How do you replace a Volvo S80 head gasket?

Replacing the head gasket on a Volvo S80 requires several steps. First, disconnect the battery and drain the engine coolant. Then, remove the intake and exhaust manifolds, along with the cylinder head bolts, to access the head gasket. After cleaning the surfaces and ensuring there are no warps or cracks, place the new gasket, reassemble the components, and refill the coolant before starting the engine to check for leaks. Always consult a service manual for specific torque specifications and procedures.