GM S-Series Pick-ups and SUV's 1994-1999 Repair Guide

Engine

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REMOVAL & INSTALLATION



See Figure 1

In the process of removing the engine, you will come across a number of steps which call for the removal of a separate component or system, such as "disconnect the exhaust system'' or "remove the radiator.'' In most instances, a detailed removal procedure can be found elsewhere in this guide.

It is virtually impossible to list each individual wire and hose which must be disconnected, simply because so many different model and engine combinations have been manufactured. Careful observation and common sense are the best possible approaches to any repair procedure.

Removal and installation of the engine can be made easier if you follow these basic points:



If you have to drain any of the fluids, use a suitable container.
 
Always tag any wires or hoses and, if possible, the components they came from before disconnecting them.
 
Because there are so many bolts and fasteners involved, store and label the retainers from components separately in muffin pans, jars or coffee cans. This will prevent confusion during installation.
 
After unbolting the transmission or transaxle, always make sure it is properly supported.
 
If it is necessary to disconnect the air conditioning system, have this service performed by a qualified technician using a recovery/recycling station. If the system does not have to be disconnected, unbolt the compressor and set it aside.
 
When unbolting the engine mounts, always make sure the engine is properly supported. When removing the engine, make sure that any lifting devices are properly attached to the engine. It is recommended that if your engine is supplied with lifting hooks, your lifting apparatus be attached to them.
 
Lift the engine from its compartment slowly, checking that no hoses, wires or other components are still connected.
 
After the engine is clear of the compartment, place it on an engine stand or workbench.
 
After the engine has been removed, you can perform a partial or full teardown of the engine using the
 



Click image to see an enlarged view

Fig. Fig. 1: When removing nuts, bolts and other parts, place them in a tray or similar container

4.3L Engines

See Figures 2, 3, 4 and 5



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Fig. Fig. 2: Unfasten the skid plate retaining bolts



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Fig. Fig. 3: Remove the skid plate from the vehicle



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Fig. Fig. 4: Remove the air cleaner assembly



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Fig. Fig. 5: Relieve the belt tension, then remove the serpentine belt

  1. Disconnect the negative battery cable and properly relieve the fuel system pressure.
  2.  
  3. Disconnect the vacuum reservoir and/or the underhood light from the hood (as equipped), then remove the outer cowl vent grilles.
  4.  
  5. Matchmark and remove the hood from the vehicle.
  6.  
  7. Raise and support the front of the vehicle safely using jackstands. It will be most convenient if the truck can be supported so underhood access is still possible. Otherwise, the truck will have to be raised and lowered multiple times during the procedure for the necessary access.
  8.  
  9. Drain the engine cooling system and the engine oil into separate drain pans.
  10.  
  11. Disconnect the oxygen sensor and/or wiring.
  12.  
  13. Disconnect the exhaust at the manifolds and loosen the hanger at the catalytic converter. This is necessary to remove the rear catalytic converter cushion mounts for removal of the exhaust assembly.
  14.  
  15. If equipped, remove the skid plate.
  16.  
  17. Remove the pencil braces from the engine to the transmission.
  18.  
  19. If equipped, remove the slave cylinder and position aside.
  20.  
  21. Disconnect the line clamp at the bellhousing.
  22.  
  23. Tag and disconnect the wiring from the starter, remove the flywheel cover and remove the starter from the vehicle.
  24.  
  25. On some 1998-99 4WD models, remove the transfer case.
  26.  
  27. Remove the oil filter.
  28.  
  29. Remove the engine mount through-bolts.
  30.  
  31. Remove the rear engine mount crossbar nut and washer.
  32.  
  33. Unfasten all of the bellhousing bolts, except the upper left bolt.
  34.  
  35. Disconnect the battery ground (negative) cable from the engine.
  36.  
  37. On 4WD vehicles, remove the front drive axle bolts and roll the axle downward.
  38.  
  39. Remove the air cleaner assembly and duct work.
  40.  
  41. Remove the upper radiator shroud, then remove the fan assembly.
  42.  
  43. Remove the multi-ribbed serpentine drive belt, then remove the water pump pulley.
  44.  
  45. Disconnect the upper radiator hose, then remove the A/C compressor (if equipped) and position aside with the lines intact.
  46.  
  47. Disconnect the lower radiator hose, then disconnect the oil cooler and overflow lines from the radiator. Plug the cooler line openings to prevent system contamination or excessive fluid loss.
  48.  
  49. Remove the radiator from the vehicle, then remove the lower radiator shroud.
  50.  
  51. Disconnect the power steering hoses from the steering gear, then cap the openings to prevent system contamination or excessive fluid loss.
  52.  
  53. Disconnect the heater hoses from the intake manifold and the water pump.
  54.  
  55. Tag, disconnect and remove the wiring harness and vacuum lines from the engine. On some later model vehicles, remove the distributor assembly from the engine.
  56.  
  57. Disconnect the throttle cables, then remove the distributor cap.
  58.  
  59. Support the transmission with a jack and remove the remaining bolt from the bellhousing.
  60.  
  61. Disconnect the fuel lines and remove the bracket.
  62.  
  63. Remove the ground strap(s) from the rear of the cylinder head.
  64.  
  65. On 4WD vehicles, loosen the front body mount bolts.
  66.  
  67. Support the transmission using a jack.
  68.  
  69. Install a suitable lifting device and carefully lift the engine from the vehicle. Pause several times while lifting the engine to make sure no wires or hoses have become snagged.
  70.  

