Ford 4L2Z-5F250-GA
Catalytic Converter

When servicing the catalytic converter do not apply oil or grease-based lubricants to the isolators because it will deteriorate the rubber and possibly cause the exhaust hanger insulator to separate from the exhaust hanger bracket while the vehicle operates. The torque prevailing design of exhaust fasteners needs new replacement parts with matching original numbers together with exact torque values to maintain exhaust component retention. Begin by placing the vehicle in NEUTRAL position while hoisting the vehicle before using a suitable supporting jack to hold the exhaust system. The exhaust clamp needs to be tightened only after ensuring the tab of the muffler outlet pipe fits inside the notched extension pipe. After unthreading the extension pipe to muffler assembly clamp nut and taking out the extension pipe isolator, secure all components with a torque of 48 Nm (35 ft. lbs.). The technician needs to remove muffler to catalytic converter assembly bolts, springs, and flag nuts, keeping the flag nuts for disposal before detaching the muffler assembly isolators during installation by tightening them to 40 Nm (30 ft. lbs.). The procedure starts by using a jack to support the transmission. The next steps include the removal of heat shield bolts which should be tightened to 20 Nm (15 ft-lbs) upon reinstalling and extraction of the plastic shield positioned on the right side of the crossmember which should be secured with 9 Nm (80 inch lbs). The procedure requires bottom-up removal of the four upper and four lower crossmember bolts tightened to 70 Nm (52 ft. lbs.) for each before removing the catalytic converter support isolator to transmission mount bolt (tightening to 90 Nm (66 ft. lbs.) for final installation). Removing the transmission nuts along with the transmission crossmember requires you to disconnect the catalyst monitor sensor and heated oxygen sensor electrical connectors. Clean the connecting surfaces on the manifold outlet flare and catalytic converter inlet flare while setting the catalytic converter near the rear outlet to prevent damage of flares and studs. When installing a fresh catalytic converter assembly the catalyst monitor and heated oxygen sensors must be removed and the threads of these sensors need lubrication with anti-seize compound before they are put into position. Tightly install the exhaust manifold stud nuts using 40 Nm torque before you reinstall them after discarding the catalytic converter unit. After aid with the replacement process, begin starting the engine before inspecting the exhaust system for any signs of leakage and making necessary adjustments to the system alignment.