GM Service Manual Online
For 1990-2009 cars only

Compressor Pressure Relief Valve Replacement 7.4L

Removal Procedure

    Caution: Unless directed otherwise, the ignition and start switch must be in the OFF or LOCK position, and all electrical loads must be OFF before servicing any electrical component. Disconnect the negative battery cable to prevent an electrical spark should a tool or equipment come in contact with an exposed electrical terminal. Failure to follow these precautions may result in personal injury and/or damage to the vehicle or its components.

  1. Disconnect the negative battery cable.
  2. Disconnect the electrical connectors, as necessary.

  3. Object Number: 257977  Size: SH
  4. Remove the compressor pressure relief valve.
  5. Remove the O-ring seal.

Installation Procedure

  1. Coat the O-ring seal with 525 viscosity refrigerant oil.

  2. Object Number: 257977  Size: SH
  3. Install the new O-ring seal.
  4. 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.

  5. Install the compressor pressure relief valve.
  6. Tighten
    Tighten the compressor pressure relief valve to 6 N·m (53 lb in).

  7. Connect the electrical connectors, as necessary.
  8. Connect the negative battery cable.

Compressor Pressure Relief Valve Replacement All Except 7.4L

Removal Procedure

    Caution: Unless directed otherwise, the ignition and start switch must be in the OFF or LOCK position, and all electrical loads must be OFF before servicing any electrical component. Disconnect the negative battery cable to prevent an electrical spark should a tool or equipment come in contact with an exposed electrical terminal. Failure to follow these precautions may result in personal injury and/or damage to the vehicle or its components.

  1. Disconnect the negative battery cable.
  2. Disconnect the electrical connectors, as necessary.

  3. Object Number: 257978  Size: SH
  4. Remove the compressor pressure relief valve.
  5. Remove the O-ring seal.

Installation Procedure

  1. Coat the O-ring seal with 525 viscosity refrigerant oil.

  2. Object Number: 257978  Size: SH
  3. Install the new O-ring seal.
  4. 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.

  5. Install the compressor pressure relief valve.
  6. Tighten
    Tighten the compressor pressure relief valve to 6 N·m (53 lb in).

  7. Connect the electrical connectors, as necessary.
  8. Connect the negative battery cable.