To install:
  1. Carefully lower the engine into the vehicle.
  2.  
  3. On 4WD vehicles, tighten the front body mount bolts.
  4.  
  5. Install the ground strap(s) to the rear of the cylinder head.
  6.  
  7. Connect the fuel lines and install the bracket.
  8.  
  9. Install the upper left bellhousing bolt and remove the jack supporting the transmission.
  10.  
  11. If removed, install the distributor, then install the distributor cap and wires.
  12.  
  13. Connect the throttle cables.
  14.  
  15. Attach the vacuum lines and wiring harness connectors as noted during removal.
  16.  
  17. Attach the heater hoses, then uncap and connect the power steering hoses.
  18.  
  19. Install the lower shroud, then install the radiator.
  20.  
  21. Uncap and attach the oil cooler lines to the radiator, then connect the overflow hose.
  22.  
  23. Connect the lower radiator hose, then if equipped, reposition and secure the A/C compressor to the engine.
  24.  
  25. Attach the upper radiator hose, then install the water pump pulley.
  26.  
  27. Install the serpentine drive belt, then install the fan assembly.
  28.  
  29. Install the upper radiator shroud.
  30.  
  31. Install the air cleaner and ducts.
  32.  
  33. For 4WD vehicles, roll the front axle up into position, then install and tighten the retaining bolts.
  34.  
  35. Connect the battery ground strap to the engine block.
  36.  
  37. Install the remaining bellhousing bolts.
  38.  
  39. Install the engine mount through-bolts and tighten to 49 ft. lbs. (66 Nm).
  40.  
  41. Install the rear engine mount crossbar nut and washer. Tighten the nut to 33 ft. lbs. (45 Nm).
  42.  
  43. If removed on some 1998-99 4WD models, install the transfer case.
  44.  
  45. Install a new oil filter.
  46.  
  47. Install the starter motor.
  48.  
  49. Install the line clamp at the bellhousing.
  50.  
  51. Install the flywheel cover.
  52.  
  53. If equipped, reposition and secure the clutch slave cylinder.
  54.  
  55. Install the pencil brace and the skid plate, as equipped.
  56.  
  57. Install the catalytic converter Y-pipe assembly and hangers.
  58.  
  59. Remove the jackstands and carefully lower the truck.
  60.  
  61. Align the marks made during removal and install the hood.
  62.  
  63. Install the outer cowl vent grilles, then connect the vacuum reservoir and/or the underhood light to the hood (as equipped).
  64.  
  65. Check all powertrain fluid levels and add, as necessary. Be sure to properly fill the engine crankcase with clean engine oil.
  66.  
  67. Connect the negative battery cable and properly fill the engine cooling system.
  68.  
  69. Start and run the engine, then check for leaks.
  70.  

2.2L (VIN 4) Engines

CAUTION
Never open, service or drain the radiator or cooling system when hot; serious burns can occur from the steam and hot coolant. Also, when draining engine coolant, keep in mind that cats and dogs are attracted to ethylene glycol antifreeze and could drink any that is left in an uncovered container or in puddles on the ground. This will prove fatal in sufficient quantities. Always drain coolant into a sealable container. Coolant should be reused unless it is contaminated or is several years old.

In certain cases on some models the A/C system will have to be evacuated because the compressor may need to be removed from the vehicle to allow clearance for engine removal. On other models you maybe able to set the compressor and lines to one side and still have enough clearance to remove the engine. In this case the system does not have to be evacuated because the lines do not have to be disconnected from the compressor. To check if your system has to be evacuated, unplug the electrical connectors from the compressor, then unbolt the compressor assembly. Unfasten any brackets holding the refrigerant lines and try to set the components aside so that you will have enough clearance for engine removal. If there is not enough clearance for engine removal you must have the refrigerant recovered from the A/C system by a facility equipped with an approved recovery station before attempting to remove the engine from your vehicle. DO NOT attempt this without the proper equipment. R-134a should NOT be mixed with R-12 refrigerant and, depending on your local laws, attempting to service this system could be illegal.

