5 Best Oils for Generators 2022 – Reviews & Complete Buying Guide

Finally, you have decided to buy the best oil for generators. If you are sincere about your generator, you have to gather all knowledge about the maximum protection for the engine. Everyone asks to know how to choose the best oil for the generator. That’s why we are here to give you the proper guideline choosing the perfect synthetic oil for the generator.

There are so many brands of synthetic oil available in the market for a generator. Among them choosing the best one is a difficult job but don’t worry. Our research team makes a difficult job easy for you. In this article, we’re reviewing the best oil for generators.

There are different types and numerous key factors that helped aid our compilation. If you are in a hurry, just go through the comparison table and make the buying decision quickly. Bear in mind that you also need to consider every buying factors if you want to make the best buying decision.

Reviews of Top 5 Best Oil for Generators

We have done everything necessary to ensure that this article provides all the key elements you need to know before buying the best oil for the generator.

Therefore, we are pretty confident that with the help of our comparison table, detailed reviews of the best products, complete buying guide, and FAQ section, you will be able to choose the top genuine product according to your need as long as you adhere to the tips provided here.

Name and Features Image Rating Price
1. Rotella Motor Oil This oil is a great all-rounder, best oil for portable generator. Overall Best Pick
2. Mobil 1 Synthetic Motor Oil This is a complete and popular oil with excellent overall lubrication. Overall Professionals Pick
3. Castrol Synthetic Motor Oil High-quality and maximum utility with a cheap price. Overall Budget Pick
4. Pennzoil Platinum Motor Oil Outstanding efficiency and best oil for honda Generator. Best Value for money
5. AmazonBasics Motor Oil Make your generator engine strong with a cheap price oil. Overall Luxury Pick

1. Shell Rotella T6 Synthetic Diesel Motor Oil – Best Oil for Portable Generators

  • Brand: Shell Rotella
  • Model: T6
  • Size: 1 Gallon
  • Viscosity: 5w-40
  • Liquid Volume: 128 fluid ounces
  • Characteristics: Synthetic
  • Item Weight: 23.5 Pounds
  • Warranty: Manufacturer’s warranty
  • Price: $$

OVERALL RATING: 9.9 out of 10

In our genuine product review, we have picked Rotella T6 synthetic diesel motor oil at the top position for its best value of customer review. If you are careful and sincere about your new generator, it will be your right choice. Because this product is very effective for being safe your generator.

This is one of the best oil for a portable generator. Because it will provide improved fuel economy performance more efficiently for your portable generator. Furthermore, it is great for excellent equipment protection and long engine life.

What We Like:

  • Provides equipment protection and long engine life
  • Best oil for portable generator
  • Resist viscosity loss
  • Maximum efficiency
  • Fully synthetic motor oil
  • Increases engine durability

What We Don't Like:

  • Limited warranty

Additionally, this is highly recommended for all kinds of portable generators. Besides that, it has improved heat resistance to provide maximum efficiency. For the reason that people use this oil rapidly.

Furthermore, it is best for helping maintain vehicle emission compliance. You can buy this oil for your portable generator obviously. More especially you will be able to get a manufacturer warranty for a limited time. You can pick it up now.

2. Mobil 1 120758 Advanced Full Synthetic Motor Oil – Best Oil for Gas Generator

  • Brand: Mobil 1
  • Model: T6
  • Size: 5 Quart
  • Viscosity: 0w-20
  • Liquid Volume: 128 fluid ounces
  • Characteristics: Synthetic
  • Item Weight: 23.5 Pounds
  • Warranty: Manufacturer’s warranty
  • Price: $$

OVERALL RATING: 9.6 out of 10

In the second position, we have picked Mobil 1 120758 advanced full synthetic motor oil for many more benefits. The low viscosity and the advanced full synthetic formula will help increase engine efficiency.

Furthermore, it will improve fuel economy up to 2 percent every time. Besides that, it has outstanding thermal and oxidation stability for your generator. That can help to reduce oil aging. For the reason that it is resulting in long-lasting protection of the motor. It is one of the best oil for gas generators today.

