Excessive Oil Consumption
Subaru Outback vehicles (2011-2015) with the FB25 engine may experience excessive oil consumption due to faulty piston rings, leading to premature engine wear and potential damage if ignored.
Last updated: 2026-05-15
What goes wrong
The FB25 engine in these Outbacks can consume oil at an accelerated rate, often much higher than expected. This is typically due to poorly manufactured or designed piston rings that fail to properly seal the combustion chamber. Over time, this leads to lower oil levels, which can cause increased friction and wear on internal engine components, potentially resulting in catastrophic engine failure if oil levels aren't meticulously maintained.
Symptoms to watch for
- Frequent need to add engine oil (every 1,000-3,000 miles)
- Blue smoke from the exhaust, especially on start-up or deceleration
- Illuminated low oil pressure warning light
- Check Engine Light with P0420 (Catalyst System Efficiency Below Threshold Bank 1) due to oil fouling the catalytic converter
- Rough idling or misfires (less common, but possible with severe oil fouling)
Root cause
The primary root cause is defective piston rings that allow engine oil to bypass the piston and burn in the combustion chamber. The oil control rings, in particular, may be prone to sticking or failing to maintain adequate tension against the cylinder walls.
Buy time with these
- • Regularly check engine oil levels (every 1,000 miles or sooner)
- • Carry extra engine oil for top-offs
- • Use correct viscosity engine oil (0W-20 synthetic)
Permanent fix
- Engine rebuild with updated piston rings and gaskets
- Engine replacement with a new or remanufactured long block
Related recalls / TSBs
FAQ
What causes excessive oil consumption?
The primary root cause is defective piston rings that allow engine oil to bypass the piston and burn in the combustion chamber. The oil control rings, in particular, may be prone to sticking or failing to maintain adequate tension against the cylinder walls.
How much does it cost to fix?
National average $3,500–$5,500.
Is this a DIY repair?
Difficulty 1/5. Engine rebuild with updated piston rings and gaskets
What are the symptoms?
Frequent need to add engine oil (every 1,000-3,000 miles); Blue smoke from the exhaust, especially on start-up or deceleration; Illuminated low oil pressure warning light; Check Engine Light with P0420 (Catalyst System Efficiency Below Threshold Bank 1) due to oil fouling the catalytic converter; Rough idling or misfires (less common, but possible with severe oil fouling)