Choosing the correct 2017 Subaru Forester oil type is fundamental to ensuring the longevity and peak performance of your crossover. This specific model year, part of the fourth generation, utilizes a horizontally-opposed "flat-four" engine that places unique demands on lubrication. Because these engines operate with a different geometry than standard V or I configurations, the viscosity and specifications of the oil must be precise to ensure adequate lubrication of the moving parts.
Manufacturer Specifications and Viscosity
For the naturally aspirated 2.5-liter engine found in the majority of 2017 Foresters, Subaru specifies 5W-30 viscosity as the optimal choice. This multi-grade rating is critical because the "5W" portion ensures the oil remains fluid in cold winter starts, reducing wear during the most damaging phase of engine operation. The "30" designation provides the necessary thickness at operating temperature to maintain a proper oil film between the pistons and cylinders, protecting the engine under stress.
Synthetic vs. Conventional Oil
While the 2017 Forester can run on conventional mineral oil, Subaru strongly recommends using a synthetic blend or full synthetic formulation. Synthetic oils offer superior thermal stability and resistance to oxidation, which is vital for the boxer engine that sits low in the chassis and is exposed to underbody heat. Using a high-quality synthetic 5W-30 will often result in better fuel economy, enhanced cold-weather performance, and extended drain intervals compared to older conventional oils.
Capacity and Filter Considerations
When performing an oil change, the total capacity of the 2017 Forester is approximately 4.4 quarts for the engine oil itself. However, it is crucial to remember that the oil filter holds an additional volume of used oil. Therefore, if you are changing the filter yourself, you will need to have roughly 5 quarts of new oil on hand to ensure the system is filled correctly after the old filter is removed and the new one is installed.
Turbocharged Models and High-Mileage Variants
If your specific trim level features the turbocharged 2.0-liter engine, the 5W-30 specification remains mandatory. Turbocharged engines operate at significantly higher temperatures and RPMs, making the thermal stability of a synthetic 5W-30 essential for preventing coking (oil turning into sludge) and ensuring the turbo bearings are adequately lubricated. For owners with higher mileage—specifically vehicles exceeding 75,000 miles—subaru offers a specific High Mileage formulation. This oil contains seal conditioners to prevent oil leaks and additional detergents to keep the aging engine clean.
