Best Oil for Portable Generator 2021

Portable generators are not simple engines. The engine is the heart of the generator, and the oil is its blood.

How do you determine the best oil for portable generators?

We’ll find out shortly.

Choosing an appropriate oil is one of the most important steps in maintaining and repairing any internal combustion engine, including those found on generators. The wrong oil can cause damage or even destroy your engine.

The market is quite extensive, and there are different categories of oil. each designed specifically for certain applications or needs.

Choosing the right oil for your generator isn’t as easy as just picking one off the shelf at the local store. Perhaps you’re not sure of the difference between conventional oil and synthetic oil?

Also, you should consider your type of engine before deciding on which oil for a portable generator would best suit your needs. The most common types of engines used in generators are diesel, gasoline, or natural gas. Each has its unique characteristics that will affect how it needs to be treated when using an oil.

There might be some specific recommendations made based on the model of the engine. For instance, if you own a Honda engine, make sure you get Honda oil.

In this review article about the best oil for a portable generator, we offer you a resource to learn from and compare different options.

What Does Oil Do for a Generator?

Oil lubricates moving parts inside your generator, so they don’t wear out prematurely. It also protects against corrosion and keeps dirt away from critical areas like bearings.

A high-quality oil also helps keep air and moisture away from the generator’s engine, which can cause it to overheat and potentially break down. If you use your generator regularly, then changing the oil will help extend its life.

Best Oil For Portable Generators

Generac Full Synthetic Motor Oil 5W-30 SN

Generac Power Systems is at the forefront of generator technology. This Generac oil is full synthetic oil gaining popularity among users of high-temperature motors in general, particularly generators.

Traditional motor oil, refined from crude oil, changes over time and becomes thicker due to heat.

Of course, this naturally poses massive problems for lubricating engine oil. Traditional motor oil is a thicker oil that can’t move in the engine as intended, and the engine stalls. If this has happened to you before, you’ll cherish the value of synthetic engine oil. This oil is fully synthetic and of great importance.

Honda 08207 10W30 Motor Oil

Best for heavy-duty construction machinery, Honda is another company known for its quality products with all mechanical parts. Their engine oils is no exception because it has been shown to make engines run quieter and longer, especially with Honda generators.

This Honda generator oil is also classified as SJ by the American Petroleum Institute (API). This means that any 4-stroke engine manufactured after 1996 should be compatible with this oil.

The viscosity rating means that this can be considered the best oil for a portable generator from equatorial to the temperate environment but not as recommended for cold weather.

The price of synthetic oil always scares some people, but for the entrepreneur who relies on his generator every day or operates a portable welding machine, light towers, or other small motor-driven equipment.

It’s also a good choice for homeowners who choose Oil for standby generators in warmer environments. This Oil does a remarkable job of repelling paint deposits while maintaining viscosity throughout the year.

Cummins 3265336 Onan SAE 15W-40 Oil 

The Cummins portable generators are highly respected all over the industry, and their Onan brand is one of the reasons for the reputation they enjoy. This gallon of Onan SAE 15W-40 engine oil has all you can expect from such industry leaders.

This oil has been tested in their factories to make their motor work as efficiently as possible.

It’s a fully synthetic motor oil designed for diesel engines and works perfectly in gas-powered generators. It is formulated to resist viscosity caused by very hot engines by increasing the efficiency of engines.

Briggs & Stratton SAE 5W-30 Synthetic Motor Oil 

This Briggs and Stratton full synthetic motor oil is designed for use in small four-stroke engines like some generators.

It overcomes the viscosity problem of conventional engine oils. It is also a detergent oil that keeps the functioning parts of your engine trouble-free. This is essential for fuel efficiency and longer engine life.

The full synthetic motor oil is also known to start working as soon as you light it. Again, as its molecular structure doesn’t need to be heated to lubricate properly, you can trust this high-quality oil during cold weather.

Castrol 03057 GTX MAGNATEC 5W-30 Full Synthetic Motor Oil

In the first 20 minutes, 75% of engine wear occurs. This is the time it takes an engine oil to reach its optimal operating temperature, unlike other engine oils that drain completely into the sump when the engine is switched off.

Castrol GTX MAGNATEC is one of the best oil for portable generators with smart molecules that adhere to critical engine parts and offers an additional protective layer. Immediate protection from the first moment.

This drastically reduces engine wear and makes critical engine components up to four times smoother.

Importance of Oil to a Generator

Before you begin your search for different oils and figure out which oil is best for your generator, you first need to know how the oil affects your generator. Portable gasoline generators use engines that need oil to run properly.

These engines utilize oil to lubricate their rotating assembly in the engine’s interior to ensure that the moving metal parts have a smooth, less resistant path.

This extends the life of your engine by reducing the engine’s wear for years to come. However, over time and in many applications, this oil may begin to degrade and become less effective.

This can make your engine components more vulnerable to wear and tear. But, according to the manufacturer, adherence to the maintenance schedule for an engine oil change can largely prevent undesirable engine damage.

Related: Generator to run a furnace.

How to Select the Perfect Oil for your Generator

When buying Oil for your portable generator, there are a few important considerations to consider. To get a better idea of what type of oil you need exactly, follow these steps.

  • Read the Manual

First, check the user’s guide supplied with the set before buying oil for your portable generator. The manual part of such a guide on how to maintain the generator should mention the type of oil your generator engine requires exactly.

  • Determine the engine type

Different engine types require different oil types. Luckily, the vast majority of generators come with 4-stroke engines, which make a choice easier. But, unfortunately, there aren’t a lot of generators with 2-stroke engines.

The oil most commonly used in 4-stroke engines in generators, lawnmowers, and other related equipment is SAE 30. But you can also choose its synthetic variations, such as SAE 5W-30 and SAE 10W-30.

Read also: Best Dual Fuel Generators and Best Tri Fuel Generators

  • Check the Viscosity

Viscosity is precisely a property of the oil that determines how well the respective type of Oil is suitable for cold weather. It represents the flow resistance of the fuel. You can find out the viscosity simply by looking at the name of the oil.

  • Hold on to reputable brands.

Ensure you only purchase oil that trustworthy companies have produced. And the oil must have been approved by the Society of Automotive Engineers (SAE).

Some of the most prestigious names are Briggs & Stratton, Shell, and Generac. Check the list above to make sure you are buying quality oil with good ratings.

Related: What can a 4000-watt generator run?

Frequently Asked Questions

Can I Utilize A Different Oil Brand From My Generator Engine?

There are a few things to keep in mind when it comes to blending oil brands with separate engine brands.

First, you need to check if your generator needs a specific oil brand or weight. If only the weight is given, you can most likely get along with any top-quality branded oil in the viscosity you need.

If your generator needs a certain oil, you have to make sure that you follow the manufacturer’s recommendations. If in doubt, call the generator manufacturer or contact their customer care for inquiries.

How Often Should I Change My Generator’s Oil?

Changing the oil of your generator is one of the essential maintenance tasks you should do to ensure that your generator lasts for a long time. Refer to your generator manual to get the right maintenance schedule regarding the intervals for an oil change.

On average, you can decide to change the oil every 50 hours of use. Many generators have a runtime indicator, but for those who don’t, you’ll need to keep an eye on the number of hours you use.


Finally, thanks for reading thus far. The best oil for generators depends on several factors and we tried to include all the best oils ideal for your generator to keep working in tip-top condition for a long time. The FAQs would also help you know how often you need to change the oil and the most fitting oil for your generator brand.