How to Replace the Exhaust Manifold in a Subaru Outback

Disconnect the negative battery cable and remove the air cleaner case (if present). Take out the front oxygen sensor and the front undercover, then remove the rear oxygen sensor electrical connector.

Remove the Y-pipe-to-pipe mounting nuts and take the Y-pipe from the rear pipe. Take out the bolts from the front Y-pipe where it is connected to the cylinder head. Separate the Y-pipe from the hanger bracket.

Pull the exhaust pipe from the catalytic converter and discard the gaskets. Clean all the gasket surfaces to remove gasket material, dirt and carbon deposits.

Wipe the mating surfaces with solvents. Check for damage to the surfaces.

Install new gaskets and then connect the front catalytic converter to the front exhaust pipe. Set the Y-pipe in place and temporarily tighten the bolt on the hanger bracket that holds the center exhaust pipe.

Connect the Y-pipe to the cylinder head and then adhere the Y-pipe to the rear pipe. Tighten the fasteners.

Return the center exhaust pipe to the hanger bracket then connect both the rear and front oxygen sensors. Replace the front undercover and reinstall the air cleaner case.

Connect the battery. Start the engine and allow it to warm up. Check for exhaust leaks.