How Often Should I Change My Generator Oil?

Contrary to popular belief, the answer to the question “how often should I change my generator oil” is… there is no magic one-size-fits-all oil change interval for generators.

Unfortunately, the recommended generator oil change interval can change dramatically from manufacture to manufacture, and from model to model.

For example, Duromax generators recommend that you change the oil in your generator after the first 6- 8 running hours to flush out the engine, and then every 20 hours after that (or after every 50 running hours for the XP15000E and XP15000EH).

On the other hand, the Honda EU2000i inverter generator recommends changing the oil after first 20 hours of use and then every six months after that.

While Generac recommends that you change the oil in your generator once a year or after 150 hours, whichever comes first.

FIRMAN recommends that you change the oil in your generator after the first 25 hours of use and then every 100 hours after that.

Champion recommends that you change the oil in a new generator after the first 5 hours of use and then every 50 hours or once a year, whichever comes first.

As you can see, there is a huge variation in the recommended maintenance schedule for changing the oil in your generator.

Which is why you should change the oil in your generator based on the maintenance schedule recommended by the manufacturer whenever possible.

You will typically find recommended oil change intervals in your owner’s manual or other operating instructions given to you at the time of purchase.

However, what do you do if you don’t have access to your owner’s or operator’s manual, are there any “rules of thumb” that you can follow when it comes to changing the oil in a generator?

How Often Should You Change The Oil In A Generator If You Don’t Have The Manual?

If you don’t have access to your owner’s manual, then…

How often you should change the oil in a generator depends on the answers to several important questions, including…

How many hours has your generator been used since the last oil change?

It is generally recommended that you change the oil in a brand-new generator after the first 6 – 8 hours of use to flush out the engine. After that, you should change the oil in your generator every 20 – 50 hours of use, more frequently under extreme operating conditions.

Does your generator have an oil filter?

Generators that have oil filters typically require fewer oil changes than generators without oil filters. If your generator has an oil filer, then it is generally recommended that you change your oil every 50 – 100 running hours.

Do you run your generator in dusty, wet or humid environments?

If you operate your generator in dusty, wet or humid environments, then you should consider changing your oil significantly more often than recommended under “normal” conditions.

What kind of load does your generator typically operate under?

Operating your generator for prolonged periods of time under a heavy load can put significantly more stress on both your generator and your oil. So, if you run your generator under heavy loads… consider changing your oil more often.

How long has it been since your last oil change?

Even if you haven’t been using your generator, your oil will degrade over time and provide less protection to your generator’s engine. That’s why it’s important to change your oil at least once every 6 – 12 months, even if you haven’t used it.

Final Thoughts On How Often To Change Oil In Generator

Basically, it comes down to this…

You should change the oil in your generator based on the oil change interval listed in your owner’s or operator’s manual.

If you don’t have your owner’s manual, then…

It is generally recommended that you change the oil in a new generator after the first 6 – 10 hours of operation, and then every 20 – 50 running hours or every six months, whichever comes first.

If your generator has an oil filter, then you can probably get away with changing your oil every 50 – 100 hours of operation or every twelve months, whichever comes first.

However, if you run your generator for a long period of time under a heavy load or in wet, humid or dusty conditions… you should change the oil in your generator more frequently.

And while you’re at it…

Check out our Generator Maintenance Tips article to learn more about how to get years of trouble free service out of your generator.