Timing chain cover, chain and sprockets – removal, inspection and installation
Warning: Wait until the engine is completely cool before beginning this procedure. Caution: The timing system is complex, and severe engine damage will occur if you make any mistakes. Do not attempt this procedure unless you are highly experienced with this type of repair. If you are at all unsure of your abilities, be sure to consult an expert. Double-check all your work and be sure everything is correct before you attempt to start the engine. Caution: Do not rotate the crankshaft or camshafts separately during this procedure (with the timing chains removed), as damage to the valves will occur.
Note: Several special tools are required to complete these procedures, so read through the entire Section and obtain the special tools before beginning work.
Removal
Timing chain cover
1. Disconnect the negative battery cable from the remote ground terminal (see Engine electrical systems).
2. Drain the engine coolant and engine oil (see Tune-up and routine maintenance).
3. Remove the air intake resonator (see Fuel and exhaust systems – gasoline engines).
4. Remove the brake vacuum pump (see Brakes).
5. Remove the drivebelt, drivebelt tensioner and both idler pulleys (see Tune-up and routine maintenance).
6. Remove the thermostat housing and radiator hoses, and disconnect the heater hose from the water pump (see Cooling, heating and air conditioning systems).
7. Remove the heater core supply pipe fasteners from the rear cylinder head and move the pipe out of the way.
8. Remove the alternator (see Engine electrical systems).
9. Remove the crankshaft pulley (Crankshaft pulley – removal and installation).
10. Remove the upper intake manifold (Intake manifolds – removal and installation).
11. Remove the valve covers (Valve covers – removal and installation).
Caution: Once the valve covers are removed, the magnetic timing wheels are exposed (see illustration 9.9). The magnetic timing wheels on the camshafts must not come in contact with any type of magnet or magnetic field. If contact is made, the timing wheels will have to be replaced.
12. Remove the upper and lower oil pans (Oil pans – removal and installation).
13. Remove the timing chain cover (M6-size) mounting bolts (see illustration). There are seven indented prying points; one on top and three on each side; carefully pry the cover free of the engine block and cylinder heads. If it still sticks, slip a putty knife between the engine block and cover to break the bond (but be careful not to scratch the surfaces).
8.13 Timing chain cover bolt locations (1) – M6 size bolts
14. If necessary, remove the coolant outlet housing and water pump from the timing chain cover (see Cooling, heating and air conditioning systems).
Timing chain
Warning: When the timing chains are removed, do not rotate the camshafts or crankshaft; the valves and pistons can be damaged if contact is made.
15. Temporarily install the crankshaft pulley bolt. Turn the crankshaft with the bolt to TDC number 1, on the exhaust stroke to align the timing marks on the crankshaft and camshaft sprockets. Rotate the engine clockwise only, until the mark on the crankshaft aligns with the line made where the engine block and bearing cap meets (see illustration).
8.15 Align the dimple (A) on the crankshaft with the line (B) made where the engine block and bearing cap meets
16. On the left-side camshaft phaser, the machined scribe lines should be facing away from each other, and the arrows should be pointing towards each other in a parallel line with the gasket surface of the cylinder head. On the right-side camshaft phaser, the arrows should be facing away from each other and the machined scribe lines should be pointing towards each other in a parallel line with the gasket surface of the cylinder head (see illustrations 9.10a and 9.10b). If, when you align the crankshaft mark with the bearing cap parting line, the camshaft marks are not in alignment as shown in illustration 8.59, rotate the engine one full revolution, realign the crankshaft mark, and verify that the camshaft marks are in proper alignment.
17. Verify the phaser marks are aligned with the plated links; if the plated links cannot be distinguished, make sure there are 12 pins between the two marks (see illustration).
8.17 Verity that there are 12 pins between the mark on each phaser
Note: Use paint or a permanent marker to mark the direction of rotation on all chains before removing them so they can be installed in the same direction.
18. Starting with the right side chain tensioner, press the tensioner plunger in until special tool #8514 or a 3 mm Allen wrench can be inserted through both small holes in the top and bottom of the tensioner body, holding the plunger in the compressed position.
