What Kind of Oil Does a Generator Use? (Find Out Now)

What Kind of Oil Does a Generator Use

Knowing about what kind of oil a generator uses is crucial for everyone. The reason is- adding the wrong one can cause leakage and even permanent damages (in some cases).

When this happens, you will then again have to spend around a thousand bucks to get a new generator.

Don’t worry; it won’t happen if you read my answer and follow this guide.

Generators use two kinds of oil- standard and synthetic. Standard oils are for almost every generator model, but synthetic ones are for the newer and more advanced ones.

Still, you can’t decide to use any oil for your generator. Many factors are involved in this decision, and I am discussing all of them in this article.

What Kind of Oil Does a Generator Use? Explaining in-depth

What Kind of Oil Does a Generator Use?

As I mentioned above, a generator uses two kinds of oil- Conventional and synthetic. Both are different, and it is super important to know their details if you own a generator.

Conventional Oils

Conventional or standard oils are most commonly used. Different companies manufacture them depending on the engine size and season. Yep, you can’t buy any conventional oil you like.

Their production is also interesting. Experts refine them from crude oil through different stages. These stages ensure the viscosity stays high, which most generators prefer.

I think the best part about standard oils is that you can use them for both newer and older models.

However, you will have to change them frequently if you want your generator to stay in good shape.

Synthetic Oils

We now have synthetic oils for generators too. They are specifically manufactured to provide the best lubrication. They are, in fact, lubricants that are engineered from chemical processes.

However, you can’t use them for all models. Synthetic oils are suitable for a few latest models. Also, they are more expensive than conventional oils. That’s why I don’t suggest them to those who have a tight budget.

But the thing is- Synthetic oils offer better performance than traditional ones.

Conventional vs. Synthetic Oil- Table of Comparison

I judged conventional and synthetic oils by considering eight factors. Here’s the result in the form of a table for you:


Conventional Oils

Synthetic Oils

Performance in Extreme Conditions

Have limitations under extreme conditions

Offers superior performance in all conditions.


Higher viscosity

Consistent viscosity

Cold Start Performance

Slower cold starts

Easier cold starts.


Requires more frequent oil changes

Longer service life


Requires more maintenance

Requires less maintenance


Generally more affordable



Compatible with engine components

Generally compatible, but verify manufacturer recommendations


Widely available


How to Choose the Right Oil for Your Generator?

I always do three things before deciding which oil I should get for my generator.

Checking Manufacturer Recommendations and Guidelines

First, I check whether the manufacturer has made any recommendations or issued any guidelines. If yes, then I always follow them (and so should you).

I highly praise Generac generators for taking care of their users. The company always prints about the right oil and has also issued the guidelines on the official website.

According to Generac, you should use SAE 30 if the temperature is above 34 degrees Fahrenheit. But if it is colder, Generac recommends using 10W-30.

Wondering what about Synthetic oil?

Well, Generac recommends Synthetic 5W-30, which can be used in all temperatures.

Considering the Generator Type and Model Considerations

Experts have divided generators into three types:

  • Portable Generators
  • Standby Generators
  • Inverter Generators

Each type has its own set of oil requirements. Therefore, I also advise you to know about them before purchasing the oil.

According to Generac, 5W-20 GEO Full Synthetic Oil is a great choice for your home standby. I think it is better for all gaseous engines. Plus, it is suitable for both cold and warm temperatures.

For portable and inverter generators, Generac recommends 5W-30 Full Synthetic Oil.

If you have generators from other companies, you can check the manuals or go online to see their recommendations.

Operating Conditions and Environment

Some oils are not suitable for higher altitudes. That is why you should go for those that can perform in all kinds of altitudes.

Luckily, synthetic oils do not have this limitation. However, a few standard oils may face trouble with oxidation in higher regions.

Similarly, I always recommend getting a dual-fuel generator, especially if you live in an area where storms are common. It is because the oil supply gets affected when the weather stays harsh for days.

In this situation, Propane can help you. You can store it in case of any emergency without any hesitation as it does not have a limited shelf life. When the oil supply gets restricted, you can take the stored Propane and use it to power your home.

Why Choosing the Right Oil For Generator Is Important?

Correct or right oil is super important for generators because of many reasons. Let’s have a look:

For Proper Lubrication

The main function of generator oil is to lubricate the engine parts. This helps these parts work properly, which leads to stable power supply.

