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Home >> Audi >> 2012 >> Q7 3.0 TDI >> Repair and Diagnosis >> External Pages >> Different car >> Section 30 (4.2L - Exhaust System & Emission Controls - Engine Code: Bar) >> 26 Exhaust System, Emission Controls >> Description And Operation >> Exhaust System Overview

Exhaust System Overview

WARNING: This page is about a different car, the 2010 Audi Q7, 2009 Audi Q7, 2008 Audi Q7, and 2007 Audi Q7. However, it is still accessible from the selected car via links, so may be relevant.
NOTE:

After exhaust system repairs, make sure exhaust system is not under stress and is far enough from the body. If necessary, loosen clamping sleeves and align mufflers and exhaust pipes so that there is adequate distance to vehicle body, and weight is evenly distributed among the exhaust hangers.

Primary catalytic converter and main catalytic converter

Fig 1: Catalytic Converters, Oxygen Sensors And Attachments, Assembly Overview
GWWA26-10279Courtesy of AUDI OF AMERICA, LLC
  1. Main Catalytic Converter
  2. Gasket
    • Replace
  3. Nut
    • Tightening specification: 23 Nm
    • Replace
  4. Primary Catalytic Converter
    • For right side of vehicle
    • With flex joint
    • Do not bend the flex joint more than 10° or it will get damaged.
    • Protect from shocks and impact stress
    • Removal and installation, refer to RIGHT PRIMARY CATALYTIC CONVERTER 
    • Install exhaust system free of stress, refer to EXHAUST SYSTEM, INSTALLING 
  5. Gasket
    • Replace
  6. Exhaust Manifold
  7. Nut
    • Replace
    • Tightening specification: 23 Nm
  8. Heated Oxygen Sensor (HO2S) -G39- (before catalytic converter)
  9. Oxygen Sensor (O2S) after Three Way Catalytic Converter (TWC) -G130-
  10. Nut
    • Tightening specification: 23 Nm
    • Replace
  11. Exhaust Manifold
  12. Gasket
    • Replace
  13. Heated Oxygen Sensor (HO2S) 2 -G108- (in front of catalytic converter)
  14. Primary Catalytic Converter
    • For left side of vehicle
    • With flex joint
    • Do not bend the flex joint more than 10° or it will get damaged.
    • Protect from shocks and impact stress
    • Removal and installation, refer to LEFT PRIMARY CATALYTIC CONVERTER 
    • Install exhaust system free of stress, refer to EXHAUST SYSTEM, INSTALLING 
  15. Oxygen Sensor (O2S) 2 after Catalytic Converter -G131-
  16. Nut
    • Tightening specification: 23 Nm
    • Replace
  17. Gasket
    • Replace
  18. Main Catalytic Converter
  19. Suspended Mount
    • Replace if damaged
  20. Bolt
    • Tightening specification: 23 Nm
  21. Suspended Mount
    • Replace if damaged
  22. Tightening specification: 23 Nm
  23. Suspended Mount
    • Replace if damaged
  24. Bolt
    • Tightening specification: 23 Nm
  25. Suspended Mount
    • Replace if damaged
  26. Bolt
    • Tightening specification: 23 Nm

Center Muffler and Rear Muffler

Fig 2: Identifying Center Muffler And Rear Muffler
GWWA26-10280Courtesy of AUDI OF AMERICA, LLC
  1. Bolt
    • Tightening specification: 23 Nm
  2. Suspended Mount
    • Replace if damaged
  3. Nut
    • Tightening specification: 23 Nm
  4. Rear Clamping Sleeve 
    • For individual replacement of center and rear mufflers
    • Installed location, refer to Fig 4
    • Before tightening, align exhaust system tension-free, refer to EXHAUST SYSTEM, INSTALLING 
    • Tighten threaded connections evenly.
  5. Nut
    • Tightening specification: 23 Nm
  6. Rear Clamping Sleeve 
    • For individual replacement of center and rear mufflers
    • Installed location, refer to Fig 4
    • Before tightening, align exhaust system tension-free, refer to EXHAUST SYSTEM, INSTALLING 
    • Tighten threaded connections evenly.
  7. Bolt
    • Tightening specification: 23 Nm
  8. Suspended Mount
    • Replace if damaged
  9. Nut
    • Tightening specification: 23 Nm
  10. Front Clamping Sleeve 
    • Installed location, refer to Fig 3
    • Before tightening, align exhaust system tension-free, refer to EXHAUST SYSTEM, INSTALLING 
    • Tighten threaded connections evenly.
  11. Nut
    • Tightening specification: 23 Nm
  12. Front Clamping Sleeve 
    • Installed location, refer to Fig 3
    • Before tightening, align exhaust system tension-free, refer to EXHAUST SYSTEM, INSTALLING 
    • Tighten threaded connections evenly.
  13. Center Muffler
    • Original equipment as one unit with rear muffler. For repairs, replace each separately.
    • Separating point, refer to Figure - Separate exhaust pipe at separating point -arrow- using VAS 6254 at a right angle.
    • Install exhaust system free of stress, refer to EXHAUST SYSTEM, INSTALLING 
  14. Suspended Mount
    • Replace if damaged
  15. Bolt
    • Tightening specification: 23 Nm
  16. Suspended Mount
    • Replace if damaged
  17. Bolt
    • Tightening specification: 23 Nm
  18. End Pipe
    • For left side of vehicle
    • Replacing, refer to TAIL PIPE .
  19. Rear Muffler
    • Original equipment as one unit with center muffler. For repairs, replace each separately.
    • Separating point, refer to Figure - Separate exhaust pipe at separating point -arrow- using VAS 6254 at a right angle.
    • Install exhaust system free of stress, refer to EXHAUST SYSTEM, INSTALLING .
  20. End Pipe
    • For left side of vehicle
    • Replacing, refer to TAIL PIPE .
Fig 3: Installed Position Of Front Double Clamps
GWWA26-10313Courtesy of AUDI OF AMERICA, LLC

-- Install clamping sleeves so that bolts are on bottom.

Fig 4: Installed Position Of Rear Double Clamps
GWWA26-10351Courtesy of AUDI OF AMERICA, LLC

-- Install the left clamping sleeve so the bolts are at the left.

-- Install right clamping sleeve so that bolts are at top.

Fig 5: Identifying Individual Suspension Components, Left Side
GWWA26-10314Courtesy of AUDI OF AMERICA, LLC
  1. Bracket
  2. Bolts - Tightening specification: 23 Nm
  3. Bolt - Tightening specification: 23 Nm
Fig 6: Identifying Individual Components Of Suspension, Right Side
GWWA26-10318Courtesy of AUDI OF AMERICA, LLC
  1. Bolt - Tightening specification: 23 Nm
  2. Bolt - Tightening specification: 23 Nm
  3. Tab
Fig 7: Front Drive Shaft Heat Shield
GWWA26-10311Courtesy of AUDI OF AMERICA, LLC

-- Tighten bolts -arrows- to 9 Nm.