Resonator

This procedure covers the removal and replacement of the exhaust resonator on the 2007-2013 Mercedes-Benz S65 AMG with the 6.0L V12 BiTurbo M275 engine.

Warnings

Tools required

Parts

• Exhaust resonator assembly × 1 — Use OEM specification
• Exhaust gaskets (if equipped at flanges) × 2 — Use OEM specification
• Exhaust rubber hangers (if damaged) × 2 — Use OEM specification

Preparation

1. Park vehicle on level ground and apply parking brake
2. Place wheel chocks behind rear wheels
3. Allow exhaust system to cool completely (minimum 2 hours after last operation)
4. Raise vehicle using floor jack at manufacturer-specified lift points
5. Support vehicle securely on jack stands rated for vehicle weight (approximately 5,000 lbs)
6. Apply penetrating oil to all exhaust clamps, flange bolts, and hanger bolts
7. Inspect resonator location from underneath - positioned between catalytic converters and rear mufflers

Procedure

1. 1

   Access the resonator assembly
   Locate the resonator in the mid-section of the exhaust system. On the S65 AMG, the resonator is positioned between the front catalytic converters and the rear muffler assembly. Identify the forward flange connection, rear clamp or flange connection, and rubber hanger mounts supporting the resonator.
2. 2

   Disconnect forward flange connection
   Locate the forward flange bolts connecting the resonator to the catalytic converter outlet pipe. Support the resonator with one hand or a suitable stand. Remove the flange bolts using appropriate socket. Carefully separate the flange connection, noting the condition of any gasket present.
   Torque spec

   Flange Bolts45 Nm (33 lb-ft)
3. 3

   Disconnect rear connection
   Identify the rear connection type (either flanged or clamped). If using exhaust clamps, loosen the clamp bolts completely. If flanged, remove the flange bolts. Do not fully separate the connection yet; maintain support of the resonator assembly.
   Torque spec

   Exhaust Clamps55 Nm (41 lb-ft)

   Flange Bolts45 Nm (33 lb-ft)
4. 4

   Remove rubber hanger supports
   Locate the rubber hangers supporting the resonator assembly (typically 2-3 hangers). Use a rubber exhaust hanger tool or pry bar to carefully unhook the exhaust hangers from the chassis mounting points. Work methodically to avoid damaging the rubber hangers if reusing. Note the orientation of hangers for reinstallation.
   ⚠Ensure resonator is properly supported before removing final hanger to prevent sudden drop.
5. 5

   Remove resonator assembly
   With all connections disconnected and hangers released, carefully lower and remove the resonator assembly from the vehicle. The assembly may be heavy; use proper lifting technique or have an assistant help. Inspect all mounting points, hangers, and connection surfaces for damage or excessive corrosion.
6. 6

   Clean and prepare connection surfaces
   Use a wire brush to clean the flange surfaces at both the front catalytic converter outlet and rear exhaust pipe connection. Remove old gasket material, carbon buildup, and corrosion. Inspect flange surfaces for warping or damage. Clean the chassis hanger mounting points.
7. 7

   Install new resonator assembly
   Position the new resonator assembly under the vehicle, aligning it with the mounting points. If equipped with gaskets, install new gaskets at the flange connections. Connect the rubber hangers to the chassis mounting points, ensuring proper orientation. The resonator should hang naturally with minimal stress on connections.
   ℹ️Do not fully tighten any fasteners until all connections are made and alignment is verified.
8. 8

   Connect forward flange
   Align the forward flange with the catalytic converter outlet pipe. Install flange bolts hand-tight, ensuring even engagement. Verify proper gasket seating if equipped. Apply anti-seize compound to bolt threads if desired.
   Torque spec

   Flange Bolts45 Nm (33 lb-ft)
9. 9

   Connect rear connection
   Align and connect the rear connection to the downstream exhaust pipe. If using clamps, position the clamp properly over both pipes ensuring equal overlap. If flanged, align the flange and install bolts hand-tight. Verify alignment before proceeding.
   Torque spec

   Exhaust Clamps55 Nm (41 lb-ft)

   Flange Bolts45 Nm (33 lb-ft)
10. 10

    Verify alignment and clearances
    With all connections hand-tight, verify the resonator assembly has proper clearance from the chassis, fuel lines, brake lines, and driveshaft. Check that rubber hangers are not twisted or over-stressed. Adjust position as necessary by loosening connections and repositioning. Ensure minimum 25mm clearance from all heat-sensitive components.
11. 11

    Torque all fasteners to specification
    Beginning with the forward flange bolts, torque all connections to specification using a calibrated torque wrench. Torque flange bolts in a cross-pattern to ensure even seating. Torque exhaust clamps evenly. If hanger bolts were removed, torque to specification.
    Torque spec

    Flange Bolts45 Nm (33 lb-ft)

    Exhaust Clamps55 Nm (41 lb-ft)

    Hanger Bolts27 Nm (20 lb-ft)
12. 12

    Final inspection
    Perform a final visual inspection of all connections, verifying proper torque, gasket seating, and clearances. Check that all rubber hangers are properly seated and not damaged. Verify no tools or parts were left in the work area.

Reassembly

1. Lower vehicle from jack stands carefully
2. Remove wheel chocks
3. Start engine and allow to idle, listening for exhaust leaks at connections
4. Perform a brief test drive, then re-inspect all connections for leaks or looseness after exhaust system reaches operating temperature

Verification

• Start engine and listen for exhaust leaks at all connection points - there should be no hissing or ticking sounds
• Visually inspect all connections while engine is running for visible exhaust gas escape
• Verify resonator is not contacting chassis, driveshaft, or suspension components during idle
• Test drive vehicle and verify no abnormal exhaust noise, vibration, or rattling
• After test drive, re-check all torque specifications and inspect for any signs of exhaust leaks
• Verify exhaust note sounds normal for S65 AMG (should be deep and smooth without raspiness or drone)

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