03 subaru suddenly using oil

03 impreza 2.5L nonturbo, 104k miles. The car drives flawlessly and had never used oil until recently. Now, it seems to burn oil at about 1,000 to 1,500 miles a quart. The engine is clean outside with no leaks. I have been using Castrol GTX 10w-30 (not 5w-30) because our location, Bishop, CA, is not far from Death Valley and summer temeratures are only slightly lower. A Subaru service guy was emphatically against using 10w-40 based on the “tighter clearances in newer engines”. He suggested checking the pcv valve, which makes sense and I plan to do. Would appreciate your opinion regarding use of heavier weight oil in this high mileage car. Cars I’ve owned in the past (53 Chevy for example) definitely profited from using a higher viscosity.

Yes, you should check your PCV valve, as that could possibly lead to increased oil consumption. However, at 104k, using a quart of oil every 1,000 to 1,500 miles is not that unusual, and it probably falls within the broad category of “normal” oil consumption for that number of miles on the odometer.

Think of it this way: Owners of new or fairly new Audis are using that much oil every 1,000 miles, and the manufacturer says that this is normal!

Count your blessings, and check that PCV valve.

I understand that I should stay with the 10w-30 (per owner’s manual, BTW).