Accepted Answer

Timing Belt and Tensioner

REMOVAL & INSTALLATION

Fig. 1: Straighten out a standard paper clip, then form a double loop as shown

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Fig. 2: Timing belt routing — 1996 3.4L engine shown

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Fig. 3: Timing belt removal — 3.4L engines

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Fig. 4: Timing belt tensioner actuator and plate removal and installation

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1991–95 3.4L Engines

1. Disconnect the negative battery cable.

   NOTE: Siphon the power steering fluid from the reservoir before disconnecting the lines to avoid spilling fluid on the timing belt cover. Use shop rags when disconnecting the lines to insure any remaining fluid does NOT contact the timing belt cover. Power steering fluid can damage the timing belt.

2. Remove secondary timing belt actuator/tensioner, as follows:
   1. Remove the power steering pump, as outlined in Section 8.
   2. Remove the camshaft timing belt covers, as outlined earlier in this section.
   3. Rotate the engine clockwise to align the timing marks on the camshaft sprockets and crankshaft balancer to the front cover, if the marks are visible. If no timing marks are present, rotate the crankshaft to align the crankshaft balancer mark to the cast front cover timing arrow. Mark the camshaft sprocket teeth facing each other with a permanent marker, for installation reference.
   4. Loosely clamp the two camshaft sprockets on each side of the engine together using clamping pliers or equivalent. No deflection of the cam sprockets should be noted, if deflection is noted, loosen the clamping device.
   5. Remove the bolts and side plate from the tensioner.
   6. Rotate the tensioner assembly from the tensioner pulley socket and out of the mounting base. Removal of the tensioner from the tensioner pulley allows it to extend to its maximum travel.

      NOTE: Do not install a rod tip or tensioner boot in the jaws of a vise or damage to the assembly may occur.

   7. Position the tensioner in a vertical position in a vise (rod tip down), then tensioner body in the vise lightly. Allow the oil to drain to the boot end, for at least 5 minutes before refilling.
   8. Straighten out a paper clip (0.032 in. diameter, no serrations) to a minimum straight length of 1.85 in. (47mm). Form a double loop in the remaining end of the paper clip.
   9. Remove the rubber end plug from the rear of the tensioner assembly. The assembly is filled with oil and removal of the plug may allow oil to escape. Do NOT remove the vent plug.
   10. Push the paper clip through the center hole in the vent plug and into the pilot hole.
   11. Insert a small screwdriver into the screw slot inside the tensioner, behind the rubber end plug.
   12. Retract the tensioner plunger by rotating the screw in a clockwise direction, until it is fully retracted. Push on the paper clip and slowly rotate the screw counterclockwise until the paper clip engages.
   13. If tensioner oil has been lost, fill the tensioner with synthetic engine oil through the end hole. Fill to the bottom of the plug hole ONLY when the tensioner is fully retracted and the pin is installed.
3. If the belt is to be reused, mark direction of rotation for installation purposes.
4. Remove tensioner and pulley arm assembly by removing the tensioner pulley bolt and remove the arm. The pivot bushing can fall out. Hold in the pulley with a flat magnet, tape or cup plug.
5. Remove timing belt by sliding off of pulleys. Do not bend, twist, or kink belt or damage to the belt may occur.

   To install:

6. Install new belt or old belt taking note of direction of rotation.
7. Install the tensioner pulley to the mounting base. Tighten the bolt to 37 ft. lbs. (50 Nm).
8. Rotate the tensioner pulley counterclockwise into the belt using the cast square lug on body and engage ball end of the actuator into socket on pulley arm.
9. Remove the tensioner lockpin, allowing tensioner shaft to extend and the pulley to move into the belt.
10. Rotate the tensioner pulley counterclockwise applying 12–15 ft. lbs. (16–20 Nm) of torque.
11. Rotate the engine clockwise 3 times to seat belt. Align the crankshaft reference marks during final rotation to TDC. Do NOT allow crankshaft to spring back or reverse direction of rotation.
12. Seat the lockring on the right exhaust and right intake camshaft into the bore by threading in the attaching bolts.
13. Hold the sprocket from turning, using tool J–38614 or equivalent. Tighten the attaching bolt to 81 ft. lbs. (110 Nm), taking note of running torque; torque required to turn bolt before seating. Running torque of bolt should be 44–66 ft. lbs. (60–89 Nm). If less torque is required, replace the shim and lockrings and inspect the nose of the camshaft for brinelling. If more torque is required than replace the shim and lockrings and check the attaching bolt threads for burrs or foreign material.
14. Rotate engine clockwise 1 revolution and realign the balancer marks at TDC. Make sure timing mark on damper lines up with front cover timing mark.
15. Repeat steps, starting with left intake then left exhaust camshaft.
16. Install secondary timing belt covers and retaining bolts.
17. Connect negative battery cable.

