GM S10/S15/Sonoma Pick-Ups 1982-1993 Repair Manual

Rear Main Oil Seal

Print

Replacing a rear main seal is a formidable task. Before replacing the seal, care should be taken in determining the exact source of the leak. Various manufacturers produce a fluorescent die oil additive which can be added to your crankcase. The engine is run, allowing the dyed oil to leak from the same source, then a black light is used to illuminate the leak so it can be traced.

REPLACEMENT



1.9L Engine

See Figures 1 and 2

The following procedure requires the use of the seal Installer tool No. J-22928-A or equivalent

  1. Disconnect the negative battery cable.
  2.  
  3. Raise and support the front of the vehicle safely using jackstands.
  4.  
  5. Remove the starter motor and support it aside using mechanic's wire. DO NOT allow the starter to hang by the wires.
  6.  
  7. Remove driveshaft.
  8.  
  9. Support the rear of the engine and remove the transmission.
  10.  
  11. If equipped with a manual transmission, remove the clutch assembly.
  12.  
  13. Remove the flywheel-to-crankshaft bolts and the flywheel.
  14.  
  15. Remove the rear main seal retainer from the engine.
  16.  
  17. Using a medium pry bar, remove the rear main oil seal from the retainer and discard it. Be careful not to damage the retainer when removing the seal.
  18.  

To install:
  1. Lubricate the lips of the new seal and fill the space between the seal and the crankshaft with grease.
  2.  
  3. Using a seal Installer tool such as J-22928-A or equivalent, drive the new rear main oil seal into the housing.
  4.  



Click image to see an enlarged view

Fig. Fig. 1: Rear main seal mounting-1.9L engine



Click image to see an enlarged view

Fig. Fig. 2: Rear main seal installation-1.9L engine

  1. Install the rear main seal retainer to the engine.
  2.  
  3. Position the flywheel, then secure using the flywheel-to-crankshaft bolts.
  4.  
  5. If equipped with a manual transmission, install the clutch assembly.
  6.  
  7. Install the transmission and remove the temporary support at the rear of the engine.
  8.  
  9. Install driveshaft.
  10.  
  11. Reposition and secure the starter motor.
  12.  
  13. Remove the jackstands and carefully lower the vehicle.
  14.  
  15. Connect the negative battery cable.
  16.  

2.0L and 2.8L Engines

See Figure 3

There are 2 sizes of seals used on these engines; 5mm and 11mm. The 5mm seal is available for 1 and 2 piece applications, while the 11mm seal is available only as a one piece design. Early models of the 2.0L and 2.8L engines may be equipped with any of these seals. Later models of the 2.0L engine will tend to be equipped with either of the 1 piece designs, while later models of the 2.8L engine are equipped with the 11mm one piece rear main seal.

To determine the type of oil seal on 2.0L engines, it will be necessary to look for an identification mark (oval) stamped on the right rear side of the engine where it connects to the transmission. If the oval appears, the engine uses an 11mm second design (one-piece) seal. If the oval does not appear the engine uses a 5mm first design seal. The first design seals may come in either a one or two piece configuration.



Click image to see an enlarged view

Fig. Fig. 3: Seal identification mark-2.0L engine

On 2.8L engines, the year of the engine (usually same as the vehicle) determines the seal used as follows:



1982-85 engines use a 5mm first design rear main seal.
 
1986-93 engines use an 11mm second design rear main seal.
 

5MM TWO PIECE

See Figure 4

  1. Remove the oil pan.
  2.  
  3. Remove the oil pump.
  4.  
  5. Remove the rear main bearing cap.
  6.  
  7. Remove the upper and lower seal. Be careful when removing the upper seal not to score the crankshaft or sealing surface. Clean the seal channel of any oil.
  8.  

To install:

To install the replacement seal, you may need to loosen numbers 2, 3, and 4 rear main bearing caps.



Click image to see an enlarged view

Fig. Fig. 4: Applying sealant to the rear main bearing cap-2.0L and 2.8L engines with the 5mm 2-piece seal

  1. Apply a very thin coat of gasket sealant to the outside diameter of the upper seal. Install the seal with the lip inward, turning the crankshaft to ease installation.
  2.  
  3. Install the lower seal in the rear main bearing cap after applying sealant to the outside diameter.
  4.  
  5. Check the bearing clearance of the rear main bearing with Plastigage®. Repair as necessary if out of specification.
  6.  
  7. Lightly oil the rear main bearing after removing the Plastigage®. Apply a 1mm bead of RTV to the rear main bearing cap between the rear main seal end and the oil pan rear seal groove. DO NOT allow sealant to come in contact with the rear main seal or the drain slot.
  8.  
  9. Lightly oil the rear main seal and install the rear main bearing cap. Torque the cap bolts to specification.
  10.  
  11. Install the oil pump.
  12.  
  13. Install the oil pan.
  14.  

5MM ONE PIECE

See Figure 5

  1. Remove the engine from the vehicle.
  2.  
  3. Remove the oil pan, then remove the oil pump.
  4.  
  5. Remove the front (timing) cover and lock the chain tensioner with a pin.
  6.  
  7. Rotate the crankshaft until the timing marks on the cam and crank sprockets line up.
  8.  
  9. Remove the camshaft bolt, cam sprocket and timing chain.
  10.  
  11. Rotate the crankshaft to a horizontal position and remove the rod bearing nuts, caps and bearings.
  12.  

