Exhaust manifolds — removal and installation
Note: Before beginning this procedure, allow the engine to cool completely, and apply penetrating oil to the manifold and converter fasteners.
Note: On 2.7L engines, the exhaust manifold is integrated into the cylinder head and the turbochargers bolt directly to the cylinder heads. On 2011 through 2014 3.5L and 3.7L models, the front exhaust manifold and the catalytic converter are integrated into one piece. On 2015 and later 3.5L models, both exhaust manifold, are integrated with the catalytic converters.
Front exhaust manifold
1. Disconnect the cable from the negative battery terminal (see Engine electrical systems).
2. Disconnect the electrical connector for the oxygen sensor and the catalytic converter monitor (see Emissions and engine control systems).
3. On 2015 and later models, remove the cooling fan shroud assembly (see Cooling, heating and air condition systems).
4. Raise the front of the vehicle and sup- port it securely on jack stands.
5. From below, disconnect the exhaust Y-pipe.
6. Remove the heat shield over the front exhaust manifold.
7. Remove and discard the six nuts securing the exhaust manifold (see illustration). Remove and discard the manifold gasket.
6.7 Remove the front exhaust mounting nuts from the studs (four of six shown)
8. Remove the exhaust manifold and converter.
9. Using a stud holding tool (available at auto parts stores) or a pair of nuts tightened together over a stud, extract the exhaust manifold studs and discard them.
10. Using a scraper, remove all old gasket material and carbon deposits from the manifold and cylinder head mating surfaces. If the gasket was leaking, check the manifold for warpage and have it resurfaced if necessary.
Caution: Be very careful when scraping on aluminum engine parts such as the cylinder heads. Aluminum is soft and gouges easily. Severely gouged parts may require replacement.
11. Install new exhaust manifold studs with light oil on the threads, then install a new manifold gasket over the studs. Install the manifold and new self-locking nuts.
12. Tighten the nuts, starting with the center fasteners and working towards the ends, to the torque listed in this Chapter’s Specifications.
13. The remainder of installation is the reverse of removal.
Rear exhaust manifold
14. Disconnect the cable from the negative battery terminal (see Engine electrical systems).
15. Disconnect the connector to the rear bank oxygen sensor.
16. Raise the vehicle and support it securely on jack stands.
17. Remove the Y-pipe-to-catalytic converter flange nuts and disconnect the Y-pipe. On 2014 and earlier models, remove the rear-bank catalytic converter.
18. Remove and discard the six exhaust manifold mounting nuts and remove the manifold from the engine. Remove and discard the manifold gasket.
19. Using a stud holding tool (available at auto parts stores) or a pair of new nuts tightened together over a stud, extract the exhaust manifold studs and discard them.
20. Using a scraper, remove all gasket material and carbon deposits from the exhaust manifold and cylinder head mating surfaces.
Caution: Be very careful when scraping on aluminum engine parts. Aluminum is soft and gouges easily. Severely gouged parts may require replacement. If the gasket was leaking, check the manifold for warpage and have it resurfaced if necessary.
21. Install new exhaust manifold studs with light oil on the threads, then install a new manifold gasket over the studs. Install the manifold and new self-locking nuts.
22. Tighten the nuts, starting with the center fasteners and working towards the ends, to the torque listed in this Chapter’s Specifications.
23. The remainder of installation is the reverse of removal.