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

Timing Chain Cover and Seal

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REMOVAL & INSTALLATION



2.2L Engine
1994-95 MODELS
  1. Disconnect the negative battery cable.
  2.  
  3. Remove the power steering fluid reservoir from the radiator shroud, then remove the upper fan shroud.
  4.  
  5. Carefully release the belt tension, then remove the serpentine drive belt.
  6.  
  7. Remove the alternator and brackets from the engine, then position them aside.
  8.  
  9. Remove the crankshaft pulley and hub. For details, please refer to the procedure located earlier in this section.
  10.  
  11. As necessary, disconnect the lower radiator hose clamp at the water pump, then loosen and/or remove the oil pan.
  12.  

There may be bolts attaching the front of the oil pan to the timing cover. If so, make sure they are removed before attempting to remove the cover.

  1. Unfasten the crankcase (timing) front cover bolts, then disengage cover from the engine. Make sure all bolts are removed and be careful not to force and damage the cover.
  2.  
  3. Carefully remove the old crankshaft seal from the cover using a suitable prytool. Be very careful not to distort the front cover or to score the end of the crankshaft.
  4.  

To install:
  1. Carefully remove all traces of gasket or sealant from the mating surfaces.
  2.  
  3. Lubricate the lips of a new seal with clean engine oil, then use a seal centering tool (such as J-35468 or equivalent) to install the seal to the front cover. Leave the tool in position in the seal until the cover is installed.
  4.  
  5. Apply a 3 / 8 in. (10mm) wide by 5 / 16 (5mm) thick bead of RTV sealer to the oil pan at the front crankcase cover sealing surface. Then apply a 1 / 4 in. (6mm) by 1 / 8 in. (3mm) thick bead of RTV to the crankcase front cover at the block sealing surface.
  6.  
  7. Install the crankcase front cover to the engine using the seal tool to assure it is properly centered and prevent damage to the hub. Tighten the cover retaining bolts to 97 inch lbs. (11 Nm), then remove the seal centering tool.
  8.  
  9. Install the lower radiator hose clamp at the water pump, then install and secure the oil pan, as applicable.
  10.  
  11. If removed, install the oil pan.
  12.  
  13. Install the crankshaft pulley and hub.
  14.  
  15. Reposition and secure the alternator with brackets.
  16.  
  17. Install the serpentine drive belt, then install the upper fan shroud.
  18.  
  19. Reposition and secure the power steering reservoir.
  20.  
  21. Connect the negative battery cable.
  22.  

1996-99 MODELS

See Figures 1 through 8

  1. Disconnect the negative battery cable.
  2.  
  3. Carefully release the belt tension, then remove the serpentine drive belt.
  4.  
  5. Remove the cooling fan assembly and pulley.
  6.  
  7. Remove the crankshaft pulley and hub.
  8.  
  9. Remove the belt tensioner/idler pulley assembly.
  10.  
  11. Remove the front oil pan-to-front cover nuts or studs.
  12.  
  13. Remove the starter.
  14.  
  15. If necessary, remove the alternator and brackets from the engine, then position them aside.
  16.  
  17. Loosen but do not remove the oil pan bolts.
  18.  
  19. Unfasten the crankcase (timing) front cover bolts, then remove cover from the engine. Make sure all bolts are removed and be careful not to force and damage the cover.
  20.  
  21. Carefully remove the old crankshaft seal from the cover using a suitable prytool. Be very careful not to distort the front cover or to score the end of the crankshaft.
  22.  



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Fig. Fig. 1: The belt tensioner assembly is attached to the engine by three bolts located on the side of the unit



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Fig. Fig. 2: Unfasten the three bolts and remove the tensioner assembly



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Fig. Fig. 3: Raise the vehicle, support it jackstands and remove the front two oil pan nuts



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Fig. Fig. 4: The front cover is attached to the engine with a number of small bolts



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Fig. Fig. 5: After unfastening the front cover bolts, remove the cover. You may have to gently pry between the cover and oil pan to break the seal to get the cover off



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Fig. Fig. 6: Location of the front cover retaining bolt holes and studs



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Fig. Fig. 7: Use a suitable puller to remove the oil seal



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Fig. Fig. 8: A sealer driver and a hammer can be used to install a new seal

To install:
  1. Carefully remove all traces of gasket or sealant from the mating surfaces.
  2.  
  3. Lubricate the lips of a new seal with clean engine oil, then use a seal centering tool (such as J-35468 or equivalent) to install the seal to the front cover. Leave the tool in position in the seal until the cover is installed.
  4.  
  5. Apply a 3 / 8 in. (10mm) wide by 5 / 16 (5mm) thick bead of RTV sealer to the oil pan at the front crankcase cover sealing surface. Then apply a 1 / 4 in. (6mm) by 1 / 8 in. (3mm) thick bead of RTV to the crankcase front cover at the block sealing surface.
  6.  
  7. Install the crankcase front cover to the engine using the seal tool to assure it is properly centered and prevent damage to the hub. Tighten the cover retaining bolts to 97 inch lbs. (11 Nm), then remove the seal centering tool.
  8.  
  9. Install and secure the oil pan, as applicable.
  10.  
  11. Install the starter.
  12.  
  13. If removed, reposition and secure the alternator with brackets.
  14.  
  15. Install the belt tensioner/idler pulley assembly.
  16.  
  17. Install the belt assembly.
  18.  
  19. Install the crankshaft pulley and hub.
  20.  
  21. Install the cooling fan assembly and pulley.
  22.  
  23. Connect the negative battery cable.
  24.  

4.3L Engine

See Figures 9, 10 and 11



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Fig. Fig. 9: Remove the timing cover retaining bolts



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Fig. Fig. 10: Remove the timing cover from the vehicle


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.

  1. Disconnect the negative battery cable and drain the engine cooling system.
  2.  
  3. Remove the crankshaft pulley and damper.
  4.  


WARNING
The outer ring (weight) of the torsional damper is bonded to the hub with rubber. The damper must be removed with a puller which acts on the inner hub only. Pulling on the outer portion of the damper will break the rubber bond or destroy the tuning of the unit.

  1. Remove the water pump assembly.
  2.  
  3. Loosen the oil pan.
  4.  
  5. If applicable, remove the crankshaft position sensor.
  6.  
  7. Remove the front cover bolts and, if equipped, the reinforcements, then remove the front cover from the engine.
  8.  
  9. Pry the seal out of the front cover using a small prytool. Be very careful not to distort the front cover or to score the end of the crankshaft.
  10.  

To install:

On 1995-99 models, anytime the front cover is removed, the cover must be replaced upon reassembly. If you reuse the old cover, oil leaks may develop.

  1. Clean the gasket mating surfaces of the engine and cover of all remaining gasket or sealer material. Be careful not to score or damage the surfaces.
  2.  

The manufacturer suggests you wait until the front cover is mounted to the engine before you install the replacement crankshaft oil seal. This assures the cover is properly supported.

  1. Position a new front cover gasket to the engine or cover using gasket cement to hold it in position. Lubricate the front of the oil pan seal with engine oil to aid in reassembly.
  2.  
  3. Install the front cover to the engine. Take care while engaging the front of the oil pan seal with the bottom of the cover. On 1998-99 models, apply sealer 12346141, or an equivalent sealant to the oil pan rail where it contacts the timing cover-to-block joint (front) and the crankshaft rear seal retainer-to-block joint (rear). Continue the bead of sealant about 1 in. (25mm) in both directions from each of the four corners.
  4.  
  5. Install front cover retaining bolts and tighten to 124 inch lbs. (14 Nm) on 1994-95 models and 106 inch. lbs. (12 Nm) on 1996-99 models.
  6.  
  7. Lightly coat the lips of the replacement crankshaft seal with clean engine oil, then position the seal with the open end facing inward the engine. Use a suitable seal installation driver to position the seal in the front cover.
  8.  
  9. If removed, install a new crankshaft position sensor O-ring, then install the sensor.
  10.  
  11. Secure the oil pan.
  12.  
  13. Install the water pump.
  14.  
  15. Install the crankshaft damper and pulley.
  16.  
  17. Connect the negative battery cable, then properly refill the engine cooling system.
  18.  
  19. Run the engine until normal operating temperature has been reached, then check for leaks.
  20.  



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Fig. Fig. 11: Installing the crankshaft front oil seal-4.3L engines

 
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