19. Working on the left side chain tensioner, locate the access hole on the side of the tensioner. Working through the hole, lift and hold the pawl off of the rack of the plunger in the tensioner. Press the plunger in until special tool #8514 or a 3 mm Allen wrench can be inserted through both small holes in the top and bottom of the tensioner body, holding the plunger in the compressed position.
20. Remove the timing gear splash shield fasteners, then remove the shield from the oil pump housing.
21. Remove the oil pump tensioner and sprocket (Oil pump – removal, inspection and installation), then remove the oil pump chain from the crankshaft gear.
Note: The oil pump chain and sprocket do not have to be timed, but the chain should be marked to make sure it is installed in the same direction of rotation.
22. Starting with the right-side chain, slide camshaft phaser lock tool #10202-1 from the front, between the two camshaft phasers, towards the chain (with the tool number facing up).
Note: It may be necessary to rotate the intake camshaft a few degrees using a wrench on the camshaft flat when installing the phaser lock tool.
23. Using a large wrench on the camshaft flats and a socket and ratchet on the oil control valves, loosen, but do not remove, the oil control valves.
24. Remove the right side camshaft phaser lock tool, then unscrew the intake camshaft oil control valve from the center of the phaser.
25. Slide the intake camshaft phaser off of the end of the camshaft, then remove the right-side timing chain.
Note: If necessary, remove the exhaust camshaft oil control valve from the center of the phaser and remove the phaser.
26. Working on the left-side chain, slide camshaft phaser lock tool #10202-2 from the front, between the two camshaft phasers, towards the chain (with the tool number facing up).
Note: It may be necessary to rotate the intake camshaft a few degrees using a wrench on the camshaft flat when installing the phaser lock tool.
27. Using a large wrench on the camshaft flats and a socket and ratchet on the oil control valves, loosen, but do not remove, the oil control valves
28. Remove the left-side camshaft phaser lock tool, then unscrew the exhaust camshaft oil control valve from the center of the phaser.
29. Slide the exhaust camshaft phaser off of the end of the camshaft, then remove the left side timing chain.
Note: If necessary, remove the intake camshaft oil control valve from the center of the phaser and remove the phaser.
30. Locate the primary chain tensioner to the side of the crankshaft chain and press the tensioner plunger in until special tool #8514 or a 3 mm Allen wrench can be inserted through the small hole in the side of the tensioner body, holding the plunger in the compressed position.
31. With the tensioner in the compressed position, remove the TORX (T30) mounting fasteners and the tensioner.
32. Remove the primary chain guide TORX (T30) mounting fasteners and the guide.
33. Remove the idler sprocket TORX (T45) mounting fastener and washer, then remove the idler sprocket, primary chain and crankshaft sprocket.
Note: The chain should be marked to make sure it is installed in the same direction of rotation.
34. If necessary, remove the chain tensioner (T30) fasteners and remove the tensioner(s), keeping the tensioners in the compressed position.
35. If necessary, remove the chain guide fasteners and guides for both chains.
Inspection
36. Inspect the timing chain dampener (guide) for cracks and wear and replace it, if necessary.
37. Clean the timing chain and sprockets with solvent and dry them with compressed air (if available).
Warning: Wear eye protection when using compressed air.
38. Inspect the components for wear and damage. Look for teeth that are deformed, chipped, pitted, and cracked.
39. The timing chain and sprockets should be replaced with new ones if the engine has high mileage, the chain has visible damage, or total freeplay midway between the sprockets exceeds one inch. Failure to replace a worn timing chain and sprockets may result in erratic engine performance, loss of power, and decreased fuel mileage. Loose chains can jump timing. In the worst case, chain jumping or breakage will result in severe engine damage.
Installation
Caution: Before starting the engine, carefully rotate the crankshaft by hand through at least two full revolutions (use a socket and breaker bar on the crankshaft pulley center bolt). If you feel any resistance, STOP! There is something wrong – most likely, valves are contacting the pistons. You must find the problem before proceeding.
40. Use a plastic gasket scraper to remove all traces of old gasket material and sealant from the cover, engine block and cylinder heads. The cover is made of aluminum, so be careful not to nick or gouge it. Only clean the gasket sealing surfaces with rubbing alcohol (isopropyl) – do not use any oil based fluids.
