GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 GMC_Truck 🢒 1998 🢒 GMC P42 Commercial Chassis 🢒 General Information 🢒 General Information 🢒 Engine Mount Replacement

Removal Procedure
  1. Inspect the engine mounts. Refer to Engine Mount Inspection .
  2. Raise the vehicle. Refer to Lifting and Jacking the Vehicle in General Information.

    3. Object Number: 66191 Size: SH
  3. Remove the through bolt and the nut from the front engine mount that is being replaced.

    4. Object Number: 374320 Size: SH

    Notice: When raising or supporting the engine for any reason, do not use a jack under the oil pan, any sheet metal, or the crankshaft pulley. Due to the small clearance between the oil pan and the oil pump screen, jacking against the oil pan may cause the pan to be bent against the pump screen. This will result in a damaged oil pickup unit.

  4. Using a jack on the square tab (left side shown) at the rear of the engine block, raise the engine. Remove the starter in order to access the square tab on the right side. Refer to Starter Motor Replacement In Engine Electrical.
  5. Raise the front of the engine only enough to permit removal of the engine mount.

    6. Object Number: 68945 Size: SH
  6. Remove the bolts from the front engine mount bracket.
  7. Remove the front engine mount bracket.
  8. Remove the nuts and the bolts from the front engine mount.
  9. Remove the front engine mount assembly.

Installation Procedure

    Object Number: 68945 Size: SH
  1. Install the front engine mount assembly to the mount bracket.

    2. Notice: Use the correct fastener in the correct location. Replacement fasteners must be the correct part number for that application. Fasteners requiring replacement or fasteners requiring the use of thread locking compound or sealant are identified in the service procedure. Do not use paints, lubricants, or corrosion inhibitors on fasteners or fastener joint surfaces unless specified. These coatings affect fastener torque and joint clamping force and may damage the fastener. Use the correct tightening sequence and specifications when installing fasteners in order to avoid damage to parts and systems.

  2. Install the nuts and the bolts.

    3. Tighten
    Tighten the bolts to 41 N·m (30 lb ft).


    Object Number: 66191 Size: SH
  3. Install the front engine mount bracket to the engine block.

    4. Tighten
    Tighten the bolts to 47 N·m (35 lb ft).

  4. Lower the engine until the through bolt can be inserted.
  5. Install the engine mount through bolt and nut.

    6. Tighten
    Tighten the nut to 56 N·m (41 lb ft).

  6. Remove the engine support.
  7. Lower the vehicle.