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GM Buick/Oldsmobile/Pontiac/Full-Size 1975-1990 Repair Guide

Timing Chain Cover and Seal

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REMOVAL & INSTALLATION



See Figures 1, 2, 3, 4, 5, 6, 7, 8 and 9

Buick Built Engines
  1. Disconnect the negative battery cable. Drain the cooling system.
  2.  


CAUTION
When draining the coolant, keep in mind that cats and dogs are attracted by the ethylene glycol antifreeze, and are quite likely to drink any that is left in an uncovered container or in puddles on the ground. This will prove fatal in sufficient quantity. Always drain the coolant into a sealable container. Coolant should be reused unless it is contaminated or several years old.

  1. Remove the radiator, fan, pulley and belt.
  2.  
  3. Remove the fuel pump and alternator, if necessary to remove cover.
  4.  
  5. Remove the distributor. If the timing chain and sprockets will not be disturbed, note the position of the distributor for installation in the same position.
  6.  
  7. Remove the thermostat bypass hose.
  8.  
  9. Remove the harmonic balancer.
  10.  
  11. Remove the timing chain-to-crankcase bolts.
  12.  
  13. Remove the oil pan-to-timing chain cover bolts and remove the timing chain cover.
  14.  
  15. Using a punch, drive out the old seal and the shedder toward the rear of the seal.
  16.  

To install:
  1. Coil the new packing around the opening so the ends are at the top. Drive in the shedder using a punch. Stake it in place at three locations. Properly size the packing by rotating a hammer handle around the packing until the balancer hub can be inserted through the opening. Before beginning reassembly, remove the oil pump cover and pack the entire oil pump cavity tightly with petroleum grease. If this is not done, the oil pump cannot prime itself and the engine will be damaged. Coat the cover bolts with sealer.
  2.  
  3. Install the oil pan-to-timing chain cover and bolts.
  4.  
  5. Install the timing chain-to-crankcase bolts and torque to 35 ft. lbs. (48 Nm).
  6.  
  7. Install the harmonic balancer using balancer installer tool.
  8.  
  9. Install the thermostat bypass hose.
  10.  
  11. Install the distributor to the same position as removed.
  12.  
  13. Install the fuel pump and alternator.
  14.  
  15. Install the radiator, fan, pulley and belt.
  16.  
  17. Connect the negative battery cable. Refill the cooling system.
  18.  



Click image to see an enlarged view

Fig. Fig. 1: Engine front cover assembly; all models similar

Pontiac Built Engines
  1. Disconnect the negative battery cable. Drain the radiator and the cylinder block.
  2.  


CAUTION
When draining the coolant, keep in mind that cats and dogs are attracted by the ethylene glycol antifreeze, and are quite likely to drink any that is left in an uncovered container or in puddles on the ground. This will prove fatal in sufficient quantity. Always drain the coolant into a sealable container. Coolant should be reused unless it is contaminated or several years old.

  1. Loosen the alternator adjusting bolts.
  2.  
  3. Remove the fan, fan pulley, accessory drive belts, and water pump.
  4.  
  5. Disconnect the radiator hoses.
  6.  
  7. Remove the fuel pump.
  8.  
  9. Remove the harmonic balancer bolt and washer.
  10.  
  11. Remove harmonic balancer.
  12.  

Do not pry on rubber mounted balancers. If only the seal is to be replaced, proceed to Step 12.

  1. Remove the front four oil pan to timing cover bolts.
  2.  
  3. Remove the timing cover bolts and nuts and cover to intake manifold bolt.
  4.  
  5. Pull the cover forward and remove.
  6.  
  7. Remove the O-ring from the recess in the intake manifold.
  8.  

To install:
  1. Clean all the gasket surfaces.
  2.  
  3. To replace the seal, pry it out of the cover using a prybar. Install the new seal with the lip inward.
  4.  

The seal can be replaced with the cover installed.

