Chevrolet Blazer/Jimmy 1969-1982 Repair Guide

Timing Chain/Gear Cover

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REMOVAL & INSTALLATION



Six Cylinder Engines


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Fig. Fig. 1 On 1973-82 6 cylinder models, modify the oil pan front seal as illustrated



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Fig. Fig. 2 Apply sealer to the points indicated-6 cylinder engines

  1. Drain the oil and remove the oil pan on 1969-72 models.
  2.  
  3. Remove the radiator after draining it.
  4.  


CAUTION
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 quantity. Always drain coolant into a sealable container. Coolant should be reused unless it is contaminated or is several years old.

  1. Remove the fan, pulley, and belt. Remove any power steering and/or AIR pump drive belts. Remove any braces for the above pumps which will interfere with cover removal and position the pumps out of the way.
  2.  
  3. Remove the crankshaft pulley and damper. Use a puller to remove the damper. Do not attempt to pry or hammer the damper off, for it will be damaged.
  4.  
  5. On 1969-72 models unfasten the retaining bolts, and remove the cover.
  6.  
  7. Remove the two oil pan-to-front cover attaching screws.
  8.  
  9. Remove the front cover-to-block attaching screws.
  10.  
  11. On 1973 and later models, pull the cover forward slightly and cut the oil pan front seal off flush with the block. Remove the cover. On installation, cut the tabs off a new oil pan front seal and install it to the cover.
  12.  
  13. On installation, coat the gasket with sealer and use a 1 / 8 inch bead of silicone sealer at the oil pan to cylinder block joint. Replace the damper before tightening the cover bolts down, so that the cover seal will align. The damper must be drawn into place; it may be broken by hammering.
  14.  
  15. Replace the oil pan if it was removed.
  16.  

V8 Engines


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Fig. Fig. 3 When removing the timing cover, it may be helpful remove the radiator ...



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Fig. Fig. 4 ... then remove the cooling fan retainers and fan



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Fig. Fig. 5 Remove the water pump bolts and the water pump



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Fig. Fig. 6 Remove the crankshaft pulley bolts



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Fig. Fig. 7 Unfasten the crankshaft damper retaining bolt ...



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Fig. Fig. 8 ... then remove the bolt



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Fig. Fig. 9 Place a puller on the crankshaft damper ...



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Fig. Fig. 10 ... then remove the damper from the crankshaft



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Fig. Fig. 11 Unfasten the timing cover retaining bolts ...



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Fig. Fig. 12 ... then remove the timing cover



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Fig. Fig. 13 Applying sealer to the oil pan lip-V8 engines

  1. Drain the oil and remove the oil pan. The pan need not be removed on 1975 and later engines.
  2.  
  3. Drain and remove the radiator.
  4.  
  5. Remove the fan, pulley, and belt. Remove any power steering and/or AIR pump drive belts. Remove any braces for these pumps which will interfere with cover removal and position the pumps out of the way.
  6.  
  7. Remove the water pump.
  8.  
  9. Remove the crankshaft pulley, the damper retaining bolt and damper. Use a puller on the damper. Do not attempt to pry or hammer the damper off.
  10.  
  11. Remove the retaining bolts, and remove the timing cover.
  12.  
  13. To install the cover on 1969-74 models:
  14.  
    1. Coat the crankshaft oil seal with engine oil.
    2.  
    3. Coat the new gasket with sealer. Install the cover and gasket. Replace the damper before tightening the cover bolts down, so that the cover seal will align. The damper must be drawn into place; it may be broken by hammering.
    4.  
    5. Replace the oil pan and water pump.
    6.  

  15. To install the cover on 1975-82 models:
  16.  
    1. Clean the gasket mating surfaces.
    2.  
    3. Remove any oil pan gasket material that may still be adhering to the oil pan-engine block joint face.
    4.  
    5. Apply a 1 / 8 inch bead of silicone sealer to the joint formed by the oil pan and cylinder block, as well as to the entire oil pan front lip.
    6.  
    7. Coat the cover gasket with gasket sealer and place it in position on the front cover.
    8.  
    9. Loosely install the front cover on the block. Install the 4 top bolts loosely (about 3 turns). Install two 1 / 4 -20X 1 / 2 inch screws in the hole at each side of the front cover and apply a bead of sealant on the bottom of the seal and install it on the cover.
    10.  
    11. Tighten the screws evenly while aligning the dowel pins and holes in the front cover.
    12.  
    13. Remove the 1 / 4 -20X 1 / 2 inch screws and install the rest of the cover screws.
    14.  
    15. Further installation is the reverse of removal. Refill the engine with oil.
    16.  


Diesel Engines

CAUTION
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 quantity. Always drain coolant into a sealable container. Coolant should be reused unless it is contaminated or is several years old.

  1. Drain the cooling system and remove the water pump.
  2.  
  3. Rotate the engine until the marks on the pump gear and the camshaft gear align.
  4.  
  5. Scribe a mark aligning the injection pump flange and the front cover.
  6.  
  7. Remove the crankshaft pulley and the torsional damper.
  8.  
  9. Remove the 4 front cover-to-oil pan bolts.
  10.  
  11. Remove the fuel return line clips.
  12.  
  13. Remove the injection pump driven gear and then remove the injection pump retaining bolts from the front cover.
  14.  
  15. Remove the baffle. Remove the remaining front cover bolts and remove the front cover.
  16.  

To install:

  1. Clean all sealing surfaces and place a 1 / 18 inch bead of sealant as shown in the illustration. Apply RTV sealer to the bottom portion of the front cover where it attaches to the oil pan.
  2.  
  3. Install the front cover and then install the baffle.
  4.  
  5. Install the injection pump making sure the scribe marks on the pump and the front cover align.
  6.  
  7. Install the injection pump driven gear making sure that the marks on the pump gear and the cam gear align.
  8.  
  9. Installation of the remaining components is in the reverse order.
  10.  

 
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