Subaru Ascent PCV Valve Failure and Excessive Oil Consumption
Owners of 2019-2024 Subaru Ascents report excessive oil consumption and blue smoke caused by a faulty PCV valve drawing oil into the FA24F turbo engine's intake tract.
Last updated: 2026-05-15
What goes wrong
Under high-boost or high-vacuum conditions, the PCV valve sticks open or fails to seal. This creates a vacuum leak that sucks liquid oil from the crankcase into the intake system. The oil is then burnt in the combustion chamber, leading to carbon buildup on valves (LSPI risk), fouled plugs, and potential catalytic converter damage over time.
Symptoms to watch for
- Low oil level light illuminating before the next scheduled service.
- Visible blue or grey smoke from the exhaust during cold starts or heavy acceleration.
- Oily residue found inside the intercooler or throttle body.
- Rough idling or 'stumbling' during deceleration.
- Reduced fuel economy and spark plug fouling.
Root cause
The FA24F turbocharged engine generates high crankcase pressures that the original PCV (Positive Crankcase Ventilation) valve may fail to regulate. A sticking or failed valve allows atomized oil to be pulled directly into the intake manifold and turbocharger, where it is consumed during combustion.
Buy time with these
- • Check engine oil levels every 1,000 miles via the dipstick.
- • Shorten oil change intervals to 3,000-5,000 miles using high-quality full synthetic 0W-20 oil.
- • Install a high-quality baffled oil catch can system to prevent blow-by from reaching the intake.
Permanent fix
- Replacement of the original plastic-body PCV valve with the updated metal-body or reinforced design (Part #11810AA150 or latest supersession) and inspection of the PCV hose for softening or collapse.
Related recalls / TSBs
FAQ
What causes subaru ascent pcv valve failure and excessive oil consumption?
The FA24F turbocharged engine generates high crankcase pressures that the original PCV (Positive Crankcase Ventilation) valve may fail to regulate. A sticking or failed valve allows atomized oil to be pulled directly into the intake manifold and turbocharger, where it is consumed during combustion.
How much does it cost to fix?
National average $95–$250. Costs assume dealership labor rates of $150-$180/hr; the part itself is approximately $15-$30. If oil fouling has damaged spark plugs, add $300-$400.
Is this a DIY repair?
Difficulty 2/5. Replacement of the original plastic-body PCV valve with the updated metal-body or reinforced design (Part #11810AA150 or latest supersession) and inspection of the PCV hose for softening or collapse.
What are the symptoms?
Low oil level light illuminating before the next scheduled service.; Visible blue or grey smoke from the exhaust during cold starts or heavy acceleration.; Oily residue found inside the intercooler or throttle body.; Rough idling or 'stumbling' during deceleration.; Reduced fuel economy and spark plug fouling.