A guide to monitoring Subaru engine oil use, separating external leaks from internal consumption and deciding when further testing is worthwhile.
Measure before guessing
Start with the correct oil level, note kilometres travelled and recheck consistently. A vague memory of adding oil does not establish a reliable consumption rate.
Check for external loss
Rocker covers, timing covers, sump areas and other sealing points should be inspected because leaked oil can account for part of the apparent consumption.
When to investigate further
Rapid oil use, smoke, fouled plugs, compression concerns or repeated low-oil events justify more detailed engine testing.
Need your Subaru assessed?
If a symptom is already present, a workshop inspection is more useful than trying to diagnose the vehicle from a generic guide. Vehicle condition, engine/transmission type and fault data can change the answer.