How many miles on it? I would recommend the dealer due to age of vehicle(still under warranty?) Oil 'consumption' test is basically starting with a fresh oil change and filter(using factory filter and specified oil) and verifying proper level , then bring it back at a specified interval (500-1000 miles?) to have it checked and see how much oil it takes to bring it to proper level. IF the amount needed exceeds manufacturers limits , then further action may be needed. JUST for reference-Honda's limit is 1 quart every 1,000 miles. WORST CASE-- this 'test' , if the end results do not result in warranty repairs, should only be the cost of a normal oil change.
Excessive oil consumption with the Forester is a known issue. Google it. I had 32,000 miles on my 2012 Forester and it was using oil. Dealer was great. No charge on the consumption test. I was using the equivalent of 28.5 oz per 3600 miles. Subaru said 32 oz was excessive. I kept at it and last week took it in again. Subaru is replacing the engine. No new car should use oil like that. I will give Subaru credit for standing behind their vehicle and doing the right thing.
