Engine Mount - Front

Replace the front engine mount on a 2019 Mercedes-Benz G-Class with 4.0L Turbo V8 engine, including support of engine weight, removal of mount hardware, and installation with proper torque specifications.

Warnings

Tools required

Parts

• Front engine mount assembly × 1 — Use OEM specification

Preparation

1. Park vehicle on level surface and engage parking brake.
2. Allow engine to cool completely if vehicle has been recently operated.
3. Disconnect negative battery terminal to prevent accidental starter engagement.
4. Raise front of vehicle using floor jack and support securely on jack stands at manufacturer-specified lift points.
5. Remove front skid plate or undertray if equipped to access engine mount from below.

Procedure

1. 1

   Install engine support system
   Position engine support fixture across engine bay or place transmission jack with engine support adapter under oil pan (use a block of wood to distribute load). Raise support slightly to contact engine but do not lift yet. Engine will need controlled support during mount removal.
2. 2

   Locate front engine mount
   From below vehicle, identify the front engine mount assembly. The mount connects the engine block to the front crossmember/subframe. Note the position of the mount bracket, through-bolt orientation, and any alignment marks or indexing features for reinstallation reference.
3. 3

   Disconnect mount accessories
   Disconnect any electrical connectors attached to the mount assembly if equipped with active/hydraulic mount technology. The front engine mounts on the M176 G-Class are conventional (non-hydraulic) rubber mounts with no electrical connectors. Check for any wiring harnesses, coolant, or vacuum lines routed near the mount that may require temporary repositioning for access. On M176 engine, verify no wiring harnesses are trapped under mount bracket.
4. 4

   Remove through-bolt
   Locate the large through-bolt that passes horizontally through the center of the mount assembly, connecting the upper and lower mount sections. Apply penetrating lubricant if fastener shows corrosion. Use appropriate E-Torx or Torx socket to remove the through-bolt completely and set aside.
   Torque spec

   Engine Mount Through-Bolt85 Nm (63 lb-ft)
5. 5

   Support engine weight
   Using the engine support fixture or transmission jack, carefully raise the engine approximately 5-10mm to unload the front mount. Raise slowly and watch for any contact with hood, firewall, or surrounding components. Engine should be just high enough to relieve weight from mount without stressing hoses, wiring, or other components.
6. 6

   Remove upper mount-to-block fasteners
   Remove the bolts securing the upper mount bracket to the engine block. These are typically E-Torx fasteners located on the side of the engine block where the mount bracket attaches. Remove all fasteners and retain for comparison with new mount hardware.
   Torque spec

   Engine Mount-to-Block Bolts65 Nm (48 lb-ft)
7. 7

   Remove lower mount-to-frame fasteners
   From below, remove the bolts securing the lower mount bracket to the front crossmember or subframe. These fasteners pass upward through the subframe into the mount bracket. Support the mount assembly as you remove the final fastener.
   Torque spec

   Engine Mount-to-Frame Bolts75 Nm (55 lb-ft)
8. 8

   Remove front engine mount assembly
   With all fasteners removed, carefully extract the front engine mount assembly from between the engine and subframe. May require slight repositioning of engine height or gentle prying to free mount from alignment pins or indexing features. Inspect removed mount for failure mode (rubber separation, fluid leakage, collapsed bushings).
9. 9

   Prepare mounting surfaces
   Clean all mounting surfaces on engine block and subframe where new mount will contact. Remove any corrosion, old gasket material, or debris. Inspect mounting bolt holes in engine block and subframe for thread damage. Verify alignment pins or locating features are intact and undamaged.
10. 10

    Position new front engine mount
    Guide new front engine mount assembly into position between engine block and subframe. Align any indexing pins or locating features. May require adjusting engine height slightly to align all mounting points simultaneously. Use pry bar or alignment tool if needed to position mount correctly.
11. 11

    Install lower mount-to-frame fasteners
    Install the lower mount bracket bolts through the subframe into the mount bracket. Start all fasteners by hand to ensure proper thread engagement. Torque to specification in a cross-pattern sequence.
    Torque spec

    Engine Mount-to-Frame Bolts75 Nm (55 lb-ft)
12. 12

    Install upper mount-to-block fasteners
    Install the upper mount bracket bolts into the engine block. Start all fasteners by hand to verify alignment and thread engagement. Torque to specification in a cross-pattern sequence.
    Torque spec

    Engine Mount-to-Block Bolts65 Nm (48 lb-ft)
13. 13

    Install through-bolt
    Insert the through-bolt through the center of the mount assembly, connecting the upper and lower mount sections. Ensure bolt passes cleanly through all mount components. Torque to specification.
    Torque spec

    Engine Mount Through-Bolt85 Nm (63 lb-ft)
14. 14

    Lower engine and remove support
    Carefully lower engine using support fixture or transmission jack until engine weight is fully transferred to new mount. Verify mount is properly seated and compressed. Remove engine support equipment from engine bay or under vehicle.
15. 15

    Reconnect mount accessories
    Reconnect any electrical connectors to active/hydraulic mount assembly if applicable. Verify wiring harnesses are properly routed and not pinched or in contact with hot exhaust components.
16. 16

    Reinstall underbody protection
    Reinstall front skid plate or undertray if removed during access. Verify all fasteners are secure. Lower vehicle from jack stands and reconnect negative battery terminal.

Reassembly

1. Torque all fasteners to specifications in the sequence described.
2. Verify engine sits level and all mounts are properly loaded before final verification.
3. Check clearance between engine and all surrounding components (hood, firewall, hoses, wiring).

Verification

• Start engine and verify it idles smoothly without excessive vibration or movement.
• With engine running, have assistant apply brake and shift through drive ranges (P-R-N-D) while observing engine movement. Excessive pitch or roll indicates mount not properly seated or additional mount failure.
• Turn engine off and visually inspect mount for proper compression and alignment.
• Test drive vehicle and verify no abnormal vibration at idle, during acceleration, or deceleration.
• Recheck all mount fastener torque after test drive.

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