8 Best Oils for Your Generator to Protect the Engine and Prolong Its Life

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Last updatedLast updated: January 03, 2022
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Generators are an integral part of our lives, and they deserve a lot of care. The perfect generator oil will go a long way in keeping your generator engine functional and clean. High-quality oil will not only maintain the safety of your engine, but it can also extend its life.

Brands are coming out with new generator oils every day, and it can be difficult to select the best option. So, we took it on ourselves to help you. During our quest to find the best oil for generator, we reviewed 50 products on the market and then narrowed down the list to just 8 options.

For our review, we took certain important factors into consideration. The type of oil, synthetic or conventional, is an individual preference. The viscosity and optimal temperature of the oil can also affect its usability. The certification of any oil is an indicator of its safety and reliability. Read on to know more about our top picks!

Top 8 Generator Oils Review 2022

  • Type: full synthetic
  • Viscosity: SAE 5W-30
  • Temperature range: -22 to 95°F
  • Certifications: API SN PLUS / SN; ILSAC GF-5; ACEA A1/B1; GM dexos1® Gen 2; GM 4718M; GM 6094M
  • Volume: 5 quarts

When it comes to maintaining motors, you cannot go wrong if you rely on Castrol. The Castrol® EDGE® formula is impressive. A synthetic motor oil, this product is versatile when it comes to usage. You can use it for the engine in your generator in order to increase its performance without facing any issues. The Castrol EDGE is powered by Fluid TITANIUM Technology, which gives the engine tremendous protection and also boosts its performance.

If your generator has a modern and small engine, you need to provide it with oil that can meet the increased expectations. This oil is designed to keep the structure of the engine intact, even under pressure. This helps to cut down on the friction caused and allows the engine to perform well.

What are its best features?

  • Improves oil film strength
  • Uses the Fluid TITANIUM Technology
  • Increases fuel economy

What could be improved?

  • May not be compatible with all generators
  • Type: synthetic blend
  • Viscosity: SAE 15W-40
  • Temperature range: 15 to 122°F
  • Certifications: API CK-4; CJ-4; CI-4 PLUS; CI-4, CH-4; Cummins CES 20086, DDC DFS 93K222; VDS-4.5; MACK EO-S – 4.5; Caterpillar ECF-2/ECF-3; Ford WSS-M2C171-F1
  • Volume: 1 gal.

The Shell ROTELLA® T5 15w-40 is the synthetic blend that you will fall in love with. Equipped with the Triple Protection Plus technology, this engine oil will give you access to all the benefits that are characteristic of Shell ROTELLA. However, this product is a step up from their previous formulations. The Triple Protection Plus technology combines the goodness of an additive technology called the Triple Protection and the advantages of Shell PurePlus technology.

This advanced formula will check the blocking of exhaust and will also boost the engine fuel efficiency. The oil comes with synthetic base oil components that can help in improving cold starts. By reducing fuel consumption, this oil will allow you to save some money in the long run. If you use this oil, your engine will be clean and protected during long oil drain intervals.

What do we love it for?

  • Powered by unique technologies
  • Protects the engine
  • Can increase the fuel efficiency

What were we disappointed with?

  • Packaging is prone to leakage

Briggs & Stratton SAE 5W-30 Synthetic Small Engine Motor OilBest Oil for Engine Maintenance

  • Type: synthetic
  • Viscosity: SAE 5W-30
  • Temperature range: -22 to 95°F
  • Certifications: APISJ/CD
  • Volume: 32 oz.

Finding the perfect engine oil for your generator is no easy task, but one that you have to accomplish. Getting your hands on the genuine Briggs & Stratton Small Engine Motor Oil, SAE 5W-30 will make it more convenient for you to use your generator. This high-quality oil is designed to meet the needs of your power equipment and improve its performance at the same time.

If you switch to this synthetic oil, it is likely that your engine will be able to handle the wear and tear much better. It will become resistant to the pressure, and that will allow the generator to give its best performance even during severe operating conditions. The inherent strength of this formula will allow the generator to keep running for a very long time. Your engine will develop better low-temperature fluidity and more thermal stability.

