One problem related to engine head gasket failure has been reported for the 2004 Subaru Outback. The most recently reported issues are listed below.
Multiple headgasket failure at 60,000 mile intervals since the car was new. It seems like the manufacturer is covering up a very bad engine design after looking online of very same reports. I am surprised with all of the complaints it is not been recalled or corrected. Unfortunately, due to costs of repair I am forced to scrap the car and find a different car company.