Top Oils for Portable Generator on the Market

Our shopping guide gives you an in-depth look at the best oil for your generator. If you aren’t sure which oil to go for, worry not as this piece got you covered.  Other than the features and tips of the best oils, this article also enlightens you on the best and most reliable oil brands available.

Best Oils for Portable Generator – August 2021

Castrol EDGE 5W-30 Advanced Full Synthetic Motor Oil

Castrol EDGE 5W-30 Advanced Full Synthetic Motor Oil

🏆 Our Electrician's TOP Pick 🏆 Castrol® EDGE® is a full synthetic motor oil that is engineered for drivers who want only the best from their engines. Castrol EDGE with Fluid TITANIUM Technology, is the natural choice for drivers who demand maximum performance and protection from their cars. Unlock exhilarating performance with every drive.


Better Fuel Economy Shell Rotella® T6 5W-40 full synthetic provides a significantly increased level of protection against harmful engine wear when compared to previous generation API CJ-4 synthetic engine oils. Advanced low-ash formulation helps control blocking of or poisoning of exhaust after-treatment devices, helping maintain vehicle emission compliance and diesel engine fuel ...
3 Valvoline Advanced Full Synthetic SAE 5W-30 Motor Oil

Valvoline Advanced Full Synthetic SAE 5W-30 Motor Oil

Designed with innovative additive technology, it’s specially formulated to fight severe engine stress from: stop & go driving, extreme temperatures, and hauling & towing.

The Research


Look into Your Generator Users Guide

This is the first step that every buyer should take. Review the Owner’s Manual or Users Guide against the generator you have. It should be kept safe as it bears all the necessary information regarding the generator. Based on past experiences, information regarding the needed engine oil is found in the maintenance section of the manual.


 Mind These Oil Features

It is very necessary to mind the viscosity of the generator oil before making any purchase. This is the most vital point to consider. You can easily find the viscosity information from the suggested type as we’ve just noticed above.

More often than not, the SAE 10W-30 is highly recommended. This SAE is a grading system that was founded by a group called the Society of Automotive Engineers. The other part of the code refers to the viscosity of the oil at various temperatures.

10W, which is the initial code number, illustrates how possible it is to pump the oil at cold temperatures.  The letter W symbolizes winter and not weight. The second number, 30, states how well and possible it is to pump the oil when heated to temperatures of 212 degrees Fahrenheit or more. The above is an equivalent of 100 degrees Celsius.

Getting oil having the American Petroleum Institute service classifications such as SN, SM, SJ and SJ are highly desirable.

This is an indication of oil that is of good quality. Nonetheless, don’t entirely depend on my proposal; instead, ensure you confirm the right type of oil in the manual. This is because of oil variation between different generators. In case you use another type of oil other than the preferred, there is a possibility of certain engine parts wearing out prematurely.


Consider Operating Temperatures

You should also consider the environment and temperatures that your oil will operate under. Luckily, this has also been mentioned in all User Manuals so far produced. The graph below is an example that illustrates the above point well.

As evident above, a 5W-30 oil type is the most suitable for a generator being used in extremely cold areas. Such a generator only permits starting temperatures that are low. That said, you should note that this oil has an increased oil use by the generator’s engine when operating temperatures are high. It is thus advisable to check the oil level prior to any use.


Know the Type of Your Engine

Knowing the type of engine is a necessary factor before settling on the best oil for your generator. Based on prior experience, very few types of generators use a two-stroke engine. Most types of generators use the four-stroke engine.

Different types of engine oils are appropriate for different generators.

In a four-stroke engine, both the fuel and oil are used differently. In a two-stroke engine, you can either buy a pre-mixed solution or personally mix engine oil and fuel in the recommended ratios. A list of the best selling oils suitable for two-stroke engines is available at Amazon.


Go for Reliable Brands

Finally, never try to save on your generators engine oil as cheap is always expensive. You may encounter problems later after going for cheap oils price rather than buying superb-quality oil. A list of the most reliable and preferred oil brands include Honda, Shell Rotella, Onan, Generac, Motor 1, and Craftsman. These are tested and proven oil brands which are highly reliable. Their good quality is also a plus. Also, offers you the best oils in the market at a fair price. You may visit the website and learn more regarding different oils. Worth noting though is that different engine oils are ideal for different generators.

That said, let’s have a look at the best oils to go for.

Best Generator Oil – Our Top Picks

Honda SAE 10W-30 Oil

This high-quality oil is produced specifically for tools and power equipment containing four-cycle engines. It tops the list of SAE 10W-30 oil categories.

