Ford 4L2Z-5F250-A
Catalytic Converter

Service and repair procedures for the exhaust Y-pipe with dual catalytic converters start only when the vehicle remains in NEUTRAL position on a hoist. A suitable jack must support the exhaust system while you work. Unplug both heated oxygen sensor (HO2S) and catalyst monitor sensors through electrical connector removal. Unscrew all bolts that fasten the exhaust Y-pipe-dual catalytic converter to the muffler assembly before discarding bolts, nuts and gasket. The service requires the removal of the transmission support crossmember. On the right-hand side remove the exhaust Y-pipe-dual catalytic converter-to-exhaust manifold nuts and throw away the bolts before taking out the exhaust Y-pipe-dual catalytic converter. A layer of anti-seize lubricant should be applied onto the HO2S and catalyst monitor sensor threads before installing each piece while tightening them to 40 Nm (30 ft. lbs.). Start by installing new exhaust Y-pipe-dual catalytic converter-to-exhaust manifold nuts before positioning the exhaust Y-pipe-dual catalytic converter with these nuts installed loosely. Next install new gasket material followed by the bolts and nuts needed for the exhaust Y-pipe-dual catalytic converter-to-muffler connection point while keeping it loose initially. Install the transmission support crossmember while positioning the exhaust system properly before connecting the HO2S and catalyst monitor sensors electrical connectors. Use water-based lubricants on isolators while using fasteners with an identical part number to originals and maintain the strict torque values to ensure proper exhaust component retention.

Disconnect the catalyst monitor sensor electrical connector.