GM Astro/Safari 1985-1996 Repair Guide

Timing Cover and Front Oil Seal

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REMOVAL & INSTALLATION



2.5L Engine

See Figures 1, 2 and 3



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Fig. Fig. 1: Exploded view of the crankshaft pulley, damper/hub and timing gear cover assembly-2.5L engine



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Fig. Fig. 2: Apply RTV sealer to the timing gear cover as shown



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Fig. Fig. 3: GM seal installer and centering tool

This procedure requires the use of the GM Seal Installer/Centering tool No. J-34995 or equivalent.

  1. Disconnect the negative battery cable for safety.
  2.  
  3. Refer to the Crankshaft Pulley, Damper and Oil Seal, Removal and Installation procedures in this section and remove the damper from the crankshaft.
  4.  
  5. If not done already, remove the fan and the pulley.
  6.  
  7. Remove the alternator and the brackets from the front of the engine.
  8.  
  9. Remove the lower radiator hose clamp at the water pump.
  10.  
  11. Remove the timing cover bolts and cover. Check for bolts threaded from the front of the oil pan to the bottom of the cover. If present, these must be removed before attempting to loosen the cover.
  12.  
  13. If the front seal is to be replaced, it can be pried out of the cover with a small prytool.
  14.  
  15. Using a plastic scraper, clean the gasket mounting surfaces. Then clean the surface with solvent to remove all traces of oil and grease.
  16.  

The timing cover can become distorted very easily, so be careful when cleaning the gasket surface.

To install:
  1. Apply engine oil to the lips of the new oil seal. Using the GM Seal Installer/Centering tool No. J-34995 or equivalent, install the new oil seal into the timing cover; leave the tool installed in the timing cover.
  2.  
  3. Using RTV sealant or equivalent, apply a 1 / 4 in. (6mm) wide bead to the timing cover mounting surface and a 3 / 8 in. (9.5mm) wide bead to the oil pan at the timing cover sealing surface.
  4.  
  5. Using the GM Seal Installer/Centering Tool J-34995 or equivalent, align the front cover. Install the cover while the RTV sealant is still wet and finger-tighten the retainers.
  6.  
  7. Tighten the timing cover-to-engine bolts to 90 inch lbs. (10 Nm) first, then, tighten the timing cover-to-oil pan bolts to 90 inch lbs. (10 Nm). Remove the seal installer/centering tool from the timing cover.
  8.  
  9. Install the lower radiator hose clamp to the water pump.
  10.  
  11. Install the alternator and the brackets at the front of the engine.
  12.  
  13. Install crankshaft damper and pulley. For details, please refer to the procedure found earlier in this section.
  14.  
  15. If not done already, install the fan and the pulley.
  16.  
  17. Connect the negative battery cable, start the engine and check for leaks.
  18.  

4.3L Engine

See Figures 4, 5, 6 and 7



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Fig. Fig. 4: Loosen and remove the timing cover retaining bolts ...



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Fig. Fig. 5: ... then carefully break the gasket seal and ...



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Fig. Fig. 6: ... remove the cover from the engine



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Fig. Fig. 7: If you install a replacement front seal with the cover OFF the engine, BE SURE TO SUPPORT IT to prevent damage

1985-95 Models

The following procedure requires the use of a torsional damper puller/installer tool such as GM tool no. J-23523-E (1985-92 models), J-39046 (1993-95 models) or an equivalent, and the GM Seal Installer tool No. J-35468 or equivalent.

