Best Oil for a Portable Generator (Top 5 Highest Quality)

Last Updated on October 19, 2022 by Manager Access

best oil for portable generator
When it comes to owning a portable generator, there are a few necessary maintenance routines to ensure that you get the longest lifespan possible.

One of the most important things? Check your generator’s oil level.

Low oil level can cause major damage to your generator, and using a low-quality oil risks damaging vital engine components.

While there are many oils to choose from for your generator, select top tier choices can give your portable generator’s engine the best protection possible.

Today, I am going to talk about how oil works in your generator, what to look for in a generator oil, and my top 5 generator oil suggestions.

What Does Oil Do for a Generator?

Before you try figuring out which oil will best suit your generator, you need to know what the oil does for your generator.

Gasoline portable generators utilize engines that require oil to run properly.

These engines use oil to lubricate the rotating assembly inside the engine to ensure that the moving metal pieces have a smooth, less resistant path.

This reduces engine wear and keeps your engine lasting for years to come.

Over time and with many uses, this oil can break down and become less effective. This can make your engine components more susceptible to wear and tear.

Following the manufacturer’s maintenance schedule for oil changes can greatly prevent any unwanted engine damage.

5 High-Quality Engine Oil I Recommend

1. Honda 08207 10W30 Motor Oil

The Honda 08207-10W30 Motor Oil has a 10W-30 rating. This indicates that you may use the oil in cold and hot temperatures. Upon using, the oil correctly lubricates and protects your lawnmower from corrosion and wear. Honda’s natural oil is made out of a unique combination of shear-stable additives and high-quality base stocks that Honda has devised to withstand viscosity and thermal breakdown.

Honda has also tested and certified the oil, explicitly designed for 4-stroke engines. It also satisfies and exceeds the API’s criteria. After 8 seasons on this oil, our Honda lawn mower is still running excellent and starts with a pull or two depending on how long it has rested between mowings.

We found that the oil effectively improves the performance of tiny engines while also extending their service life. It also works well with other Honda goods, so it looks to be your go-to oil for all of your Honda gear.

One thing to note is that this is not synthetic oil.


  • Suitable for all climates
  • Extends the life of the engine
  • Improved performance


  • It is best for Honda lawn mowers alone

2. Valvoline Advanced Full Synthetic SAE 5W-30 Motor Oil 5 QT

Nates Interactive Auto

We’ve been using other brands for our vehicle for years, but we just switched to Valvoline because of the value. Plus, our vehicle was overdue for an oil change, so we wanted to clean out all the old crud with cheap oil first. Well, we think we’re going to stay with Valvoline now! This is why.

Valvoline Advanced Full Synthetic Motor Oil has been precisely engineered to help protect your engine from heat, deposits, and wear. Valvoline Advanced delivers more detergents and dispersants for optimal sludge and deposit prevention, as well as quality ingredients that withstand high temperatures and friction under extreme driving situations, thanks to its advanced composition.

Even with the cold-start friendly lower viscosity rating of a 5W30 mix, it looks that your valves and pistons are correctly protected when things get heated in your engine.

Lower viscosity also implies that if your engine has a turbocharger or supercharger, your oil will be able to survive the more significant temperature extremes associated with high-performance equipment.

While this is a good option for modern vehicles with fewer than 125,000 miles on the odometer, older vehicles will benefit from the Valvoline’s high mileage mix’s improved detergent additives and protectants.


  • Made in the United States
  • 100% synthetic oil
  • Cold-start performance and protection are superior


  • Your engine may need a few break-in oil changes as it flushes out any existing buildup
  • In older engines with heavy mileage, it may not be effective

3. Briggs & Stratton 30W Engine Oil

Briggs & Stratton 30W Engine Oil is a high-quality detergent oil for engines. That means it lubricates and cleans your engine for better performance and longer life. You can rely on this oil to keep your Honda mower’s engine in excellent shape.

The oil is designed specifically for higher temperatures and is proportioned to meet the demands of current engines. This oil comes in a 48-ounce container designed for smaller engines like lawnmowers.

The oil in the container is plenty to use on your lawnmower multiple times. This oil is inexpensive and an excellent choice for anybody on a tight budget. This bigger bottle is less expensive than the smaller 6-pack bottles. Some of their items are more expensive; however, we discovered that this size was more cost-effective. The ATF has a high detergent content, so it cleans everything wonderfully – all you have to do is drain the old oil, replace it with fresh oil, and store it for the winter.


  • It is risk-free to use
  • Perfect for warmer weather
  • It’s ideal for engines with lesser displacements
  • It is reasonably priced


  • Not suitable for cold temperatures

4. Castrol 03129C EDGE High Mileage Motor Oil

Castrol EDGE high-mileage motor oil is designed to keep high-mileage cars operating longer, so it makes sense that it would also be a good option for your generator. However, there are more advantages than merely a longer lifetime. Extra fluid titanium technology is used in this oil, which boosts oil film strength by up to 30% while lowering breakdown.

