The Nissan 3.3 engine's exhaust manifold collects exhaust from each of the valves and sends it through the exhaust pipe. The exhaust manifold must be in good condition to avoid harmful fumes from entering the cabin. If the vehicle's exhaust manifold has a crack in it, replace it as soon as possible.
Disconnect the negative cable from the battery using a wrench to loosen the nut on the terminal. Remove the heat shields from around the manifold using a wrench. Disconnect the EGR tube from the valve.
Unplug the electrical wire from the heated oxygen sensor by pulling it off. Disconnect the front exhaust pipes using a wrench to loosen the bolts. Remove the bolts from the exhaust manifold using a socket, ratchet and extension.
Remove the exhaust manifold with the catalytic converter still attached. Remove the catalytic converter from the manifold using a wrench. Attach the converter to the new manifold and tighten the bolts with a wrench.
Install the manifold to the engine and tighten the fasteners with a socket, ratchet and extension. Connect the front exhaust pipes using a wrench to tighten the bolts. Plug the electrical wire into the heated oxygen sensor.
Connect the EGR tube. Install the heat shields around the manifold and tighten the fasteners with a wrench. Connect the negative battery cable and tighten the terminal nut with a wrench.
