considering the "severe duty" duration from Subaru is 3,750 miles, which is suggested for all EJ engines, and you went almost 6K, that could be part of your issue.
Well you had me question it enough to go check my records and for a second I thought you may have been right.Well I see one issue already. The oil you are using is it the Valvoline max life full synthetic or the blend. I work for Valvoline and normally the ma life is a synthetic blend which is not appropriate for that engine
Perhaps cause I already had it.... why are you running "high mileage" oil on a car with 21k miles?
Sent from my SAMSUNG-SM-G890A using Tapatalk