  1. Disconnect the negative battery cable and properly relieve the fuel system pressure.
  2.  
  3. Drain the engine cooling system and the engine oil into separate drain pans.
  4.  
  5. Matchmark and remove the hood from the vehicle.
  6.  
  7. On 1997 models, remove the battery.
  8.  
  9. Raise and support the front of the vehicle safely using jackstands. It will be most convenient if the truck can be supported so underhood access is still possible. Otherwise, the truck will have to be raised and lowered multiple times during the procedure for the necessary access.
  10.  
  11. Unplug the Oxygen sensor electrical connection.
  12.  
  13. Disconnect the exhaust pipe from the manifold. On some models it may also be necessary to disconnect the catalytic converter from the exhaust pipe.
  14.  
  15. Remove the braces from the engine and the transmission (if equipped).
  16.  
  17. On 1998-99 models, remove the starter motor.
  18.  
  19. Unbolt the transmission and separate it from the engine or, if necessary, remove it from the vehicle.
  20.  
  21. If necessary for clearance on 1998-99 models, remove the alternator rear brace by unfastening the bolt and nuts.
  22.  
  23. Disconnect the ground straps from the engine block and remove the drive belt.
  24.  
  25. On 1997 models, GM recommends that you remove the water pump. We have removed quite a few of these engines and as of yet, we still have not had to remove the water pump when removing the engine. However, if you feel that there is not enough clearance to remove the engine without causing damage, then by all means remove the pump. It is always better to be careful so that you won't have to buy any unnecessary replacement parts, because we all know how expensive they can be.
  26.  
  27. Remove the A/C compressor and bracket. If possible, set the compressor and bracket to one side without disconnecting the lines.
  28.  
  29. Tag and disconnect the hoses and transmission coolant lines engaged to the radiator, then remove the radiator.
  30.  
  31. Remove the power steering pump and cap the power steering lines to avoid contamination.
  32.  
  33. Tag and disengage the heater hoses from the heater core in the bulkhead or from the manifold.
  34.  
  35. Disconnect the 12 volt supply from the mega fuse, if necessary.
  36.  
  37. Tag and unplug all electrical connections and wiring harnesses.
  38.  
  39. Tag and unplug all vacuum lines.
  40.  
  41. Disengage the throttle cable, and if equipped the cruise control cable.
  42.  
  43. If necessary for clearance on 1998-99 models, remove the EGR pipe and the EGR valve.
  44.  
  45. Disconnect the fuel lines.
  46.  
  47. Install a suitable lifting device to the engine.
  48.  
  49. Remove the engine mount bolts and carefully lift the engine from the vehicle. Pause several times while lifting the engine to make sure no wires or hoses have become snagged.
  50.  

To install:
  1. Carefully lower the engine into the vehicle and install the engine mount bolts. Remove the engine lifting device.
  2.  
  3. Connect the fuel lines.
  4.  
  5. If removed, connect the 12 volt supply to the mega fuse.
  6.  
  7. Attach all vacuum lines, electrical connections and wiring harnesses that were tagged and disconnected during the removal process.
  8.  
  9. If removed for clearance on 1998-99 models, install the EGR valve and pipe.
  10.  
  11. Connect the throttle and if equipped, the cruise control cable.
  12.  
  13. Connect the heater hoses to the heater core in the bulkhead or to the manifold.
  14.  
  15. Install the power steering pump and attach the lines.
  16.  
  17. Install the A/C compressor.
  18.  
  19. Install the radiator and attach all hoses and fluid cooler lines.
  20.  
  21. If removed for clearance on 1997 models, install the water pump.
  22.  
  23. Install the drive belt.
  24.  
  25. Connect the ground strap to the engine.
  26.  
  27. If removed for clearance on 1998-99 models, install the alternator rear brace and tighten the bolt and nuts.
  28.  
  29. Engage the transmission to the engine.
  30.  
  31. On 1998-99 models, install the starter motor.
  32.  
  33. Install the braces to the engine and the transmission (if equipped).
  34.  
  35. Connect the exhaust pipe to the manifold. If removed connect the catalytic converter to the exhaust pipe.
  36.  
  37. Attach the oxygen sensor electrical connection.
  38.  
  39. Remove the jackstands and carefully lower the truck.
  40.  
  41. Install the battery.
  42.  
  43. Align the marks made during removal and install the hood.
  44.  
  45. Check all powertrain fluid levels and add, as necessary. Be sure to properly fill the engine crankcase with clean engine oil.
  46.  
  47. Connect the battery cables and properly fill the engine cooling system.
  48.  
  49. Start and run the engine, then check for leaks.
  50.  

 
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