Exhaust System Leak and/or Rattle Noise (Replace Exhaust Manifold Pipe and Install Hanger Bracket If Not Present)

Some customers may comment on an exhaust system leak and/or a rattle noise.

Engine vibration may cause the exhaust manifold pipe flange to fracture at the takedown attachment to the turbo outlet pipe.

Verify if the exhaust manifold pipe is cracked at the turbo outlet pipe attachment. If cracking is evident, replace the exhaust manifold pipe. If the exhaust manifold pipe needs replacement, you must also install an exhaust manifold pipe hanger bracket if one is not present. Use the following procedure and the parts numbers listed below.

If the exhaust manifold pipe is not cracked, there may be other contributing factors to this condition. Further diagnosis of the exhaust system may be required.

1. Raise the vehicle. Suitably support the vehicle. Refer to Lifting and Jacking the Vehicle (SI Document ID #812944).
2. Disconnect and remove the exhaust manifold pipe. Refer to the Exhaust Manifold Pipe Replacement 6.6L and 8.1L Engines removal procedure (SI Document ID #803674).
3. If an exhaust hanger bracket is not present on this vehicle, remove the two engine mount bracket bolts and perform steps 4, 5 and 6.
4. Install two new studs (1), P/N 15071457 to the transmission. These studs will be used to attach the exhaust manifold pipe hanger bracket, P/N 15162233.

Tighten
Tighten the studs to 85N·m(62 lb ft).




5. Install a new exhaust manifold pipe hanger bracket (2), P/N 15162233 to the studs.
6. Install two new nuts (3), P/N 11514598 to the exhaust manifold pipe hanger bracket.

Tighten
Tighten the nuts to 75N·m(55 lb ft).

7. Install a new exhaust manifold pipe, P/N 15114915. Refer to the Exhaust Manifold Pipe Replacement 6.6L and 8.1L Engines installation procedure (SI Document ID #803674).
8. Lower the vehicle.

Parts are currently available from GMSPO.

For vehicles repaired under warranty, use: