural Gas and Liquid Propane Engines: Some generators are powered by natural gas or liquid propane. These engines often have specific oil requirements which may differ from gasoline or diesel engines. It’s essential to consult the generator manufacturer’s documentation or user manual to determine the recommended oil type and viscosity for natural gas or LP engines.

Bi-Fuel Engines: Bi-fuel generators can run on multiple fuels such as diesel and natural gas. The oil requirements for these engines may depend on the primary fuel source. Check the manufacturer’s specifications for the recommended oil type and viscosity for bi-fuel engines.

It’s important to note that while these are general guidelines, specific oil requirements may vary depending on the generator manufacturer, model, and operating conditions. Always refer to the manufacturer’s documentation or user manual for accurate information on oil requirements for your specific generator engine.

Multipurpose Engine Oil

Multipurpose engine oil is a type of motor oil that can be used in both gasoline and diesel engines. It can also be used in engines that run on natural gas or propane.

This oil is designed to protect your engine from wear and tear, while also providing excellent fuel economy.

The disadvantage is that it doesn’t offer the same protection against rust as some other oils do.

Gearbox Lubricant

A gearbox lubricant is a special type of oil that helps keep your generator’s gears running smoothly. There are many different types of gearbox lubricants on the market, so it’s important to choose the right one for your particular generator.

Some oils work better in colder climates and some in warmer climates. If you don’t know which kind you need, consult with an expert. The wrong kind of oil can lead to costly repairs down the line.

Compressor Oil

Compressor oil is one of the most popular options. Compressor oil is made from petroleum and it has a variety of applications.

It can be used as a lubricant, coolant, or sealant. Compressor oil can also help clean and protect your generator from corrosion.

For instance, when you’re using an air conditioner in hot weather, a compressor that isn’t running at its best will produce less power which leads to more heat.

Your air conditioner might stop working altogether because it is unable to compensate for all this extra heat.

A solution would be to use some form of cooling agent to maintain the necessary temperature range inside your home or office.

The other option would be compressor oil which helps remove the additional heat from your machine by circulating the refrigerant throughout its system.

Cooling System Fluid

As the weather gets warmer, it’s important to make sure your generator’s cooling system fluid is up to the task.

It’s also important to have the right amount of coolant in your engine and refill it when necessary. there are a variety of fluids that can be used in different environments and climates but these three will serve you well no matter where you live SAE 20W-50 mineral oil: this fluid has excellent thermal and mechanical stability.

If used as recommended, this oil will resist oxidation even under extreme heat or cold conditions.

The viscosity of this type of oil can help protect the engine from wear during start-up or while idle periods by preventing the metal parts from scraping against each other.

SAE 20W-50 mineral oil is recommended for colder climates where some water might get into the system.

In warmer areas without such humidity concerns, SAE 10W-30 would be preferable because it has greater lubrication qualities at higher temperatures.

Conclusion: What Kind Of Oil Does a Generator Use?

Choosing the right oil for your generator is crucial for its performance and durability. Proper oil selection ensures lubrication heat dissipation and friction reduction all of which contribute to the generator’s smooth operation.

Consider factors like viscosity oil quality and manufacturer recommendations when selecting generator oil. Different types including conventional synthetic and synthetic blends offer unique benefits so choose the one that suits your generator best.

Follow the manufacturer’s oil recommendations to maintain the warranty and optimize performance. Popular brands like Honda, Generac, Briggs & Stratton, Yamaha, and Cummins provide specific oil specifications for their generators.

FAQs: What Kind Of Oil Does a Generator Use?

Can I use regular motor oil in a generator?

No, using regular motor oil is not recommended for generators.

How often should I change the oil in a generator?

Oil should be changed every 50 to 100 hours of running.

What happens if I use the wrong type of oil in my generator?

Using the wrong oil can lead to reduced performance and potential engine damage.

Can I mix different types of generator oil?

It is not recommended to mix different types of oil in a generator.

How do I dispose of used generator oil?

Dispose of used oil at authorized oil collection facilities or recycling centers.


About Saad Ahmed
Hi am Saad Ahmed and as you can see that i have been a generator mechanic for the past 12 years of experience in this industry. But now i am Full time digital marketer and affiliate blogger.