Excessive oil consumption in your 2013 Subaru Forester at 150,000 miles is unfortunately common with the FB25 boxer engine. While Subaru addressed some oil consumption issues through revised piston rings in later production, many 2013 engines still experience this problem.
Subaru Oil Consumption Background
Subaru settled a class action lawsuit regarding oil consumption in 2014-2016 vehicles with the 2.5L engine, though the 2013 was excluded from settlement. The issue relates to piston ring design that allows oil past the rings into the combustion chamber.
How Much is Too Much?
Subaru's official position allows up to 1 quart per 1,200 miles. Most owners expect much less. At 150,000 miles, some increased consumption is expected, but more than a quart per 1,000 miles indicates significant ring or valve guide wear.
Contributing Factors
Extended oil change intervals worsen consumption as deposits accumulate on rings. Using non-synthetic oil when the engine specifies synthetic can increase consumption. The boxer engine's horizontal cylinder orientation may contribute to oil ring drainage issues.
Management Strategies
Check oil weekly and maintain proper level - running low causes further damage. Use Subaru-recommended 0W-20 synthetic oil. Consider more frequent oil changes (every 3,000-4,000 miles) to minimize deposit formation. Track consumption to catch any sudden increases indicating worsening problems.