What We Like:

  • Excellent overall lubrication
  • Advanced full synthetic formula
  • Low viscosity
  • Great thermal and oxidation stability
  • Low-temperature capabilities
  • Quick start in cold weather
  • Affordable price

What We Don't Like:

  • Only for gas generator
  • Limited warranty only

The Mobil 1 provides excellent overall lubrication that is great for the gas generators. This comes with the advanced synthetic formula to gear up your generator. So you will get maximum efficiency of your generator.

Basically, it has great thermal and oxidation stability. And it is one of the famous brands of oil you know. Actually, all the savings are depending on your generator. It will provide you maximum if you have a great generator.

3. Castrol 03101 EDGE Advanced Full Synthetic Motor Oil – Best Oil for Generac Generator

  • Brand: Castrol
  • Model: 03101
  • Size: 5 Quart
  • Viscosity: 0w-40
  • Liquid Volume: 160 fluid Ounces
  • Characteristics: Synthetic
  • Item Weight: 9 Pounds
  • Warranty: Manufacturer’s warranty
  • Price: $

OVERALL RATING: 9.4 out of 10

Castrol advanced full synthetic motor oil offers over strength under a huge amount of pressure. The manufacturer named it the titanium strong for the maximum engine performance.

If you are using the generic generator it will be the best oil for you. Because we have experimented with this with a different type of generator. You need to know that Castrol recommends the bosch oil filters every time. For the maximum utility of your generator depends on Castrol.

What We Like:

  • Advanced premium full synthetic oil
  • Titanium strong for engine
  • Maximize engine response
  • Best oil for Generac generator
  • Very cheap price

What We Don't Like:

  • Best for Generac generator
  • No warranty available

Furthermore, the Castrol EDGE is engineered with fluid titanium technology. That's why it can provide the superior efficiency of any type of engine.

As a result, it will be increased the demand for performance and fuel economy of your generator. We recommend you to use this oil only for the Generac generator. Because it will maximize your engine performance truly.

4. Pennzoil Platinum Full Synthetic Motor Oil – Best oil for Honda Generator

  • Brand: Pennzoil
  • Model: Pennzoil
  • Size: 5 Quart
  • Viscosity: 5w-20
  • Liquid Volume: 160 fluid ounces
  • Characteristics: Synthetic
  • Item Weight: 10.4 Pounds
  • Warranty: Manufacturer’s warranty
  • Price: $

OVERALL RATING: 9.3 out of 10

In the number four position, we have selected the Pennzoil Platinum full synthetic motor oil for its outstanding efficiency. We think Pennzoil full synthetic SAE 5W-20 generator oil is engineered highly. It is from the revolutionary PurePlus gas to liquid technology of the manufacturer.

The authentic base oil is approximately 99.5% pure. Additionally, this oil meets vehicle warranty requirements. This synthetic generator oil provides complete engine protection as well.

What We Like:

  • Better fuel economy
  • Protects horsepower efficiently
  • Provides best wear protection
  • Quick start in cold weather
  • Nice temperature performance
  • 95.5% pure base oil

What We Don't Like:

  • Best oil for Honda generators only
  • No warranty available

This outstanding synthetic generator oil is best for the Honda generator. If you have the great Honda generator in your home or workshop, you can use this oil always.

It has excellent temperature control for every kind of machine. In the cold weather, you will get a quick start of your generator. This is perfect for all modern engines as well.

5. AmazonBasics High Mileage Motor Oil  – Synthetic Oil for Generator

  • Brand: AmazonBasics
  • Model: AM0H133Q
  • Size: 5 Quart
  • Viscosity: 10W-30
  • Liquid Volume: 160 Fluid Ounces
  • Characteristics: Synthetic
  • Item Weight: 9.35 Pounds
  • Warranty: Manufacturer’s warranty
  • Price: $

OVERALL RATING: 9.1 out of 10

In the last and final positions, we have selected a great synthetic oil for the generator. And you will be glad to know that it is also a very excellent generator oil. Though we review it in the last position it has the best quality of engine efficiency. We are talking about AmazonBasics high mileage motor oil.

First of all, this meets worldwide quality standards. this synthetic oil for the generator is heavy-duty as well. And it will make your engine long-lasting. Additionally, this is a high resistance to viscosity and thermal breakdown. That is better for your new generator.

