Subaru head gaskets. Everyone knows about it. The EJ series engines (pre-2011) had a real problem. The FA and FB engines that came after are better, but they have their own issues — oil consumption on the 2.5L, CVT shudder on the 2018-2019 models.
The factory manual has the head gasket replacement procedure, torque sequence, and the specific Subaru coolant conditioner that goes in after the job. Skip that conditioner and you’re back to square one in 2 years.
The CVT service procedure is also in there — Subaru calls for a fluid change every 25,000 miles under severe conditions. Most owners never do it and wonder why it shudders at 80,000 miles.
2022 Subaru Outback OEM factory manual covers the 2.5L and 2.4L XT. Older years back to 2009 also on the site.