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How to Select the Right Grade Oil for Generac Generators?

Generac generator

Using the right grade oil is important to ensure efficient generator operation. Here you will learn about selecting the best oil for your generator.

Tips for Selecting the Best Generator Oil

Generators use the same type of oil as used in cars. You must consider similar factors such as the viscosity of the oil and temperature range in selecting the right oil for your generator. Here are some factors that should be considered to select the right generator oil.

SAE Grade

You must consider the SAE Grade of the oil when purchasing engine oil. SAE is the acronym of the Society of Automotive Engineers that grades oils. The grading is done based on the viscosity of the oil at different temperatures.

SAE10W oil is a grade of oil that flows smoothly at a temperature range between -10 and 40 degrees F ( -23 and 4 degrees C). SAE 30 grade oil, on the other hand, has a working temperature range between 32 and 105 degrees F (0 to 45 degrees C). These two-grade oils are suitable for most people in cold and temperature regions.

SAE 5W-30 is a more pricey engine oil that is recommended for regions with extreme temperatures. The oil has a temperature range between -30 and 122 degrees F (-34 and 50 degrees C). But remember that the oil results in increased consumption at higher temperatures. So, it is important to check the oil more regularly if you use this grade of oil.

API Specification

API stands for the American Petroleum Institute. You should buy a generator oil with the right API classifications.

Generator oil can have different API specifications such as SJ, SL, SM, SN, and SN+. Avoid using engine oil with older classifications such as SA, SB, SC, SD, and SE. These engine oils are recommended for older brand generators.

Engine oils with SN and SN+ classifications are the best grade oil for generators. These engine oils have improved sludge control and temperature deposit protection for internal engine components. Using engine oil with SN and SN+ API classification can result in improved emission control compatibility, reduced wear and tear, and enhanced fuel economy. You can also find generator oils with a combination of SJ, SN, and other grades.

Original Equipment Manufacturer (OEM) Specification

You should select a reliable generator oil brand that is recommended by the generator manufacturer. This is important to ensure the best quality generator oil. Some of the recommended generator oil brands include Briggs & Stratton, Honda, Onan, and Shell Rotella.

The cost of reliable brands may be higher. But it will be safer for your generator due to high-quality oil. Generac Motor Oil is recommended for Generac and Decatur generators. If you have a Honda Generator, you should consider Honda Oil.


Using the right grade oil is recommended for efficient generator operations. You must use SAE 30 engine oil if the temperature in your area does not go below freezing temperature (32 degrees F or 0 degrees C). SAE 10W-30 generator oil is suitable for moderately cold areas.

You should select SAE 5W30 grade oil if residing in a region with extreme temperatures.

Remember that gasoline engine oil must be changed after the first 20 hours of operation. Thereafter, you must change the oil after every 50 hours.

Generac Superstore deals with Generac, Decatur generators, and many other brands. We offer professional generator service in Huntsville, AL. Contact us today for all types of generator repair and maintenance services.


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