41. If removed, install the chain guides and tensioners (still in the compressed position).
42. Make sure the keyway is installed on the crankshaft and the dimple on the crankshaft is aligned with the line made where the engine block and bearing cap meets (see illustration 8.15).
43. Verify the camshafts are at TDC, with the alignment holes pointing up (see illustration 9.29).
44. Place the primary chain on the crankshaft sprocket, with the plated link of the primary chain aligned with the arrow on the bottom of the sprocket. Insert the idler sprocket into the chain, aligning the other plated link with the machined mark on the idler sprocket.
45. Using clean engine oil, coat the sprockets and chain. Install the assembly while keeping the marks aligned, then install the idler sprocket mounting fastener finger tight.
46. Check the alignment of the marks; the plated link on the idler sprocket should be on top (12 o’clock) and the machined mark on the crankshaft should be aligned with the line made where the engine block and bearing cap meet (see illustration). If the marks are all aligned, tighten the idler sprocket fastener to the torque listed in this Chapter’s Specifications.
8.46 Primary chain alignment details
47. Install the primary chain guide and tensioner, then tighten the fasteners to the torque listed in this Chapter’s Specifications. Remove the special tool from the tensioner plunger.
48. Starting with the left-side chain, install the intake camshaft phaser and oil control valve, then tighten the valve finger tight.
49. Place the left side chain over the intake phaser and around the inside cogs of the idler sprocket so that the plate link of the chain is aligned with the machined arrow on the sprocket.
50. With the chain aligned at the idler sprocket, install the exhaust camshaft phaser so that the arrows are pointing towards each other and in a parallel line with the cylinder head gasket surface (see illustration 9.10a), then install the oil control valve finger tight.
51. Slide camshaft phaser lock tool #10202-2 from the front, between the two camshaft phasers towards the chain with the tool number facing up.
52. Using a large wrench on the camshaft flats and a socket and ratchet on the oil control valves, tighten both valves to the torque listed in this Chapter’s Specifications.
53. Working on the right-side chain, install the exhaust camshaft phaser and oil control valve, tightening the valve finger tight.
54. Place the right side chain over the intake phaser and around the outside cogs of the idler sprocket so that the plate link of the chain is aligned with the machined circle on the sprocket.
55. With the chain aligned at the idler sprocket, install the intake camshaft phaser so that the machined lines are pointing towards each other and in a parallel line with the gasket surface of the cylinder head (see illustration 9.10b), then install the oil control valve finger tight.
56. Slide camshaft phaser lock tool #10202-1 from the front, between the two camshaft phasers, towards the chain (with the tool number facing up).
57. Using a large wrench on the camshaft flats and a socket and ratchet on the oil control valves, tighten both valves to the torque listed in this Chapter’s Specifications.
58. Install the oil pump timing chain, tensioner, sprocket and splash shield, if equipped (Oil pump – removal, inspection and installation).
Note: There are no timing marks on the oil pump chain or sprocket.
59. Verify all the marks are aligned (see illustration), then remove the special tool or Allen wrenches from the primary and secondary tensioners. Also remove the camshaft phaser lock tools.
8.59 Timing mark alignment details
1. Dimple on crankshaft
2. Junction of main bearing cap and cylinder block
3. Lines on right bank cam phasers – must be pointing toward each other and parallel with cylinder head
4. Arrows on right bank cam phasers – must be pointing away from each other
5. Arrows on left bank cam phasers – must be pointing toward each other
60. Rotate the engine two complete turns using the machined mark on the crankshaft with the line made where the engine block and bearing caps meet as the reference. Verify all the marks are aligned and there are 12 pins between the phaser marks (see illustration 8.17); if the marks are off, rotate the engine two more complete turns and check again.
61. Once the timing marks are correct, install the new coolant housing and water pump housing gaskets into the grooves on the back side of the timing chain cover.
62. Apply a 1/8-inch wide by 1/16-inch high, bead of RTV sealant to the sealing surface of the cover, then install the cover on the alignment dowels.
63. Install the cover bolts (see illustration 8.13) and tighten them in a criss-cross pattern, in three steps, to the torque listed in this Chapter’s Specifications.
64. The remainder of installation is the reverse of removal.
65. Add oil and coolant (see Tune-up and routine maintenance), start the engine and check for leaks