Q: How to remove and install the exhaust manifolds in V6 engine on 2012 Ford Fusion?
A: Before beginning this procedure, allow the engine to cool completely and apply penetrating oil to the manifold and converter fasteners. Most models have a catalytic converter that is an integral part of the exhaust manifold, and on 2.7L engines, the exhaust manifold is integrated into the cylinder head with the turbochargers bolting directly to the cylinder heads. To remove the front exhaust manifold, disconnect the cable from the negative battery terminal, disconnect the electrical connector for the oxygen sensor and the catalytic converter monitor, raise the front of the vehicle and support it securely on jackstands, disconnect the crossover pipe from below, remove the heat shield over the front exhaust manifold, and then remove the six nuts securing the exhaust manifold, discarding the manifold gasket and nuts. Next, remove the exhaust manifold, extract the exhaust manifold studs using a stud holding tool or a pair of nuts tightened together, and scrape off all old gasket material and carbon deposits from the mating surfaces, being cautious with aluminum parts. Install new exhaust manifold studs with light oil on the threads, place a new manifold gasket over the studs, and install the manifold with new self-locking nuts, tightening them starting with the center fasteners and working towards the ends. The remainder of the installation is the reverse of the removal procedure. For the rear exhaust manifold, disconnect the cable from the negative battery terminal, remove the EGR pipe from the exhaust manifold on 3.0L engines, disconnect the connector to the rear bank oxygen sensor, and remove the rear-bank catalytic converter on 3.5L engines, noting that the converter heat shield on AWD models with 3.0L engines requires the removal of the steering gear heat shield first. Remove the nuts from the exhaust manifold flange, separate the crossover pipe from the manifold, and then remove the six exhaust manifold mounting nuts to take the manifold off the engine, discarding the manifold gasket. Extract the exhaust manifold studs as before, scrape off all gasket material and carbon deposits, install new exhaust manifold studs with light oil on the threads, place a new manifold gasket over the studs, and install the manifold with new self-locking nuts, tightening them starting with the center fasteners and working towards the ends, completing the installation by reversing the removal procedure.