For Smooth Heat Dissipation

Another thing I like about high quality oil is that it prevents any heat buildup within the generator. This is what keeps it running for hours smoothly. The reason?

Well, I think it has to do with Viscosity.

The right viscosity and thermal properties that take away the heat and start the cooling.

Cold Start Performance

Powering a generator in the cold is hard. However, if you use a top-quality oil, it becomes easy. It is because its viscosity ensures smooth starting.

But if you add inferior quality oil, you won’t be able to start the generator easily. You may even have to keep trying for hours in some cases.

Increase the Generator’s Life

The last reason why choosing the right oil is crucial is that the generator’s health depends on it. Let me explain.

High-quality oils have additives and detergents that control contaminants like dirt, sludge, and deposits. So they prevent the buildup of harmful substances and keep the engine clean.

Moreover, after researching, I also found that the generator oils contain anti-oxidation and anti-corrosion additives. They protect the engine from the damaging effects of oxidation and rust.

Therefore, always purchase the right and high-quality oil for the generators.

What Happens If You Use the Wrong Type of Oil?

What Kind of Oil Does a Generator Use?

10W-30 is recommended when the temperature is below 32 degrees Fahrenheit. Have you ever wondered what will happen if you add SAE 30 instead? Well, it can cause lots of problems, and you may have to call in a technician.

Similarly, if a generator only runs on gasoline and you add Propane, it can also lead to damage.

Let me discuss the damages in detail.


The first sign of wrong oil is overheating. It is because the friction between the internal components increases and heat dissipation slows down.

In my experience, generators will overheat within the first five minutes.

Leaks and Seal Damage

Using the wrong oil can also cause leakage and seal damage. In this situation, you will have to call a repairman/technician immediately to fix the generator.

Warranty Voidance

You cannot claim a warranty if you add the wrong oil. It’s because it’s your fault, and the manufacturer had nothing to do with it.

So, you will have to pay all the repairing and servicing costs.

Therefore, always handle oil-related matters with caution.

Additional Tips for Generator Oil Management

I have never faced any “oil-related” problems in my life because I always do everything correctly. Here are some of my tips for you to do better generator oil management:

Change Oil Regularly

You should regularly change the oil if you want your generator to keep powering your home appliances. I recommend people change the oil after the first 20-30 hours of operation. Afterward, I advise you to change every 100 hours of run time.

Note that the frequency of oil change depends on different factors, like heavy loads, extreme temperatures, etc. It is better if you read the manufacturer’s recommendations on this one.

Replace Oil Filter Timely

I also suggest you replace the oil filter regularly. The best time for it is with the oil change.

If you don’t replace it, the contaminations will start to build in the oil, which will impact the engine’s performance.

Store Oil Properly

Most people usually keep the oil in a garage. Well, there is no problem with it, but you should also make sure it is well-ventilated. Furthermore, the area should be clean and dry as well. This will ensure the oil stays in good quality.

Prevent Contamination At All Costs

You should also ensure no contaminants impact the oil quality. In most cases of contamination, the lid has a hole on the upper side or is not intact properly. Therefore, always seal the oil containers and then double-check.

I also suggest using pumps to transfer oils. This will ensure no moisture or air affects the quality.

Note the Label’s Expiry Date

Oils have expiry dates. You should keep them in mind and use them weeks before the deadlines. Mark my words- using expired oil will have the same impact as using the wrong oil.

Maintain Oil Records

Lastly, I recommend you maintain oil records. Always note down the date of the oil change, which one you used, and details about other maintenance tasks. Furthermore, you should also check the oil levels before starting a generator.

Follow my suggestions, and you will not face any “oil-related” problems in the future.

Related: What Kind of Oil Does a Generator Use?

Final Thoughts

All-inclusive, a generator uses standard and synthetic oils. Standard oil is cheaper and easily available. In comparison, Synthetic oil has stable viscosity and offers better performance.

However, you should always read the recommendations in the manual and consider environmental factors before deciding which one to buy!


Hi, Welcome to Generatorrookie.com; My name is Shahzad, and I know about generators because I grew up in a country where power outage is very common. I share Tips, How-To, News, and Reviews for the best generators or anything related to generators.

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