How Often Should You Change Generator Oil?

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You should change the generator oil of a portable generator after the first 20 to 30 hours of use and after that, every 50 to 100 hours of operation or 6 to 12 months if this comes first.

In standby generators, you should change the oil after the first 5 to 25 hours of use and after that, every 100 to 200 hours of operation or every 1 to 2 years.

Check your generator user manual to see what oil change interval is right for your specific model.

Additionally, make sure you use the right generator oil type and follow other generator maintenance guidelines.

How long will oil last in a generator?

According to popular portable generator brands, oil will last around 6 to 12 months in a portable generator.

According to popular standby generator brands, oil will last around 1 to 2 years in a standby generator.

You want to check the guidelines for your specific engine oil and generator to avoid early wear and tear and worse.

Additionally, due to limited generator oil capacity and usage intensity, you may need to replace your engine oil faster than the time frames above.

How long will synthetic oil last in a generator?

Synthetic oil will typically last around 6 to 12 months in a portable generator and 1 to 2 years in a standby generator.

Keep in mind that replacing your generator oil sooner can be necessary if you use it often enough.

Additionally, you can not always use synthetic oil in a generator without voiding the warranty. Check your user manual for the recommended oil types.

The recommended oil change interval for portable generators is after the first 20 to 30 hours of use and after that, every 50 to 100 hours of operation or 6 to 12 months if this comes first.

You should change the oil of a standby generator after the first 5 to 25 hours of use and after that, every 100 to 200 hours of operation or every 1 to 2 years.

Individual brands and usage types come with different oil change interval recommendations.

For example, you want to change your generator oil more often in hot temperatures and with heavy loads.

As you can see, how long oil can sit in a generator is not the only relevant detail. The way you use your machine will influence oil change intervals too.

What happens if you don’t change generator oil?

If you don’t change your generator oil, your machine will experience faster wear and tear or break down completely.

This is because old engine oil is not as effective as fresh engine oil.

Your generator can run out of engine oil too if you keep on using it without changing the oil.

In that case, modern generators will typically shut down automatically thanks to the built-in low-oil shutdown feature.

If your generator does not have this feature and runs out of engine oil it will experience the mentioned faster wear and tear or damage.

This applies to all types of combustion-based generators ranging from small inverter generators to big diesel generators.

In simpler words, you definitely want to learn how to change generator oil.

You should not forget about other generator maintenance guidelines either.

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Author:

Mats is the founder and head editor of Generator Decision. With a combination of critical thinking, tireless research, and a healthy interest in electronics he helps people find the right generators and how to use these. At this point in the journey, Mats has done research on hundreds of portable generators.