2017 Outback 2.5i excessive oil consumption - is this normal?

ClearTheCode admin answer:

Excessive oil consumption in certain Subaru models, particularly those with the FB series 2.5L engine (like your 2017 Outback), has been a known concern for some owners. While a small amount of oil consumption is normal for any engine, needing to add a quart every 2,000-2,500 miles can be indicative of an issue that warrants investigation.

Here's what you should know and do:

1. Understand Normal vs. Excessive: Subaru generally considers consumption of up to 1 quart per 1,200 miles as within acceptable limits for some engines, but this can vary. Your rate is approaching that threshold.
2. Common Causes:
   • Piston Rings: The most common cause in these engines is often related to the design of the oil control piston rings, which can lead to oil bypassing into the combustion chamber.
   • PCV System: A clogged or faulty Positive Crankcase Ventilation (PCV) valve can also contribute to increased oil consumption.
   • Valve Stem Seals: Worn valve stem seals can allow oil to leak past the valves into the combustion chamber.
3. Diagnostic Steps:
   • Oil Consumption Test: The best course of action is to have a Subaru dealership perform an official oil consumption test. This involves topping off your oil, sealing the dipstick and oil fill cap, and having you return after a specified mileage (usually 1,000-1,200 miles) for them to measure the exact amount of oil consumed. This is crucial for warranty claims if applicable.
   • Check for TSBs: In the past, Subaru issued Technical Service Bulletins (TSBs) and even extended warranties for certain models related to oil consumption. While your 2017 model might be outside the primary range for the most common TSBs, it's worth checking if any apply to your specific VIN.
4. When to See a Shop:
   • Immediately: If you notice blue smoke from the exhaust (especially on startup or deceleration), a strong burning oil smell, or if your oil consumption suddenly increases dramatically.
   • Soon: Schedule an appointment with a Subaru dealership to initiate an oil consumption test. This will provide definitive data and guide the next steps, which could involve engine repair (e.g., piston ring replacement) if the consumption is deemed excessive and covered by any extended warranty or goodwill program. Ignoring excessive consumption can lead to premature wear on catalytic converters and other engine components.