Firman Generator Oil Type & Change Guide

If you buy through the affililate links in this article, we may get a commission at no cost to you. As an Amazon Associate, we earn from qualifying purchases. Check out our editorial guidelines to learn more.

Photo of author
Published On

Find out what oil types Firman generators need so you don’t mess up your investment and get the most out of it for years to come.

In standard situations, Firman recommends using 10W-30 automotive oil of API SJ quality or higher in their generators.

Additionally, they recommend full synthetic 5W-30 oil when operating your generator in below freezing temperatures.

Besides that, manuals also mention that you can use 5W-30 automotive oil for temperatures up to 30 degrees Fahrenheit (-1.1°C) and 10W-40 automotive oil for temperatures higher than 70 degrees Fahrenheit (21.1 °C).

In terms of oil change interval, Firman recommends changing the oil after the first 25 hours of use and every 100 hours of use after that (or annually if this comes first).

Recommended Firman Generator Oil Type

Recommended Firman Generator Oil Type

What kind of oil do Firman generators take?

To make sure your Firman generator works as desired and for a long time to come, you want to use the right oil types.

More specifically, Firman generators basically always take 10W-30 automotive oil of API SJ quality or higher (1).

Firman also recommends using full synthetic 5W-30 oil for temperatures below 40 degrees Fahrenheit (4.4°C).

It is worth noting that the manuals often note that you can use 5W-30 automotive oil in temperatures up to 30 degrees Fahrenheit (-1.1°C).

Similarly, you could use 10W-40 automotive oil for temperatures higher than 70 degrees Fahrenheit (21.1 °C).

Can you use synthetic oil in your Firman generator?

Some generator brands recommend regular automotive oils for certain parts of the experience like the break-in.

That being said, Firman does not mention anything about this (1).

However, it is worth mentioning that the only synthetic usable oil specified in the manuals is full synthetic 5W-30 oil.

In simpler words, Firman mentions you can use full synthetic 5W-30 oil in their generators.

When should you change the oil in your Firman generator?

Generator oil is not a set-and-done thing. You have to replace it in intervals to keep your machine functioning as desired.

Firman recommends changing your generator oil after the first 25 hours of use and then every 100 hours or annually, whatever comes first (2).

Some brands recommend only using automotive oil during this initial break-in period but Firman does not mention anything related to this.

Where to buy Firman generator oil

Firman sometimes mentions their “FIRMAN SAE 10W-30 API SL oil” but during my research, I did not find any USA-based retailers that offer this oil.

Instead, you can check your typical retailers for other high-quality oils (API SJ or higher) of the types mentioned throughout this article.

Recommended Firman Generator Oil Type

Recommended Firman Generator Oil Type

FAQ

Do Firman generators need oil?

Yes, similar to other brands, Firman generators need oil to function well.

What is the recommended oil type for the Firman 3650 generator?

10W-30 automotive oil is the recommended oil type for the Firman W03383 3650 generator in typical temperatures.

Additionally, Firman recommends using full synthetic 5W-30 oil in freezing temperatures.

What is the recommended oil type for the Firman 7500 dual fuel generator?

Generally, 10W-30 automotive oil is recommended for the Firman 7500 dual fuel generator.

Different recommendations can apply to unusual temperatures. For example, full synthetic 5W-30 oil in freezing temperatures.

What is the recommended oil type for the Firman 6700 generator?

Firman recommends generally using 10W-30 automotive oil in their Firman P06701 6700 generator.

That being said, in certain temperatures, other oil types could be even better.

For example, Firman recommends 5W-30 oil for freezing temperatures.

What is the recommended oil type for the Firman 3550 generator?

10W-30 automotive oil is generally the recommended oil type for the Firman P03501 3550 generator.

At the same time, other oil types could be better for certain situations.

For example, Firman recommends 5W-30 oil in freezing temperatures.

What is the recommended oil type for the Firman WH03242?

FIRMAN SAE 10W-30 API SJ oil is the recommended oil type for the Firman WH03242.

Firman mentions other high-quality detergent oils (API SJ or higher) of the right types are acceptable too.

For example, 5W-30 oil can be better in freezing temperatures.

Which oil is best for Firman generator?

10W-30 automotive oil is generally the best oil for Firman generators.

However, in freezing temperatures, 5W-30 oil can be better.

Recommended Firman Generator Oil Type

Recommended Firman Generator Oil Type

Photo of author

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.