1996 3.4L Engines

1. Disconnect the negative battery cable.
2. Remove the air cleaner assembly. Properly drain the engine coolant into a suitable container.
3. Disconnect the control cables from the throttle body.
4. Remove the fuel injector sight shield.
5. Relieve the fuel system pressure, as outlined in Section 5 of this manual.
6. Disconnect and cap the fuel lines from the fuel rail.
7. Remove the fuel mounting bracket.
8. Detach the heater hose and remove the bracket from the lower intake manifold.
9. Disconnect the PCV valve and the vacuum line from the throttle body.
10. Detach the EGR valve electrical connector, unfasten the retaining bolts, then remove the EGR valve from the upper intake and position it aside.
11. Disconnect the electrical connectors from the canister purge solenoid and MAP sensor.
12. Tag and disconnect the vacuum lines from the upper intake manifold tee.
13. Remove the wiring loom bracket from the rear band spark plug wires.
14. Detach the power brake vacuum hose.
15. Unfasten the nuts at the upper intake manifold support bracket.
16. Remove the upper intake manifold, as outlined earlier in this section.
17. Remove the coolant recovery tank.
18. Remove the serpentine drive belt and belt tensioner.
19. Remove the power steering pump, as outlined in Section 8 of this manual.
20. Detach the PCM electrical connectors.
21. Tag and disconnect the spark plug wires from the plugs.
22. Remove the wiring harness cover from the right strut tower.
23. Remove the fuel line bracket.
24. Remove the timing belt covers, as outlined earlier in this section.
25. Disconnect the breather hose from the rear camshaft cover and crankcase vent from the breather manifold.
26. Remove the camshaft carrier covers.
27. Remove the bolts and the side plate from the tensioner actuator.
28. Rotate the tensioner actuator from the tensioner actuator pulley socket and out of the mounting base. The removal of the tensioner actuator from the tensioner actuator pulley allow it to extend to its maximum travel.

    NOTE: Do not install a rod tip or tensioner boot in the jaws of a vise or damage to the assembly may occur.

29. Position the tensioner in a vertical position in a vise (rod tip down), then tensioner body in the vise lightly. Allow the oil to drain to the boot end, for at least 5 minutes before refilling.
30. Straighten out a paper clip (0.032 in. diameter, no serrations) to a minimum straight length of 1.85 in. (47mm). Form a double loop in the remaining end of the paper clip.
31. Remove the rubber end plug from the rear of the tensioner assembly. The assembly is filled with oil and removal of the plug may allow oil to escape. Do NOT remove the vent plug.
32. Push the paper clip through the center hole in the vent plug and into the pilot hole.
33. Insert a small screwdriver into the screw slot inside the tensioner, behind the rubber end plug.
34. Retract the tensioner plunger by rotating the screw in a clockwise direction, until it is fully retracted. Push on the paper clip and slowly rotate the screw counterclockwise until the paper clip engages.
35. Remove the timing belt from the vehicle. Remove the timing marks from the camshaft and intermediate shaft sprockets.
36. Rotate the crankshaft to the No. 1 cylinder is at TDC. Mark the timing indicator with white paint or equivalent on the crankshaft balancer and front cover.
37. Position the camshaft so the flat spots are up for installation of tool J 38613-A.

    NOTE: Make sure the bolt hole is free of any debris before installing J 38613-A or the camshaft carrier may be damaged.