  1. Disconnect the negative battery cable for safety.
  2.  
  3. Remove the water pump assembly from the engine. For details, please refer to the procedure found earlier in this section.
  4.  
  5. Remove the crankshaft pulley and damper. For details, please refer to the procedure found earlier in this section.
  6.  
  7. Either loosen or remove the oil pan, as necessary. For 1985-91 models the manufacturer recommends that the oil pan be removed. For 1992-95 models the manufacturer recommends that the pan just be loosened. It is possible that this can be done on earlier models as well, but caution must be taken to prevent front cover and oil pan seal damage.
  8.  
  9. For 1995 vehicles, remove the crankshaft position sensor.
  10.  
  11. Remove the timing cover-to-engine bolts, then carefully remove the cover from the engine. If the oil pan was not removed, be careful not to damage the oil pan-to-front cover seal or sealing surfaces.
  12.  
  13. Using a plastic scraper, clean the gasket mounting surfaces. Using solvent and a rag, clean the oil and grease from the gasket mounting surfaces.
  14.  
  15. If the front cover seal is to be replaced, it may be pried front the front cover using a suitable prytool. Take care not to score and damage the seal bore, and take even greater care NOT TO distort the cover metal.
  16.  
  17. Inspect the timing cover for distortion and damage, if necessary, replace it.
  18.  

To install:

Beginning in 1992, the manufacturer began suggesting you wait until the front cover is mounted to the engine before you install the replacement crankshaft oil seal. This may be to assure the cover is properly supported. On earlier vehicles, the manufacturer allowed for installation with the cover removed or installed, so waiting would be acceptable for all years of the 4.3L engine.

  1. If desired on early-model engines, install a new seal to the cover using a suitable installation driver, such as J-35468 or equivalent. Be sure to support the back of the seal cover area during installation to prevent the cover from becoming distorted or damaged. Lightly coat the lips of the new seal with clean engine oil.
  2.  

The oil seal is installed with the open end of the seal lips facing toward the inside of the engine.

  1. Position a new front cover gasket to the engine or cover using a high-tack gasket cement to hold it in position. If the oil pan was not removed, lubricate the front of the oil pan seal with clean engine oil to aid in reassembly.
  2.  
  3. Install the front cover to the engine. If the oil pan is still in place, take care while engaging the front of the oil pan seal with the bottom of the cover.
  4.  
  5. Install front cover retaining bolts and tighten to 124 inch lbs. (14 Nm).
  6.  

Tighten the timing cover bolts alternately and evenly, while gently pressing on the cover.

  1. If removed and not installed earlier, use the seal installation driver to install the new crankshaft seal at this time.
  2.  
  3. For 1995 vehicles, install the crankshaft position sensor.
  4.  
  5. Either secure or install the oil pan, depending on your decision earlier.
  6.  
  7. Install the crankshaft damper and pulley.
  8.  
  9. Install the water pump assembly.
  10.  
  11. Connect the negative battery cable, the properly refill and bleed the engine cooling system.
  12.  
  13. Run the engine and check for leaks.
  14.  

1996 Models

The 1996 4.3L engine covered by this guide uses a composite engine front cover which must be discarded if it is removed from the engine. If a composite front cover is reused there is a good chance that it will leak.

  1. Disconnect the negative battery cable for safety.
  2.  
  3. Remove the water pump assembly from the engine. For details, please refer to the procedure found earlier in this section.
  4.  
  5. Remove the crankshaft pulley and damper. For details, please refer to the procedure found earlier in this section.
  6.  
  7. Loosen the oil pan to help provide clearance for front cover removal without damaging the front cover-to-oil pan seal.
  8.  
  9. Remove the crankshaft position sensor.
  10.  
  11. Remove the timing cover-to-engine bolts, then carefully remove the cover from the engine. Be careful not to damage the oil pan-to-front cover seal or sealing surfaces.
  12.  
  13. Discard the old timing cover.
  14.  
  15. Using a plastic scraper, solvent and a rag, clean the oil, grease and varnish from the mounting surfaces on the engine.
  16.  

To install:
  1. Lubricate the front of the oil pan seal with clean engine oil to aid in reassembly.
  2.  
  3. Install the new front cover to the engine, then tighten the front cover retaining bolts to 124 inch lbs. (14 Nm).
  4.  

Tighten the timing cover bolts alternately and evenly, while gently pressing on the cover.

  1. Install the crankshaft position sensor.
  2.  
  3. Secure the oil pan.
  4.  
  5. Install the crankshaft damper and pulley.
  6.  
  7. Install the water pump assembly.
  8.  
  9. Connect the negative battery cable, the properly refill and bleed the engine cooling system.
  10.  
  11. Run the engine and check for leaks.
  12.  

 
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