Short answer: The 2018 Forester uses 0W-20 full-synthetic oil for the common 2.5-liter engine, while the turbocharged 2.0-liter XT typically calls for 5W-30 synthetic. Always confirm with your owner’s manual or the under-hood label for your exact trim and climate.
Oil by engine type
The 2018 Forester offered two engines, and oil viscosity is engine-specific. The following outlines the typical specs for each engine.
2.5-liter engine (non-turbo)
The 2.5L engine in most 2018 Foresters requires 0W-20 full-synthetic motor oil. It should meet API SN or later and ILSAC GF-5 or GF-6 specifications. Using the correct viscosity supports fuel economy and cold-start performance.
- 0W-20 full synthetic oil
- API SN or later; ILSAC GF-5 or GF-6
Bottom line: Use 0W-20 synthetic oil for the 2.5L Forester to ensure proper protection and efficiency.
2.0-liter turbo engine (XT)
The turbocharged 2.0L engine in the 2018 Forester XT generally uses 5W-30 synthetic oil. This viscosity balances turbocharged performance with engine protection, though climate-specific allowances can appear in regional manuals. Always defer to your manual for the exact specification.
- 5W-30 synthetic oil (typical recommendation)
Bottom line: If you drive a Forester XT, plan on using 5W-30 synthetic oil, and verify the exact spec in your manual or with a Subaru dealer.
Additional notes
Regardless of engine, choose a high-quality synthetic that meets Subaru’s specifications and the latest API/ILSAC standards. Adhere to the recommended oil-change intervals and regularly check the oil level to maintain performance and warranty coverage.
Summary
The 2018 Forester uses 0W-20 synthetic oil for the 2.5L engine and 5W-30 synthetic oil for the 2.0L turbo XT. Always verify your trim’s exact requirement in the owner’s manual or on the under-hood label, and follow Subaru’s guidance for change intervals and oil-grade standards to keep your Subaru running smoothly.