What do we love it for?

  • Cuts down on the risk of equipment failure
  • Reduces maintenance costs
  • Improves the engine performance

What were we disappointed with?

  • Pricey

Honda 08207-10W30 PK2 Motor OilBest Conventional Oil

  • Type: conventional
  • Viscosity: SAE 10W-30
  • Temperature range: 0 to 86°F
  • Certifications: API SM
  • Volume: 32 oz.

If you want your generator to give you the best performance that it possibly can, then you must keep the engine well-lubricated at all times. It is important to remember that not all engine oils will not perform the same way, so you should be careful when choosing the best oil for your generator.

The Honda 32 oz. SAE 10W-30 Motor Oil is designed to protect your engine and make it efficient. You can use the oil in any 4-cycle engine in order to get the best results. This oil will allow you to maximize the use of your power equipment. The formula is unique and especially meant to fulfill the needs of different kinds of power equipment.

If you can get your hands on the original product, you will be more than satisfied. Made with a combination of expensive shear-stable polymer additives and high-quality base stocks, the oil will bring life to all 4-stroke engines. This oil is also resistant to thermal breakdowns and viscosity.

What makes it stand out?

  • Ideal for all 4-cycle engines
  • Unique blend by Honda
  • Designed for power equipment like generators

Which disadvantages must you keep in mind?

  • Expensive

AmazonBasics Full Synthetic Motor Oil, SN Plus, 10W-30Best Oil for Engine Protection

  • Type: full synthetic
  • Viscosity: SAE 10W-30
  • Temperature range: 0 to 86°F
  • Certifications: API SN and SN Plus; ILSAC GF-5
  • Volume: 5 quarts

The AmazonBasics Full Synthetic Motor Oil is stamped with Amazon’s reliability, and it is unlikely that this product will not work out for you. The oil has been formulated to allow the engine to cope with longer drain intervals.

This product is not just another synthetic blend that you can buy from the market. It will provide your engine with effective lubrication so that all the moving parts of the engine are protected at all times.

The AmazonBasics full-synthetic motor oil will give you great quality at an affordable price. API SN and ILSAC GF-5 approved, the oil will work wonders when it comes to making your generator more efficient. It can prevent build-up so that there is no rust and corrosion collecting on the engine. Moreover, the engine functions smoother.

What makes it special?

  • Perfect for longer drain intervals
  • Reduces friction
  • Offers resistance to thermal breakdowns and viscosity

What cons did we find?

  • Packaging could have been better

Generac Full Synthetic Motor Oil 5W-30 SNBest for Prolonging Engine Life

  • Type: synthetic
  • Viscosity: SAE 5W-30
  • Temperature range: -22 to 95°F
  • Certifications: API SN
  • Volume: 1 quart

Generac is a brand that is known to come with excellent formulations for your engine. Your generator deserves excellent care if it is to last for years to come. You need to choose the best oil that will protect the engine and also increase its abilities.

This Generac Full Synthetic Motor Oil is made with a high-quality synthetic base that is further fortified with the help of an advanced additive. If you switch to this oil for your generator, you might even extend the life of the engine. The formula has been designed to provide maximum protection against friction and viscosity breakdown. It will reduce the chances of an engine shutdown.

This oil will also protect the engine from sludge formation and varnish deposits. The engine remains clean, and there will be no undue clogging.

What are our favorite features?

  • Protects the engine
  • Prevents clogging
  • Formulated with high-quality raw materials

What could be better?

  • Expensive compared to other oils
  • Type: conventional
  • Viscosity: 10W-30
  • Temperature range: 0 to 86°F
  • Certifications: API SN and SN Plus; ILSAC GF-5; Chrysler MS-6395
  • Volume: 5 quarts

The Pennzoil Motor Oil will prove to be an excellent choice for your generator, and it will boost the performance of the engine from the very first oil change. Formulated using a traditional oil base, the oil is effective. It is also fortified with the help of Active Cleansing Agents that play a significant role in preventing dirt and contaminants from affecting the efficiency of your engine. Contaminants can often damage your engine and have a negative effect on its performance. The cleansing agents in the oil will keep the engine clean, and it will always be highly responsive.