You may anticipate improved fuel efficiency while using this oil. You won’t have to replace it as frequently as you would with non-synthetic oils since it’s a 100% synthetic recipe. This composition is also designed to be 10 times more resistant to oil thickening at high temperatures.

Granted, unlike some of the other oils on our list, Castrol EDGE high-mileage motor oil isn’t developed expressly for tiny engines, but that also means it’s a lot less expensive. And if we can trust it with our cars, there’s no reason we shouldn’t be able to trust it with our generators. Overall, we think this is the best generator oil we’ve seen this year.


  • Titanium technology that is more fluid
  • Fuel efficiency has improved
  • Oil film strength increased by 30%
  • 10X more resistance to oil thickening at high temperatures
  • The recipe is entirely synthetic


  • It’s not designed for tiny engines

5. Generac Full Synthetic Motor Oil 5W-30

As one of the biggest names in the generator industry, Generac has developed their own line of engine oil to use with their generators.

Generac is well known for providing high-quality generators for all types of applications, from home use to industrial use.

Continuing their brand’s high-quality offerings is their full synthetic engine oil, made specifically for Generac portable generators.

This oil was developed to provide Generac generator owners with the correct oil to use when it comes time for an oil change.

This specific oil is going to be fully synthetic which means it is a high-performing oil that is sure to keep your generator lasting longer.

It had a 5w-30 viscosity which is similar to vehicle engine oil.

This means it can be easily used in both winter and summer without problem.

Generac oil also exceeds all API and SN service classification requirements. While this is a common feature in most oils, it is worth mentioning as most people look for this rating on their oils.

The materials that make up this specific oil protect against the formation of sludge and varnish deposits. This is a great benefit for generators as many sit for long stretches without use.

The high-quality synthetic base is fortified with an advanced additive for optimum performance. It will also provide maximum protection against viscosity breakdown.


  • Works within a wide temperature range
  • Can also be used for standy generators


  • A bit expensive

What to Look for in a Good Engine Oil

The first thing that you should do when choosing an oil for your generator is checking your owner’s manual for the manufacturer’s recommendations.

Just about every generator will have a preferred oil for their specific engine to coincide with the warranty.

If you no longer have the manual, there are certain things that you can look for before making a purchase.


Shopping for oils for your generator can be quite intimidating as there are many types of oils to choose from.

One thing that you can always look for is name brand oils. Popular name brands of oil are usually going to be the higher-quality oils as they have a reputation to maintain.

If you can find the same brand of oil to match your generator’s engine, that’s even better! When in doubt, research the brand’s reviews.


When you look at the oil bottle (or specs online), one of the first things you are going to see is the viscosity. Viscosity is the measurement of how easily the oil pours at a specific temperature.

Thinner oils are going to have a lower viscosity and will be easier to pour in cold temperatures. Thicker oils will have a higher viscosity and will pour slower in cold temperatures.

Refer to your user manual for the proper viscosity for your generator’s engine.


Additionally, you can check for the authenticity of engine oil by looking for any type of ratings on the bottle. Most oil manufacturers will print any certifications and ratings that the oil has received to further prove the quality of the oil.

You can also check online for any reviews of the oil to see how other customers like it.

Conventional vs. Synthetic

There are a few types of oil you can choose from, the most popular being conventional and synthetic.

Conventional oil is going to be your everyday, standard oil that can be used in most applications with low miles.

If your engine is fairly new and does not require synthetic, conventional can be used and is a great, budget-friendly option.

Synthetic oil is going to be higher-quality, containing additives that make it perfect for higher mileage generators and engines that require synthetics.

It is usually on the more expensive side, but it is higher in quality.

Frequently Asked Questions

oil bottles

Can I use a different brand oil than my generator’s motor?

When it comes to mixing brands of oil and brands of engines, there are a few things to look for. First, check to see if your generator calls for a specific brand of oil or just a certain weight.

If it just says a weight, you can most likely get by with any top tier brand oil in the viscosity you need. However, if your generator calls for specific oil, stick to the manufacturer’s recommendations. When in doubt, give the generator manufacturer a call.

How often should I change my generator’s oil?

Changing your generator’s oil ensures that your generator will last as long as possible. When it comes to oil change intervals, you will need to reference your generator’s manual for the correct maintenance schedule.

On average, plan to change the oil every 50 hours of run time.

Many generators have a run time meter, but for those that don’t, you will need to keep track of the hours manually.

Generac Full Synthetic Motor Oil 5W-30






Easy of Use


Value for Money

8.0/10 is an independent review business. I am not affiliated with any manufacturers and do not accept paid reviews. When you buy through my links, I may earn a commission which helps me purchase more generators for testing. - Scott Krager

One comment

  1. Since portable generators run at 3600 RPM or so they got the nickname of “screamers”. That being the case I thought best to use Valvoline VR1 racing oil. After 9 years it still starts easy and runs well even running in 100 degree + heat for extended periods. Just my .02 worth.

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