This oil has the following specifications: SAE 10W-30, Non-synthetic, and API SN. It is highly recommended because it is a well-known brand, it meets and exceeds SN API, and it lubricates quickly.

This is SN oil type as per the American Petroleum Institute classifications. This classification means that it is among the best oils available nowadays. Besides, choosing this Honda oil of high quality for your generator makes the engine function efficiently. This, in turn, reduces fuel usage and ultimately saves you money.

Most people shy away from buying this oil due to its high cost. Its cost is almost equivalent to that of full synthetic oil. It is, however, an excellent oil to go for.

Shell Rotella Oil

This oil is a well-known brand, has a low oil breakdown and exceeds the highest API class. Its specifications are API CK-4, SAE 15W-40, and a Synthetic blend.

The best type of Shell Rotella oil to go for is the Shell Rotella T5. This oil combines synthetic base oils together with advanced additives thanks to its synthetic blend as earlier stated.

This blending is very necessary for diesel engines to counter resistance in increased stress and heat when necessary. In addition, this type of oil is grouped as CK-4 as per the American Petroleum Institute.

Additional features found in this oil are that it guarantees triple protection against deposits, wear, and breakdown of oil at oxidation of high temperatures. It is thus the best-rated oil for use in diesel engines.

It is also preferred due to its relatively fair cost as compared to different 15W-40 oils.

Generac Motor Oil

Protection against deposits, exceeding the highest API class, and its creation for generators are the main benefits of using this oil. The Generac Motor Oil has the following specifications: an API SN, a synthetic blend and SAE 5W-30. This oil is suitable for generators used in quite cold climates. It has a better viscosity at low temperatures and ensures an easy generator start. Full Synthetic motor oil is the best Generac choice. It is a well-known brand for moveable generators and is available in the market. Generac also produces many other standby and portable machines. This synthetic oil is fortified with superior additive technology as its name suggests.

It is classified as oil that meets the top API SN classification. Further, this oil is good for use in gasoline generators. It provides the best protection against breakdown viscosity. Other benefits include protection from sludge formation and varnish deposits on certain engine parts.

The main disadvantage of the Generac SAE 5W-30 oil is its increased oil usage for generators operating in warm climates.

Husqvarna XP+ Oil

It has the following specs: is JASO-FD certified, has a synthetic blend, and two-stroke oil. The main benefits of this oil are a low smoke formula, low operating temperatures, and ideal for two-cycle engines.

There are a few machines that have an ancient two-cycle engine but most generators have four-stroke engines. However, the Husqvarna XP+ is the most suitable new oil for those with the old generators.

Husqvarna is well known for manufacturing small machines that utilize two-stroke engines. This means they are well experienced in formulating the best oil too. This semi-synthetic oil meets all the latest requirements and standards as it is JASO-FD certified.

In addition, this oil has a fuel stabilizer, can operate at low temperatures. This ultimately results in better engine protection and less emission of smoke. Better still is the fact that this oil is very affordable.

Briggs & Stratton Oil

This oil has specifically been created to be used in Briggs &Stratton generators. It is also fit for use in four-cycle generator engines. Further, the API has classified this superior-quality detergent oil as SJ/CD.

The fact that this oil is suitable for the technical staff at Briggs & Stratton makes is ideal for us too.  This oil is highly praised as it is warranty certified and is okay for warmer temperatures. Its specifications include mineral oil. API SJ/CD classified, and SAE 30 oil type.

The Briggs & Stratton oil provides engine protection and is good for lubrication. It is very affordable and is a product the Americans is proud to call their very own.

Lastly, we also have a guide on How to Change Oil in Portable Generator available at our website.

Alexey P. , Qualified Electrician and Website Founder
Alexey P. , Qualified Electrician and Website Founder

My name is Alexey P. I was born in Poland but later moved to the USA in 1998. As a well-qualified and fairly experienced electrician, I love working with DIY projects. As a result of my professional training in the field of electrical engineering, I am well versed with the key elements of the trade. I am generally knowledgeable with all inspecting codes and important regulations governing electrical components and repair. I presently live in Dover, Delaware, USA. Want to know a little about my life outside work? It is no wonder. If you encounter any challenges with your portable generator while on that camping expedition, you can count on me to help deal with that decisively. I love life. I love people. And yes, I love generators, of course!

1 Comment
  1. Dear Sir:
    In looking at Brutes’ manual I find that SAE 5W30 Synthetic oil is the best choice. I bought some at Walmart as a five quart jug was most economical. The brand is Super Tech and it was in the automotive oil. At the risk of admitting ignorance I’m assuming there is nothing to be worried about and that any SAE 5W30 will work in my four stroke generator engine. Can you verify this please?

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