What We Like:

  • High resistance to viscosity
  • Make your engine long-lasting
  • Heavy-duty lubricant for the generator
  • Best synthetic oil for the generator
  • Meets worldwide quality
  • Versatile and maximum efficiency

What We Don't Like:

  • No warranty applicable
  • Hefty iceberg banging around the container

Now you need to know the top benefits of this high rated generator oil. For your generator, it will provide longer drain intervals. You need to follow vehicle manual recommendations for the perfect efficiency of your machine.

This will help to minimize friction of the generator motor. For the reason that you must get enhance fuel economy. That's what you are looking for we know. So, have this outstanding oil for your loving generator.

Buying Guide

Choosing the best oil for generators is one of the hard decisions you need to make if you have no experience in using the lubricants. It can take a lot of time to get the experience and then find out the best oil for your generator. We are the experienced one here and do the work for you. We have reviewed almost every famous brand of generator oils and find out the best one. So, let’s dive in…

Necessary Tips to Buy Best Oil for Generators

In the beginning, you need to know about the features of the best generator oil. Buying the right generator oil is very important for engine health. From the research, we gather some extra knowledge about the generator. Most of the famous generator manufacturers supply their own company oil for their generator. These oils work well with their generator.

However, you have to know some quick tips before buying the exact oil for your generator. Do you know the exact requirement you need with generator oil? Sometimes you need to observe some specifications before selecting a product very carefully.

That's the reason we are here. We have already researched about top generator oils. While selecting those products we have followed some criteria to select the best oils for the generators.

Use the User manual of the Generator

First of all, it is best for you to check out the user manual of your generator. Because the manufacturers provide the right direction of using the exact oil for that generator. You can gather more pieces of information through the instruction guide easily. So, don't throw it to the dustbin. After buying your new generator you must read the user manual at a glance. Here you will find the best oil for your generator easily.

Features of Oil

What has to do after buying a generator? You must think about the oil at first. There are different oil companies available for the fuel of your generator. Every company features its lubricants according to different engines and machines. So, for the generator, you will get a different feature of oil.

We have researched that every generator needs an SAE 10W-30. The Society of Automotive Engineers grades different oil according to its features. We have consumed some other grade for the generators and they are 5w-20, 0w-20, and 5w-40. You have to choose between them. These are mostly synthetic and reliable for any kind of generator.

Here 5W means how fast your engine can start-up in the winter season or cold area. And the other code means the heat resistance capacity of your engine with this oil. So you can judge your generator engine with the SAE code very easily.

Types of Engine

There is another important thing you have to consider before buying the generator oil. You should know the type of your generator engine first. From authentic research, we have gathered a piece of valuable information. We have gotten that, the majority number of generators build in a 4-stroke engine.

And a small number of the generator are built in a 2-stroke engine. Most importantly, these engines are needed different types of generator oil. So you have to know the accurate information about your generator. Generally, we know that the 4-stroke engines are used fuel and oil separately.

On the other hand, the 2-stroke engines use a mixed solution of oil as the fuel. That's very important for every generator owner.

If you are a hobbyist or beginner, please read our full buying guide carefully. We have provided an authentic buying guide to choose the best oil for generators.

Operating Temperature

According to the user manual, we have known that the operating temperature of the environment is very important for the engine and oil. For the heavy-duty generator, it is very important to choose the perfect oil. According to the temperature you have to maintain the SAE grade.

From the SAE grade, the 5W-30 grade oil is best for the generator. Because these types of oil can help to start the engine at a low temperature. That's very amazing for the generator users.

Select the Brand

The brand is also a great factor before buying reliable and authentic oil. because the low price oil can be harmful to your generator. For a high-quality generator, you must use the superior synthetic oil for your generator.

Sometime you will notice the irritating sound of your generator because of the low-quality brandless oil. So use a reliable brand oil to keep your generator safe. There are too many reputable brands are available for the oil. These are shown below-

  • Shell Rotella
  • Mobil 1
  • Castrol
  • Honda
  • Pennzoil
  • AmazonBasics
  • Generac etc

We can recommend you these famous brand for reliable and quality oil. If you are familiar with these brands then pick up one from our comparison table. Here we have reviewed those brands very carefully.