  1. Making sure all gaskets are replaced. Torque the four oil pan bolts to 12 ft. lbs. (16 Nm), and the fan pulley bolts to 20 ft. lbs. (27 Nm).
  2.  
  3. Install harmonic balancer and torque the bolt to specifications.
  4.  
  5. Install the fuel pump.
  6.  
  7. Connect the radiator hoses.
  8.  
  9. Install the water pump, fan, pulley, accessory drive belts.
  10.  
  11. Tighten the alternator adjusting bolts.
  12.  
  13. Connect the negative battery cable. Refill the radiator and the cylinder block.
  14.  

Oldsmobile Built Gasoline Engines
  1. Disconnect the negative battery cable. Drain the coolant. Disconnect the radiator hose and the bypass hose. Remove the fan, belts and pulley.
  2.  


CAUTION
When draining the coolant, keep in mind that cats and dogs are attracted by the ethylene glycol antifreeze, and are quite likely to drink any that is left in an uncovered container or in puddles on the ground. This will prove fatal in sufficient quantity. Always drain the coolant into a sealable container. Coolant should be reused unless it is contaminated or several years old.

  1. Remove the vibration damper and crankshaft pulley.
  2.  
  3. On 1975-76 models only (which have no dowel pins), remove the oil pan.
  4.  
  5. Remove the front cover attaching bolts and remove the cover, timing indicator and water pump from the front of the engine. This requires removing all the bolts (four) that hold the cover on at the bottom, and four larger water pump mounting bolts that go right through the cover into the block. The two top center water pump mounting bolts and the two bottom such bolts remain in place and retain the water pump and gasket to the front of the cover. The other four water pump mounting bolts are removed. On 1977 and later models, remove the two dowel pins from the block. You may have to grind a flat on each pin to get a good grip.
  6.  
  7. On 1977 and later models, grind a chamfer on the end of each dowel pin as illustrated. When installing the dowel pins, they must be inserted chamfered end first. Trim about 1 / 8 in. (3.1mm) from each end of the new front pan seal and trim any excess material from the front edge of the oil pan gasket. Be sure all mating surfaces are clean.
  8.  
  9. On 1975-76 models apply a sealer around water holes on the new cover gasket before applying it to the block.
  10.  
  11. On 1977 and later models:
    1. Clean all seal mating surfaces with solvent.
    2.  
    3. When installing the new front cover gasket, first apply sealer to the water pump bolt hole areas of the seal and then position the gasket to the block.
    4.  
    5. Apply RTV sealer to the junction of block, pan, and front cover.
    6.  
    7. In positioning the front cover onto the block and gasket, press it downward to compress the seal. Then, rotate the cover left and right while you guide the pan seal into the cavity with a small prybar, as shown. Now, apply oil to the threads and install two of the bolts finger tight to hold the cover in place. Install the two dowel pins, chamfered end first.
    8.  

  12.  
  13. To install, note these points:
    1. When installing cover bolts, first coat them with engine oil. Tighten evenly, torquing the four lower bolts to 35 ft. lbs. (48 Nm) and the four bolts passing through the water pump to 22 ft. lbs. (30 Nm).
    2.  
    3. Apply a high quality lubricant (an example is GM 1050169) to the sealing surface of the balancer.
    4.  
    5. When installing the balancer bolt, torque to proper specifications. Crankshaft pulley attaching bolts are torqued to 10 ft. lbs. (14 Nm); fan pulley attaching bolts are torqued to 20 ft. lbs. (27 Nm).

      Click image to see an enlarged view

      Fig. Fig. 2: RTV sealer application



      Click image to see an enlarged view

      Fig. Fig. 3: Guiding the front cover in place



      Click image to see an enlarged view

      Fig. Fig. 4: Chamfer on the dowel pins

    6.  

  14.  

Chevrolet Built Engines
  1. Disconnect the negative battery cable. Drain the cooling system.
  2.  


CAUTION
When draining the coolant, keep in mind that cats and dogs are attracted by the ethylene glycol antifreeze, and are quite likely to drink any that is left in an uncovered container or in puddles on the ground. This will prove fatal in sufficient quantity. Always drain the coolant into a sealable container. Coolant should be reused unless it is contaminated or several years old.

