Choosing the Right Oil for Your 2009 Subaru Forester: A Comprehensive Guide

Subaru Forester is a popular compact crossover SUV that offers a combination of power, utility, and style. To ensure that your 2009 Forester operates smoothly and lasts for years to come, it’s essential to choose the right type of oil and regularly change it according to the manufacturer’s recommendations. In this article, we will discuss the various oil options available for your 2009 Subaru Forester and help you choose the right one based on your driving conditions and personal preferences.

Understanding Oil Viscosity and Weight

One of the critical considerations when choosing the right oil for your 2009 Subaru Forester is viscosity and weight. Viscosity refers to the oil’s thickness or resistance to flow, while weight refers to the oil’s density or thickness at a specific temperature. The proper oil viscosity ensures that your engine components are adequately lubricated and protected against wear and tear.

Subaru recommends using 5W-30 oil with a viscosity rating of API SM or higher for the 2009 Forester. This type of oil is suitable for most driving conditions, including cold climate, and provides optimal engine protection and fuel efficiency.

Conventional Oil

Conventional or mineral oil is the most commonly used oil and is readily available at almost all stores and service centers. It is made from crude oil and undergoes refining and processing to meet the API standards. It provides adequate protection and lubrication for most vehicles, including the 2009 Subaru Forester. However, Conventional oil has a shorter lifespan than synthetic oil and may require more frequent oil changes.

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Synthetic Oil

Synthetic oil is a more refined and advanced oil that offers better protection and performance than conventional oil. It is manufactured using chemical compounds and does not contain any impurities present in crude oil. Synthetic oil has a longer lifespan than conventional oil and can offer better engine protection, performance, and fuel efficiency. However, synthetic oil is more expensive than conventional oil but may be worth the investment in the long run.

High Mileage Oil

If your 2009 Subaru Forester has over 75,000 miles, you may want to consider using high mileage oil. This type of oil is designed to cater to the unique needs of vehicles with higher mileage and is excellent for preventing leaks and reducing oil consumption. High mileage oil contains additives that prevent seal hardening and reduce engine wear and tear.

Importance of Regular Oil Changes

Regardless of the type of oil you choose, it’s essential to change your 2009 Subaru Forester’s oil regularly. The oil’s effectiveness reduces over time, and debris, dust, and contaminants accumulate in the engine oil. This could lead to engine overheating, premature wear and tear, or engine failure. Subaru recommends changing the Forester’s oil every 3750 miles or 6 months, whichever comes first, under normal driving conditions.

Frequently Asked Questions

Q. Can I use higher viscosity engine oil in my 2009 Subaru Forester?

Ans: Using higher viscosity oil than recommended can lead to reduced fuel efficiency, increased engine wear, and decreased engine performance. Always use the recommended 5W-30 oil with API SM or higher viscosity rating in your Forester.

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Q. Is it worth investing in synthetic oil for my 2009 Subaru Forester?

Ans: Synthetic oil offers better engine protection, performance, and fuel efficiency than conventional oil. If you plan on keeping your Forester for an extended period, synthetic oil may be worth the investment in the long run.

Q. How often should I change the oil in my 2009 Subaru Forester?

Ans: Subaru recommends changing the Forester’s oil every 3750 miles or 6 months, whichever comes first, under normal driving conditions. If you frequently drive in harsher conditions, you may want to change the oil more frequently.


Choosing the right oil and regularly changing it is crucial to maintain the performance and longevity of your 2009 Subaru Forester. Synthetic oil is a better option if you want better performance and longer oil life, while conventional oil is a cost-effective alternative for everyday driving. High mileage oil is ideal for older vehicles with more than 75,000 miles. Always use the recommended oil weight and viscosity, and change the oil regularly as per the manufacturer’s instructions.

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Peter Banks

With years of experience as a professional mechanic and Subaru specialist, Peter is one of the most respected members of our team. He's written several articles on Subaru maintenance and repair, and his advice and tips are always practical and helpful. When he's not working on cars, he enjoys cooking and trying out new recipes.

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