The Pennzoil conventional oil also helps to eliminate the sludge left by lesser oils after you make the switch so that the engine can start afresh. It cleans the engine by lifting off the sludge deposits and dissolving them.

What makes it stand out?

  • Controls high-temperature oxidation
  • Provides extra protection to the engine
  • Continuous cleaning process

Which disadvantages must you keep in mind?

  • Product can get damaged during shipping

Briggs & Stratton 30W Engine OilBest Made in the USA

  • Type: conventional
  • Viscosity: SAE 30
  • Temperature range: 40° to 100°F
  • Certifications: API SJ/CF
  • Volume: 48 oz.

This Briggs & Stratton 30W Engine Oil has been made in the United States with the highest quality raw materials. This special warm weather formula can be used even when the temperature is between 40°F and 100°F in your area. Formulated especially for air-cooled 4-cycle small engines, this oil will be perfect for your generator since it is both effective and versatile. It can keep all kinds of outdoor power equipment engines running irrespective of high operating temperature ranges.

All the oil products made by the company undergo a series of tests and evaluations before they release them into the market, and you can be assured of their high quality. This synthetic oil does not change its performance depending on the temperature, which can prove to be a huge advantage if you live in warm regions.

What are our favorite features?

  • Unique warm weather formula
  • Perfect for air-cooled 4-cycle engines
  • Made with high-quality raw materials

What could be better?

  • Packaging is cheap for the price

Things to Consider

While we have selected a handful of generator oils that satisfied all our requirements, you have to make a final choice for yourself based on your own needs. Everyone uses their generator in their own personal manner, and so nobody will know better than you what your generator requires. We have created this buying guide in order to lend you a helping hand as you browse through the products and select your favorite.

Check the engine oil requirements of your generator carefully

8 Best Oils for Your Generator to Protect the Engine and Prolong Its LifeIf you want to make no mistakes when it comes to maintaining your generator, then you must devote a significant amount of time going through the owner’s manual that came with the machine. Buying and using generator oil before you are acquainted with the needs of your generator is not a great idea because a wrong choice can cause permanent damage to your machine. All portable generators are accompanied by a user’s guide, which you must go through in order to understand how the engine works. You will find that the manual section talks about everything related to generator maintenance, including the exact kind of oil that your engine needs.

Since there are many power generators available on the market, you have to be careful about matching your model with the kind of oil it requires. You cannot afford to lose the manual, or else you will have to contact the company again to get the required information. You should also find out what type of engine is used by your generator.

Most portable generators use four-stroke engines nowadays, but there are some models out there that still use two-stroke engines. Always remember that different types of engines require different types of oil. Do not go in with any assumptions.

Generator oil features to consider

In order to find the perfect generator oil, you have to examine the specifications of the product before making a purchase. There are certain factors that you should take into consideration in order to make a wise choice.

Type: Conventional or synthetic

8 Best Oils for Your Generator to Protect the Engine and Prolong Its LifeThe easiest way to understand the difference between traditional and synthetic oil is that the latter is a human-made version of the former. Synthetic oils are manufactured by combining a base oil and a carrier oil with powder additives. However, both synthetic and traditional oils are sourced from crude oil. The exceptions are the synthetic oils that use a different oil as the base compound.

Synthetic oil and traditional oil usually do not share the same degree of refinement. You will always find that synthetic oil is far more refined than traditional oil. As a result, it performs better in the long run. Synthetic oil cuts down on friction and reduces the amount of engine sludge that is produced. If you switch from traditional oil to synthetic oil, you will notice a significant boost in performance. However, traditional oil is usually more affordable and can get the job done effectively. If you have budgetary restrictions, you might not be comfortable investing synthetic oil over and over again.

