REMOVAL & INSTALLATION
The following procedure requires the use of the GM Seal Installer/Centering tool No. J-34995 or equivalent.
- Disconnect the negative battery cable for safety.
- If equipped, remove the power steering fluid reservoir from the radiator shroud.
- Remove the upper fan shroud. Loosen and remove the accessory-to-damper pulley drive belts.
- Remove the damper pulley/hub assembly-to-crankshaft bolt and washer, then the pulley/hub assembly from the crankshaft.
The damper pulley is connected to the damper pulley hub by 3 bolts; if necessary, remove the pulley-to-hub bolts and separate the pulley from the hub. When it becomes necessary to remove the damper pulley/hub assembly, ALWAYS replace the front oil seal with a new one.
- Inspect the damper hub (oil seal surface) for rust or burrs; remove the roughness with fine emery cloth.
When installing the damper pulley hub to the crankshaft, be careful not to damage the front oil seal.
To replace the timing cover oil seal, perform the following procedures:
- Using a medium prybar, carefully pry the oil seal from the timing cover, making sure not to score the surface of the bore or the crankshaft.
- Using the GM Seal Installer/Centering tool No. J-34995 or equivalently sized driver, install the new oil seal into the timing cover, then remove the tool from the timing cover.
- Lubricate (with clean engine oil) and install the damper hub. Align it onto the keyway and push onto crankshaft.
- Install and tighten the damper pulley hub-to-crankshaft bolt to 160 ft. lbs. (217 Nm).
- Install the drive belts and check or adjust the belt tension, as applicable. For details, please refer to General Information & Maintenance of this information.
- Install the upper fan shroud.
- If equipped, install the power steering fluid reservoir to the radiator shroud.
- Connect the negative battery cable.
- Start the engine, check for leaks and proper operation.
See Figures 1, 2, 3, 4, 5, 6, 7, 8, 9 and 10
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 (1993-96 models) or an equivalent, and the GM seal installer tool No. J-35468 or equivalent.
- Disconnect the negative battery cable for safety.
- For 1985-90 vehicles, loosen and remove the accessory-to-damper pulley drive belt(s).
- For 1991-96 vehicles, remove the engine cooling fan, along with the upper and lower shrouds. For details, please refer to the procedure found earlier in this section.
Although fan and shroud removal is not required on many older vehicles covered by this guide, because of the tight working conditions, it is highly recommended.
- Remove the accessory drive belt pulley-to-damper bolts, then remove the pulley. On some models the center bolt (torsional damper bolt) is equipped with a LARGE flat washer which would prevent removal of the pulley. On these engines the pulley cannot be removed until the next step has been completed.
- Remove the damper-to-crankshaft bolt. If removal is difficult, you have 2 options. The first is to hold the crankshaft from turning (on M/T vehicles this can be done by blocking the wheels, setting the parking brake and putting the van in gear. On A/T vehicles you must use a flywheel holding tool.). The second option is to cheat the bolt through impact (an air ratchet is best, though a sharp blow on the end of a wrench or breaker bar may also do the trick) or through using a penetrating oil. If the various special tools mentioned before are not available, apply penetrating oil to the bolt and allow it to sit overnight (this usually does the trick).
- Using the a suitable torsional damper puller/installer tool (NOT AT JAWED TYPE) draw the damper from the end of the crankshaft.
When performing this operation, ALWAYS replace the front oil seal with a new one.
To replace the engine front oil seal in the timing cover, perform the following procedures (if the timing cover is being removed, this should be done after the cover is removed or during the beginning of the installation process):
- Using a medium prybar, carefully pry the oil seal from the timing cover. Take care not to score and damage the sealing surfaces and DO NOT distort the front cover.
- Coat the lips of the new seal with engine oil. The open end of the seal faces inside the engine.
- Using a suitable seal installer such as J-35468, or an equivalent sized driver, install the new oil seal into the timing cover.
- Inspect the damper (oil seal surface) for rust or burrs; remove the roughness with fine emery cloth.
When installing the damper onto the crankshaft, be careful not to damage the front oil seal.
- Lubricate the hub with engine oil, align it with the keyway and install it onto the crankshaft. Use the torsional damper puller/installer tool to slowly draw the damper into position..
If the tool is not available you MAY be able to align the damper and thread the retaining bolt a few turns, then use the hub retaining bolt to draw the damper into position. Be careful that sufficient threads are engaged first or you could strip the threads on the bolt or shaft. If the bolt cannot be started (because the distance is too great) obtain a second bolt of the same thread size, but of a longer length. You may also need some thick flat washers (in case the bolt is too long).
REMEMBER that the damper retaining bolt on some models MUST be installed AFTER the pulley (or stated another way, you may have to position the pulley before installing the damper bolt.
- Tighten the damper hub-to-crankshaft bolt to 70 ft. lbs. (95 Nm) for 1985-95 vehicles or to 74 ft. lbs. (100 Nm) for 1996 vehicles.
- If not done already, position the accessory drive belt pulley, then secure using the retaining bolts.
- If removed, install the lower shroud, followed by the engine cooling fan and upper shroud.
- Install the drive belt(s), then check and/or adjust the belt tension as applicable. For details, please refer to General Information & Maintenance of this information.
- Start the engine, then check for leaks or normal operation.