38. Install tool J 38613-A on both camshaft carriers.
39. Remove the camshaft sprockets. Remove the bolts, taper lockrings and sprockets by lightly tapping on it with a soft faced hammer.

    To install:

40. Install the camshaft sprockets finger-tight.
41. Route the timing belt in a counterclockwise direction around the sprockets. Make sure all of the timing belt teeth are fully engaged with all sprockets.
42. Install the timing belt tensioner actuator pulley. Tighten the retaining bolt/screw to 37 ft. lbs. (50 Nm).
43. If tensioner oil has been lost, fill the tensioner with synthetic engine oil through the end hole. Fill to the bottom of the plug hole ONLY when the tensioner is fully retracted and the pin is installed.
44. Install the rubber end plug to the rear of the tensioner actuator. Push until flush and snapped into place. Make sure the end plug has sealed against the case.
45. Install the tensioner actuator bushing into the side plate.
46. Install the tensioner actuator and side plate. Make sure the tapered fulcrum of the tensioner actuator is properly seated in the tensioner actuator bracket bushing. Tighten the retaining bolts to 18 ft. lbs. (25 Nm).

    NOTE: Rotate the pulley into the belt a maximum of 11 ft. lbs. (15 Nm) to allow engagement of the actuator shaft into the pulley arm socket.

47. Pull the lockpin and discard. Retighten the pulley to 15 Nm counterclockwise to seat the pulley into the belt.
48. Install both right hand (rear bank) camshaft sprockets. Tighten the bolts to 96 ft. lbs. (130 Nm).
49. Remove tool J 38613-A from the right hand (rear bank) camshaft carrier.
50. Rotate the crankshaft 360°clockwise while looking at the front of the engine and align the crankshaft reference marks.
51. Make sure both right hand camshaft flats are down, then tighten both left hand (front bank) camshaft sprockets to 96 ft. lbs. (130 Nm).
52. Remove tool J 38613-A from the left hand (front bank) camshaft carrier.
53. Rotate the crankshaft 720°clockwise while looking at the front of the engine to seat the timing belt and verify correct timing. Make sure both camshaft flat spots are up on one band and down on the opposing bank.
54. Install the camshaft carrier covers.
55. Connect the breather hose to the rear camshaft cover and crankcase vent to the breather manifold.
56. Install the camshaft timing belt covers, as outlined earlier in this section.
57. Install the fuel line bracket and bolt.
58. Install the wiring harness cover at the right strut tower.
59. Connect the spark plug wires, as tagged during removal.
60. Attach the PCM electrical connectors.
61. Connect the power steering lines to the pump.
62. Install the serpentine drive belt and tensioner.
63. Install the coolant recovery tank.
64. Install the upper intake manifold, using a new gasket. Tighten the retaining bolts to 19 ft. lbs. (26 Nm).
65. Fasten the nuts at the upper intake manifold support bracket. Tighten the nuts to 18 ft. lbs. (25 Nm).
66. Connect the power brake vacuum hose.
67. Install the wiring loom bracket for the rear spark plug wires.
68. Connect the vacuum lines to the upper intake manifold tee.
69. Attach the electrical connectors to the canister purge solenoid and MAP sensor.
70. Install the EGR valve, secure with the retaining bolts, then attach the connector.
71. Connect the PCV valve and vacuum line to the throttle body.
72. Install the heater hose and bracket to the lower intake manifold.
73. Install the fuel line bracket and bolt. Uncap and connect the fuel pipes to the fuel rail.
74. Install the fuel injector sight shield.
75. Connect the control cables to the throttle body.
76. Install the air cleaner assembly. Refill the cooling system and refill and bleed the power steering system. Connect the negative battery cable.

2 special tools required if doing a broken belt repair

http://www.etoolcart.com/index.asp?PageAction=VIEWPROD&ProdID=1037

http://www.etoolcart.com/index.asp?PageAction=VIEWPROD&ProdID=1036

Edited by crazi429 on 6/10/2006 at 2:50 PM

Expert:	Tim Basham
Pos. Feedback:	100.0 %
Accepts:	170
Answered:	6/10/2006

ASE Certified Master Technician

30 years multi line tech ASE cert master tech ASE engine machinist, 9 years GM dealer exp.