Ford 7T4Z-9431-C
Exhaust Manifold, Driver Side

A service or repair of the left-hand (LH) exhaust manifold starts with taking out the LH catalytic converter and the LH heated oxygen sensor (HO2S). The procedure starts with removing three bolts from the LH exhaust manifold heat shield and then it proceeds to take out the six nuts holding the LH exhaust manifold and discarding both the nuts and the gasket. Clean the LH exhaust manifold before studying its condition then dispose of its six LH exhaust manifold studs. The sealing surfaces require avoidance of metal scrapers and wire brushes or abrasive tools to prevent leaks because they can create scratches and gouges; use a plastic scraper and follow packaging instructions for proper cleaning of the exhaust manifold mating surface on the cylinder head. Six new LH exhaust manifold studs must be installed after which torques should be set to 12 Nm (9 lb-ft). A proper second-round torque on exhaust manifold nuts is crucial for stopping exhaust leakage. Install the LH exhaust manifold with six fresh nuts and tighten them through two stages by beginning with 20 Nm (15 lb-ft) followed by an additional 20 Nm (15 lb-ft). First maintain 14 Nm (10 lb-ft) torque when reattaching the LH exhaust manifold heat shield through three bolts before adding the LH HO2S and finally installing the LH catalytic converter.

A proper replacement or removal of the LH exhaust manifold starts with unfastening the LH catalytic converter along with its LH Heated Oxygen Sensor (HO2S). You must remove the 3 bolts that secure the LH exhaust manifold heat shield before taking out the 6 nuts which hold the LH exhaust manifold. Keep the nuts and gasket for disposal. The cleaning process needs to start with the LH exhaust manifold followed by an inspection then ending with discarding the 6 LH exhaust manifold studs. The use of metal scrapers and wire brushes or abrasive tools for sealing surface cleaning on the exhaust manifold should be avoided because such tools may produce leaks from scratches and gouges. Follow packaging instructions to clean the exhaust manifold mating surface on the cylinder head by using a plastic scraper with metal surface prep. The installation process requires the use of 6 new LH exhaust manifold studs which should be tightened to 12 Nm (106 lb-in). Installation of the LH exhaust manifold requires a new gasket which should be installed with six new nuts tightened in two stages to 20 Nm (177 lb-in) followed by 25 Nm (18 lb-ft). Reinstall the LH exhaust manifold heat shield by tightening its 3 bolts to 10 Nm (89 lb-in) and then install the LH HO2S followed by installing the LH catalytic converter.

Reconnect the RH HO2S electrical connector and reinstall the RH catalytic converter.

Using a new gasket, install the RH exhaust manifold with 6 new nuts, tightening them in two stages: first to 20 Nm (15 lb-ft) and then again to 20 Nm (15 lb-ft).

Use a plastic scraper and clean the exhaust manifold mating surface of the cylinder head with metal surface prep according to the packaging instructions.

Tighten the six new RH exhaust manifold studs to 12 Nm (106 lb-in).

Ensure the exhaust manifold nuts are tightened to specification a second time.

Using a new gasket, install the LH exhaust manifold with 6 new nuts, tightening them in two stages: first to 20 Nm (15 lb-ft) and then again to 20 Nm (15 lb-ft).

Install 6 new LH exhaust manifold studs and tighten them to 12 Nm (9 ft. lbs.). Using a new gasket, attach the LH exhaust manifold with 6 new nuts, tightening them in the specified sequence to 20 Nm (15 ft. lbs.).

Install six new RH exhaust manifold studs and tighten them to 12 Nm (9 lb-ft).

Remove the six nuts securing the RH exhaust manifold and discard both the nuts and the gasket.

Remove the six nuts securing the RH exhaust manifold and discard both the nuts and the gasket.