Longevity Tips for Engine

Longevity is a great factor for the generator engine. Because every generator becomes dull after using one year or more. Because of using general oil causes damage to the generators. The longevity totally depends on the quality of the oil. For the maximum utility, you need to oil up your generator every year.

However, you need to keep in mind to use the generator properly. Furthermore, synthetic oils are better than conventional oil. You are looking for the generator oil. Because you need to change the oil of the generator. If you have used the convenient oil before, you can use synthetic oil from now. Because today the engine longevity is controlled by the quality of oil as well.

Efficiency Tips

The professionals know that efficiency doesn't depend on the oil. The engine efficiency mainly depends on the Quality of the engine and brand. You have spent some more money to buy a great generator. Then you will get the maximum efficiency. Someone thinks that the oil is the factor for the efficiency of a diesel engine.

Their thought is wrong. The high-quality generator oil can increase efficiency by 2% maximumly. Rarely we have seen this for some extraordinary products. You have to know your generator to make it efficient.

Synthetic Oil vs. Conventional Oil

Which oil is the best for your generator? Can't realize? You should know the differences between synthetic and conventional oil. Both oils are used for the motor engine. But there are too many differences between them. We will discuss in short about synthetic oil. The more refined and distilled oil are known as synthetic oil.

As a result, these are more efficient and able to increase performance. The motor generators are suitable for this oil. It will make the generator engine long-lasting and durable. These oils are faster than conventional oils.

Weight & Size

Different brand manufactured oil in different sizes and weights. Most of them, 5-quart bottle is perfect for the generators or other small engines. These are weighed about 10 pounds.

You can find the larger package as well. Some brand sells 1 gallon, 3 gallons, 10 gallons in a compact package. Now the choice is yours. Go through our product link and choose the best according to your generator.

If you are a hobbyist or beginner, please read our full buying guide carefully. We have provided an authentic buying guide to choose the best oil for generators.


Price is a vital point to consider while choosing the cheap oil for generators. We have chosen the Shell Rotella brand not only for the quality or efficiency but also for the decent price.

If you have a low budget, you should definitely stick between the AmazonBasics and Pennzoil. As all the synthetic oil has a low price with great quality. But if you have a high budget, you can choose the Mobil 1 and Castrol. They are manufactured powered with versatile uses.


Can I use synthetic oil in my Honda generator?
Honda is the most popular brand of generators. We have faced too many questions about the Honda generator. Maximum of then tell us about the use of synthetic oil. Our answer is yes. Obviously, you can use synthetic oil for the Honda generators. For the long-lasting life, you must use synthetic oil. Because synthetic oil is not harmful to the generator.
What type of oil to use in Generac generator?
This is a common questions from the maximum Generac users. Some users use the 10W-30 grade oil for their generator. But we recommend using the 5W-30 oil for your Generac generator. Because of this oil help to quickly start the engine in cold weather.
How long can you run a generator continuously?
It is one of the common question today for the beginners. The most popular brand provides the maximum durability of the generator. As a result, you will be able to use your generator up to 8 hours at a stretch. In fact, some generator brands are designed to provide reliable energy for 3,000 or 5,000 hours in total for a lifetime.

Our Verdict

Despite being the excellent generator oils, Shell Rotella is the heavy-duty oil with high-quality protection. It has an ergonomic engine efficiency at an affordable price. Though it is perfect the portable generator, it will provide the superior utility to all 4-stroke engine.

At second place is Mobil 1, which is also outstanding and heavy-duty. It is the most professional oil for the Honda generator. Though the price is a little bit higher than the average, the consumers still love this oil because of the maximum efficiency. The operating capacity of this great oil knows no bounds.

The Castrol is our best value product with maximum engine performance. Featuring a unique efficiency and feedback of this oil has become most popular recently. If you have a low budget, you can choose between Pennzoil or AmazonBasics. Both of the generator oils are for maximum protection.

If you are still confused just go through the comparison table again and choose the best oil for generators Shoot us a comment below about any questions or opinions you have. Please let us know which oil is best according to your generator.

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