  1. Remove the crankshaft pulley with a puller. Remove the water pump. Remove the screws holding the timing case cover to the block and remove the cover and gaskets.
  2.  
  3. Use a suitable tool to pry the old seal out of the front face of the cover.
  4.  

To install:
  1. Install the new seal so that open end is toward the inside of the cover.
  2.  

Coat the lip of the new seal with oil prior to installation.

  1. Check that the timing chain oil slinger is in place against the crankshaft sprocket.
  2.  
  3. Apply a 1 / 8 in. (3.1mm) bead of RTV sealer to the joint formed by the oil pan and cylinder block.
  4.  
  5. Coat the cover gasket with sealer and position it on the block. Coat the bottom of the crankshaft seal with engine oil and carefully position the cover over the crankshaft and onto the locating dowels. Make sure you don't force the cover over the dowels, or it will be distorted. Now, loosely install the cover-to-block upper attaching screws.
  6.  
  7. Tighten the screws alternately in several stages, while you hold the cover downward and in position so that the dowels do not bind in the cover holes. Install the remaining screws and tighten alternately and in several stages to 6-8 ft. lbs. (8-11 Nm).
  8.  
  9. Install the vibration damper and water pump. Torque the vibration damper bolt to specification.
  10.  
  11. Connect the negative battery cable, refill the engine with coolant, start the engine and check for leaks.
  12.  



Click image to see an enlarged view

Fig. Fig. 5: Front cover seal installation; Chevrolet built engine shown

Diesel Engine
  1. Disconnect the negative battery cable. Drain the cooling system and disconnect the radiator hoses.
  2.  


CAUTION
When draining the coolant, keep in mind that cats and dogs are attracted by the ethylene glycol antifreeze, and are quite likely to drink any that is left in an uncovered container or in puddles on the ground. This will prove fatal in sufficient quantity. Always drain the coolant into a sealable container. Coolant should be reused unless it is contaminated or several years old.

  1. Remove all belts, fan and pulley, crankshaft pulley and balancer, using a balancer puller.
  2.  


CAUTION
The use of any other type of puller, such as a universal claw type which pulls on the outside of the hub, can destroy the balancer. The outside ring of the balancer is bonded in rubber to the hub. Pulling on the outside will break the bond. The timing mark is on the outside ring. If it is suspected that the bond is broken, check that the center of the keyway is 16 degrees from the center of the timing slot. In addition, there are chiseled aligning marks between the weight and the hub.

  1. Unbolt and remove the cover, timing indicator and water pump.
  2.  
  3. Remove the two dowel pins from the block. It may be necessary to grind a flat on each pin to get a grip on it.
  4.  

To install:
  1. Grind a chamfer on one end of each dowel pin.
  2.  
  3. Cut the excess material from the front end of the oil pan gasket on each side of the block.
  4.  
  5. Clean the block, oil pan and front cover mating surfaces with solvent and a gasket scraper.
  6.  
  7. Trim about 1 / 8 in. (3.1mm) off each end of a new front pan seal.
  8.  
  9. Install a new front cover gasket on the block and a new seal in the front cover.
  10.  
  11. Apply sealer to the gasket around the coolant holes.
  12.  
  13. Apply sealer to the block at the junction of the pan and front cover.
  14.  
  15. Place the cover on the block and press down to compress the seal. Rotate the cover left and right and guide the pan seal into the cavity using a small prybar. Oil the bolt threads and install two bolts to hold the cover in place. Install both dowel pins (chamfered end first), then install the remaining front cover bolts.
  16.  
  17. Apply a lubricant, compatible with rubber, on the balancer seal surface.
  18.  
  19. Install the balancer and bolt. Torque the bolt to specification.
  20.  
  21. Install the belts, connect the negative battery cable, refill the engine with coolant, start the engine and check for leaks.
  22.  



Click image to see an enlarged view

Fig. Fig. 6: Removing the timing chain cover attaching bolts



Click image to see an enlarged view

Fig. Fig. 7: Removing the cover from the engine



Click image to see an enlarged view

Fig. Fig. 8: Prying the old seal from the timing chain cover



Click image to see an enlarged view

Fig. Fig. 9: A seal driver or large socket can be used to install the front seal

 
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