Lexus 25052-20190 Exhaust Manifold Converter Sub-Assembly, No.2

Models from 2004 and later come with exhaust manifold/catalytic converter assemblies, while those from 2003 and earlier have separate catalytic converters. Begin by disconnecting the cable from the negative terminal of the battery. Apply penetrating oil to the exhaust manifold fasteners and let it soak. For the rear exhaust manifold removal, elevate the front of the vehicle and secure it on jackstands, then take off the engine splash shields. Remove the heated oxygen sensors from the manifold, followed by the bolts and heat shield over the exhaust manifold if applicable. Take off the exhaust manifold brace if present, and then remove the nuts that hold the exhaust pipe to the manifold. Unbolt the manifold from the cylinder head, starting from the ends and moving toward the center, and carefully slip it off the mounting studs. Inspect the manifold and fasteners for any cracks or damage, and use a scraper to eliminate old gasket material and carbon deposits from the mating surfaces. If there was a gasket leak, check for warpage on the cylinder head mounting surface using a straight edge and feeler gauge; if the clearance exceeds the limit, have the manifold resurfaced. Position a new gasket over the cylinder head studs, install the manifold, and thread the mounting nuts into place, tightening them from the center outward. Reinstall all removed parts in reverse order, using new gaskets for the exhaust pipe connections, and finally, run the engine to check for any exhaust leaks.

On 2GR-FKS engines, the catalytic converters are integral with the exhaust manifolds, and the following procedure applies to either exhaust manifold. Begin by disconnecting the electrical connectors from the left upstream oxygen sensor. Next, remove the bolts securing the exhaust manifold support bracket and take it off. Disconnect any interfering wire clamps and remove the heat shield from the front exhaust manifold. Evenly loosen the nuts securing each exhaust manifold and then remove the manifold. Discard the old exhaust manifold gasket. For installation, reverse the removal process using a new gasket, ensuring the oval-shaped protruding tip faces the correct direction: it must face to the rear for the left manifold and to the front for the right manifold. Finally, tighten the exhaust manifold nuts gradually, starting from the center nuts and working outward, to the specified torque.

Before lifting the exhaust manifold, the first thing that should be done is to disconnect the cable of the battery's negative terminal. Lift the front of the vehicle and set it on jackstands safely and then, take off the lower splash shields and front floor cover from the left side. Pry these bolts loose while being very careful not to remove the oxygen sensors by applying penetrating oil on the bolts that hold the exhaust pipe to the manifold and allowing them to soak before removal. Unfasten the exhaust neck from the manifold, undo the down exhaust manifold girders, and unsnap the connectors on the oxygen sensor. Situated in the engine compartment, it is necessary to take off only the upper heat shield from the manifold while observing that the last type of heat shield is not required to be detached. Remove the nuts/bolts and take off the manifold along with its gasket. For installation you will use a scraper to scrape the mating surface of the manifold and cylinder head cleaning it and during this process you will check for warpage if the gasket is in bad state and it is leaking. If changing a manifold only, bolt the lower heat shield onto the new one. Place a new gasket over the studs on the cylinder head and ensure the manifold is fitted Thread the mounting nuts starting with the middle one before you tighten all of them. Replace the rest of the parts in the reverse order you removed them, starting the engine to check for leakages through the exhaust.

Replacement procedures vary based on model year and engine type. Always ensure the catalytic converter has cooled before servicing to avoid injury.

Replacement procedures vary based on model year and engine type. Always ensure the catalytic converter has cooled before servicing to avoid injury.

THERE ARE NO NOTES SAYING OTHERWISE