There are different kinds of synthetic oil, as well. Full synthetic oils like the Castrol 03084 EDGE 5W-30 are absolutely pure, while synthetic blend oils like the Shell Rotella T5 are made by mixing traditional oil with technologically advanced counterparts. If you opt for a synthetic blend, you will be able to enjoy the advantage of additives at a lesser cost.

With synthetic oil, you will have to face fewer emissions and experience a better fuel economy. Moreover, it can keep the engine free of sludge and improve its performance at the same time. On the other hand, the performance boost might not be very apparent even though you are spending triple the amount of money as compared to traditional oils. The Honda 08207-10W30 PK2 Motor Oil is an excellent traditional oil to go for.

Viscosity and temperature range

The environment in which the generator is running should be taken into account because the engines have to adapt to different temperatures. There are certain oils that can only perform well in extreme temperatures. For example, the Briggs & Stratton 30W Engine Oil is ideal for warm temperatures. On the other hand, you can also get your hands on a generator oil that can perform in a wide range of temperatures. The Briggs & Stratton SAE 5W-30 is a versatile choice. The manufacturer’s guide will tell you the ideal operating temperature range for a particular oil.

Viscosity refers to the oil’s resistance to flow, and it is included in the name of the oil. The first number placed before “W” indicates the viscosity at 0 degrees Fahrenheit, and the second number indicates the value at 212F. The higher the second number, the thicker the oil is.


The certification that accompanies a generator oil will tell you a lot about its effectiveness and reliability. When it comes to generator oil, it is usually recommended that you should go for products from established brands as they tend to be more refined. The generator oil is made to undergo a series of tests and awarded certification by various organizations to indicate its qualities.

  • Make sure that you check the engine oil level freq8netly so that the engine is never left without sufficient lubrication.
  • The appearance of the oil gives away significant information. If the oil has turned black, it should be replaced immediately because it has high carbon content.
  • If you want to check whether the oil is functional, check how it smells. Oil that has gone bad will have a different smell.
  • The maintenance interval will differ based on your usage and the requirements of your generator. Most generators come with fuel monitors nowadays, so keep an eye out.
  • Ensure that you are using the proper grade of oil if you want your engine to perform well and last longer.


Conventional oils are something we all know about, and synthetic oil is a man-made version of oil. In order to make synthetic oil, one would need a base oil, a carrier oil, and powder additives. Both of them are made from highly refined crude oil. The main difference between traditional oil and synthetic oil is their level of refinement. Synthetic oils are usually much more refined than traditional oils, which can prove to be an advantage for your machine. Moreover, they are better when it comes to improving performance. Not only can they protect the engine, but they can also keep it clean. Synthetic oils can easily adjust to different temperatures. However, traditional oil is significantly cheaper than synthetic oil. If budget is a concern for you, then you might not want to switch synthetic oil. The final choice depends on what you are looking for. If you are not willing to shell out the extra money for the advantages, then traditional oil will get the job done for you. You can also switch between the two without any problems.

There is no compulsion as such that you must switch the generator oil between summer and winter unless you experience extreme temperatures. While the concept in itself is not wrong, you can simply avoid the hassle if you opt for a generator oil that can work under different temperature conditions. There are many generator oils on the market that can adapt to a wide range of temperatures. However, you can also buy an oil that caters to extreme temperatures. Very cold temperatures are ideal for lower-viscosity oils, and very hot temperatures are perfect for higher-viscosity oils.

Our Verdict

All the generator oils that we mentioned above are capable of getting the job done for you, but we should mention our favorites.

The Castrol 03084 EDGE 5W-30 Motor Oil, with its Fluid TITANIUM Technology, is meant to improve the performance of your engine to meet your requirements while giving it adequate protection. Moreover, it can also decrease the fuel consumption of the generator so that you save some money.

The Shell Rotella T5 Synthetic Blend comes with the Triple Protection Plus technology, which means that your engine will remain sturdy and clean at all times. It will reduce the number of cold starts and also cut down on the consumption of fuel.

The Briggs & Stratton SAE 5W-30 is designed to improve the resistance of your engine. If you use this oil, your engine will perform impressively even in bad operating conditions.

What will be your pick for the best oil for your generator?

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