Lexus 25051-36080 Exhaust Manifold Converter Sub-Assembly

Disconnect the cable from the negative battery terminal. Raise the front of the vehicle and support it securely on jackstands. Working below the vehicle, remove the lower splash shields. Apply penetrating oil to the bolts holding the exhaust pipe to the manifold. After the bolts have soaked, remove the bolts retaining the exhaust pipe to the manifold. Separate the front exhaust pipe from the manifold. Unbolt the lower exhaust manifold braces and remove them from the engine. Also, disconnect the oxygen sensor connectors. Working in the engine compartment, remove the upper heat shield from the manifold. Remove the nuts and bolts and detach the manifold and gasket. Use a scraper to remove all traces of old gasket material and carbon deposits from the manifold and cylinder head mating surfaces. If the gasket shows signs of leaking, check the manifold for warpage with a straight edge. If the manifold is warped, it must be replaced. Position a new gasket over the cylinder head studs, noting any directional marks or arrows on the gasket that may be present. Install the manifold and thread the mounting nuts into place. Working from the center out, tighten the nuts or bolts to the torque in three or four equal steps. Reinstall the remaining parts in reverse order of removal. Run the engine and check for exhaust leaks.