If you're experiencing serious Subaru head gasket problems, the only permanent solution would likely be to replace the head gasket itself. However, this is a very costly fix, especially for a Subaru. To be fair, the head gasket (just the gasket, i.e. parts only) can often be found for around $100 to $200. Sometimes, even less, depending on what specific Subaru engine you're fitting it to. However, the reason why you'll usually end up paying $1,000++ for a Subaru head gasket replacement is the labor required. Changing the head gasket will require major disassembly of the engine, which can take a lot of time. Experienced mechanics will take at least 6 hours to perform this job. Meanwhile, rookies or DIYers may take several days or even upwards of a week to replace the head gasket.