The rod bearings and caps must be replaced in order. DO NOT mix them up.

  1. Remove the main bearing bolts, caps and bearings. Remove the crankshaft.
  2.  
  3. Remove the old rear main seal and clean the sealant from the crankshaft and block.
  4.  

To install:
  1. Apply a light coat of sealant to the outside diameter of the replacement seal.
  2.  
  3. Place a Seal Tool assembly on the rear area of the crankshaft. Position the seal tool so that the arrow points toward the engine. Place the crankshaft in the engine with the tool in this position. Remove and discard the tool.
  4.  
  5. Seal the rear main bearing split line (use sealant No. 1052756) and replace the rear main bearing and cap.
  6.  
  7. Replace the other bearings and caps, then tighten bolts to specification.
  8.  
  9. Replace the rod bearings and caps, then tighten the bolts to specification.
  10.  
  11. Install the oil pump.
  12.  
  13. Align the crank sprocket timing mark, then install the cam sprocket and timing chain.
  14.  
  15. Install the engine front cover.
  16.  
  17. Install the oil pan.
  18.  
  19. Install the engine.
  20.  



Click image to see an enlarged view

Fig. Fig. 5: Installing the 5mm one piece rear seal.

11MM ONE PIECE

See Figures 6 and 7

The following procedure requires the use of a seal installation tool such as J-34686 or equivalent.

  1. Remove the transmission assembly.
  2.  
  3. Remove the flywheel and verify the rear main seal is leaking.
  4.  
  5. Remove the seal by inserting a small prybar through the dust lip at an angle and prying the seal out. Be careful not to score the crankshaft sealing surface.
  6.  

To install:


Click image to see an enlarged view

Fig. Fig. 6: Prying out the 11mm rear main seal-2.0L and 2.8L engines

  1. Check the crankshaft and seal bore for nicks or damage. Repair as necessary.
  2.  
  3. Lightly coat the inner diameter of the seal with clean engine oil.
  4.  
  5. Position the seal over the mandrel of the J-34686 or an equivalent installation tool. Make sure the dust lip (back of seal) is bottomed squarely against the collar of the tool.
  6.  
  7. Lightly coat the outer diameter of the seal using clean engine oil, then position the tool to the crankshaft while aligning the tool dowel pin with the crankshaft dowel pin hole. Tighten the screws to attach the tool and assure proper seal installation.
  8.  
  9. Turn the handle of the tool until the collar is tight against the case and the seal has been completely seated.
  10.  
  11. Turn the handle of the tool out until it stops, then remove the tool and verify that the is seated squarely in the bore.
  12.  
  13. Install the flywheel.
  14.  
  15. Install the transmission assembly.
  16.  



Click image to see an enlarged view

Fig. Fig. 7: Installing the 11mm rear main seal

2.2L Diesel Engine

See Figure 8

The following procedure requires the use of a seal installation tool such as J-22928 or equivalent.

  1. Raise and support the front of the truck safely using jackstands.
  2.  
  3. Remove the transmission assembly.
  4.  
  5. If equipped with a manual transmission, remove the clutch assembly.
  6.  
  7. Remove the flywheel-to-crankshaft bolts, then remove the flywheel.
  8.  
  9. Using a medium pry bar, carefully pry the rear main seal from the rear of the engine.
  10.  

To install:
  1. Using clean engine oil, lubricate the lips of the new seal.
  2.  
  3. Using a seal installation tool such as J-22928 or equivalent, drive the new seal into the rear of the engine until it seats.
  4.  



Click image to see an enlarged view

Fig. Fig. 8: Rear main seal installation-2.2L diesel engine

  1. Install the flywheel and secure using the flywheel-to-crankshaft bolts.
  2.  
  3. If equipped, install the clutch and pressure plate.
  4.  
  5. Install the transmission assembly.
  6.  
  7. Remove the jackstands and carefully lower the truck.
  8.  

2.5L and 4.3L Engine

The following procedure requires the use of a seal installation tool (such as J-34924 for the 2.5L and J-35621 for the 4.3L) or equivalent.

  1. Remove the transmission assembly.
  2.  
  3. If equipped, remove the clutch assembly.
  4.  
  5. Remove the flywheel and verify the rear main seal is leaking.
  6.  
  7. Remove the seal by inserting a small prybar through the dust lip at an angle and prying the seal out. Be careful not to score the crankshaft sealing surface.
  8.  

To install:
  1. Check the crankshaft and seal bore for nicks or damage. Repair as necessary.
  2.  
  3. Lightly coat the inner and outer diameters of the seal with clean engine oil, then position the seal on the installation tool.
  4.  
  5. Position the tool to the crankshaft and thread the tool's screws into the tapped holes. Tighten the screws securely using a screwdriver to attach the tool and assure proper seal installation.
  6.  
  7. Turn the handle of the tool until it bottoms and the seal has been completely seated.
  8.  
  9. Turn the handle of the tool out until it stops, then remove the tool and verify that the is seated squarely in the bore.
  10.  
  11. Install the flywheel to the engine.
  12.  
  13. If equipped, install the clutch assembly.
  14.  
  15. Install the transmission assembly.
  16.  

 
label.common.footer.alt.autozoneLogo