How Often to Change Oil in Generator? (Portable & Onboard)

generator oil change frequency

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Regular oil changes ensure the proper functionality, performance, and longevity of a generator. It is an important aspect of generator maintenance that can have detrimental outcomes if neglected.

So, how often to change the oil in a generator?

A generator’s oil change frequency mainly depends on the type of generator, usage, and oil type. Most portable generators need an oil change every 50-100 hours of use. Whereas, oil on an onboard RV generator will need to be changed every 100-150 hours of use.

In this post, we’ll take more about the frequency of oil change a generator needs. We’ll also look at the factors affecting the frequency of oil change and the benefits of a regular oil change.

How Often to Change Oil in Generator?

Most generator manufacturers recommend oil changes after specific hours of runtime. But other situations call for a complete change of the oil. 

A generator needs oil changes during the break-in process. You may need to change the oil multiple times to ensure the proper break-in of your generator. Check the owner’s manual of your specific model to know the recommendation.

Changing your generator oil during scheduled maintenance is a good practice. Generators that are used in dusty areas like deserts will require frequent maintenance and oil changes. Moreover, older generators need oil changes more frequently compared to a new unit.

You should consider changing the oil after a long camping trip with extensive generator use. Extended generator runtime with heavy loads will wear down the oil quickly, thus requiring frequent oil changes.

Unlike inverter generators, most non-inverter-type generators constantly run at the highest RPM irrespective of the load. This constant high-speed rotation of the engine breaks down the oil quicker, needing frequent oil changes.

Lastly, most inverter generators these days come with a low oil sensor that prevents the unit from starting if low oil is detected. This helps prevent engine damage. In such a case, check the engine oil level first, add or change the oil if needed.

However, you may need to change your generator oil once or twice a year if it gets a few hours of runtime on every camping trip. Make sure to check the fluid level, color, and viscosity of the oil to find out if it needs a change.

How Often to Change the Oil in Portable Generator?

Portable generators are the most common types of generators used for RV camping and boondocking. The oil change intervals on a portable generator vary depending on factors like use, environment, and brand of the unit.

To begin with, a portable generator will require multiple oil changes within the first few hours during the break-in process. Changing the oil a few times while breaking in removes the metal shaving from a new engine, thus extending its life.

Most portable generator manufacturers recommend a complete engine oil change every 50-100 hours of use. But this number can vary significantly if the unit is used continuously or run in a dirty environment.

Unlike onboard RV generators, portable generators sit low on the ground giving them full exposure to the dirt and debris around. This enables the dust and dirt to find their way easily into the generator increasing the frequency of maintenance including an oil change.

Moreover, brands like Honda, Champion, Generac, etc recommend an oil change every 100 hours of use. However, refer to the user manual of your generator to know otherwise.

How Often should I Change the Oil in my RV Generator?

RVs with onboard generators follow different oil change intervals. A brand new RV needs its first oil change at the 50 hours mark. Once the break-in process is complete, you need to change the oil every 100-150 hours of use.

Like portable generators, these numbers will also vary depending on the level of use and the condition of the generator. However, unlike portable generators, the role of the environment is a bit slim on the oil change on an onboard generator.

Onboard RV generators are housed in a dedicated generator compartment inside the RV which reduces exposure to dust, affecting the oil change frequency. Moreover, because they sit inside a compartment, they don’t get baked by direct sunlight, like a portable unit.

This also helps to deter the need for a frequent oil change as heat from the sun can’t aid in breaking down the oil. Though manufacturers like Onan recommend an oil change every 100 hours of use or every year, you can easily extend it to 150 hours by using it cautiously.

Does Synthetic Oil have Longer Oil Change Intervals than Conventional Oil?

The type of motor oil you use will also determine the frequency of oil change in your generator. Generally, generators using synthetic motor oil will need fewer oil changes compared to the same generator running conventional oil.

However, irrespective of the type of oil, the oil change frequency will depend on factors like the age of the generator, usage, load, and the brand of oil in use. Generally, the distance between the oil change intervals in synthetic vs conventional is pretty large.

Make sure you use the type of oil recommended by the manufacturer of your generator. Use Mobil 1, if you like to run synthetic oil in your portable generator and Cummins 3265336 for onboard RV generators.

What Affects the Frequency of Oil Change in Generators?

There are a wide variety of factors that play a role in oil change intervals. Of them, the most pronounced are the type of generator, its usage, and type of oil.

Let’s talk about each factor in detail.

Type of Generator

The generator type in question can greatly influence the oil change intervals. Generally, diesel-powered generators eat through the oil much quicker than gas-powered generators.

Likewise, a conventional generator will break down the oil easily compared to an inverter-type generator. Unlike inverter generators, conventional generators constantly run at their maximum RPM irrespective of the load. The high RPM produces a higher heat level, resulting in shorter oil life.

Moreover, the built quality of a generator’s engine can determine the frequency of oil change. A Honda generator will need less frequent oil changes compared to a Chinese-made generator in the same wattage rating.

Generator Usage

Extended runtime, high temperature, and the environment can affect oil life and consumption. Generators that are used less frequently will need fewer oil changes compared to generators that are used continuously during a camping trip.

Generators that are commonly used during the summer months under the hot sun will burn through the oil easily. This is because the heat from the engine along with the heat from the sun will break down the oil quickly.

Lastly, using generators in dusty or dirty conditions will require frequent oil changes as the dirt from the surroundings will damage the oil.

Type of Motor Oil

Generators and other engines use two types of motor oil, i.e. conventional oil and synthetic oil.

Conventional motor oil is not very refined and burns out easily. That means frequent oil changes and maintenance.

On the other hand, synthetic oil is specially formulated to last longer and be more stable at higher temperatures. Generators using synthetic oil, in general, will have a lower oil change frequency.

However, make sure to refer to your generator’s users manual before using one over the other.

What Happens if you Don’t Change the Oil in a Generator?

Oil is necessary for the proper functionality of the engine of your generator. It helps lubricate and protect the moving parts inside the engine of your generator.

Changing generator oil regularly is the easiest way to ensure peak performance and longer working life for your unit. However, failing or ignoring to change your generator oil on time can cost you both time and money.

Here are a few downsides of failing to change a generator’s oil on time.

Dirty or worn-out oil has gunk makes the regular movement of the engine’s internal components difficult, forcing it to work harder. As a result, the generator’s engine has to work harder and to compensate that uses more fuel.

Motor oil is a lubricant that helps minimize engine wear and tear caused due to friction. As the oil breaks down, it loses its lubricating properties increasing friction, speeding up the wear and tear on the engine, until it seizes.

Overall, scheduled oil changes help generators perform better and live longer.

Is it Good to Change Generator Oil Frequently?

Unlike the benefits of scheduled oil changes has, there are drawbacks to changing a generator’s oil too often. Or in other words, changing your generator’s oil too frequently won’t give much of a difference in the working of your generator.

Experts say changing the oil too frequently won’t make your generator last longer or improve its performance significantly. But, it is a waste in terms of time, money, and natural resources.

Changing generator oil too often will cost you extra time that could have been better used elsewhere. It will cost you additional money as you have to buy motor oil frequently. Lastly, frequent oil changes mean frequent oil disposal that will hurt the environment.

Therefore, change your generator oil when it is needed. Both doing it less or more frequently is bad.


Most manufacturers recommend 50-100 hours for portable generators and 100-150 hours for onboard RV generators. However, the frequency of oil change in a generator mainly depends on the type of generator, usage, and oil type.

Make sure to refer to your generator’s user manual to know more.