Don't listen to these faggots.
How many threads are there out there saying they need to put in some thicker oil to get correct lubrication?
What they don't realise is leaving your oil in your engine naturally thickens it up! The reason you don't have any showing on your dipstick, is that is is now stuck to your pistons giving permanent lubrication on cold startup. People pay massive bucks for 'castrol magnatec' to give the same 'clinging' powers, not realising all that castrol do is sell you some old recycled oil!
You'll find there is now a racing blend 15W60 in your motor. The check engine light has come on due to lack of limiter launches. (The
ecu expects a limiter launch and skid every 10,000km from your Subaru mechanic) Get onto this before the service and after the service to reset the
ECU.
P.S. Don't tell anyone these secrets otherwise the service industry will go into recession.