Chevrolet Cobalt Service & Repair Manual: Timing Chain, Replace
Caution: With the timing chain
removed, avoid turning the camshaft or crankshaft. If movement is required,
exercise extreme caution to avoid valve damage caused by piston contact. |
1. |
Disconnect and isolate battery ground
cable. |
2. |
Raise and support vehicle with jack
stands. |
3. |
Remove front fender liner. |
4. |
Turn drive belt tensioner clockwise. |
5. |
Remove serpentine drive belt. |
6. |
Remove crankshaft balancer bolt using
harmonic balancer holder GM tool No. J-38122-A, or equivalent, to
ensure crankshaft does not rotate while loosening mounting bolt. |
7. |
Remove crankshaft balancer. |
8. |
Remove engine front cover to water
pump bolts, Fig. 1. |
9. |
Remove remaining engine front cover
mounting bolts. |
10. |
Remove engine front cover gasket. |
11. |
Loosen vent hose clamp at air cleaner
resonator, air cleaner intake duct clamp at air cleaner outlet resonator. |
12. |
Loosen air cleaner outlet resonator
to throttle body clamp, located forward of accelerator cable bracket.
Remove air cleaner resonator to accelerator bracket bolt. |
13. |
Remove throttle body resonator, air
cleaner intake duct and vent hose. |
14. |
Disconnect accelerator and cruise control
cables from throttle body, then the bracket. |
16. |
Remove fuel line brackets and brake
booster hose pipe from brackets. |
17. |
Remove mounting screw, ignition coil
and Ignition Control Module (ICM). |
19. |
Remove mounting bolts and camshaft
cover. |
20. |
Turn engine until crankshaft sprocket
mark aligns with second silver link at five o'clock position. |
22. |
Ensure intake camshaft sprocket INT
diamond is aligned with copper link at two o'clock position,
Fig. 2. |
23. |
Ensure exhaust camshaft sprocket EXH
triangle is aligned with silver link at 10 o'clock position,
Fig. 3. |
24. |
Remove timing chain tensioner. |
25. |
Remove fixed timing chain guide access
plug. |
26. |
Remove fixed timing chain guide,
Fig. 4. |
27. |
Remove upper timing chain guide,
Fig. 5. |
28. |
Remove exhaust camshaft sprocket bolt
and camshaft sprocket using suitable 24 mm wrench to hold camshafts,
Fig. 6. |
29. |
Remove timing chain tensioner guide,
Fig. 7. |
30. |
Remove intake camshaft sprocket bolt,
intake camshaft sprocket and timing chain through top of cylinder
head, Fig. 8. |
31. |
Remove crankshaft sprocket, balance
shaft drive chain tensioner and adjustable balance shaft chain guide. |
32. |
Remove small balance shaft drive chain
guide. |
33. |
Remove upper balance shaft drive chain
guide, Fig. 9. |
34. |
Remove balance shaft drive chain,
Fig. 10. |
35. |
Install upper balance shaft chain guide. |
36. |
Install balance shaft drive chain with
colored links lined up on marks on balance shaft drive sprockets
and crankshaft sprocket, Fig. 11. |
37. |
Place copper link so it aligns with
intake side balance shaft sprocket timing mark. |
38. |
Move clockwise around chain, place
first chrome link inline with timing mark on crankshaft drive sprocket,
five o'clock position. |
39. |
Install chain on water pump drive sprocket. |
40. |
Align last chrome link with timing
mark on exhaust side balance shaft drive sprocket. |
41. |
Install small balance shaft chain guide. |
42. |
Tighten balance shaft chain guide bolts. |
43. |
Install adjustable balance shaft drive
chain guide. |
44. |
Turn tensioner plunger 90° in its
bore and compress plunger until paper clip can be inserted through
hole in plunger body and into hole in tensioner plunger, Fig.
12. |
45. |
Install timing chain tensioner. |
46. |
Remove paper clip from balance shaft
drive chain tensioner. |
47. |
Install crankshaft sprocket with timing
mark at five o'clock position, Fig. 13. |
48. |
Lower timing chain through opening
in top of cylinder head and ensure chain installs around both sides
of cylinder block bosses. |
49. |
Install intake camshaft sprocket with
INT diamond at two o'clock position, Fig. 2. |
50. |
Hand tighten new intake camshaft sprocket
bolt. |
51. |
Install timing chain around crankshaft
sprocket with second silver link aligning with timing mark. |
52. |
Install timing chain around intake
camshaft sprocket with copper link aligning with INT diamond. |
53. |
Install timing chain tensioner guide
through opening in top of cylinder head. |
54. |
Install exhaust camshaft sprocket with
timing chain silver link at EXH triangle aligned ten o'clock position,
Fig. 3. |
55. |
Install suitable 24 mm wrench to rotate
camshaft slightly, until exhaust sprocket aligns with camshaft. |
56. |
Hand tighten new exhaust camshaft sprocket
bolt. |
57. |
Install fixed timing chain guide. |
58. |
Apply sealant, GM part No. 12345382,
or equivalent, compound to thread and install timing chain guide
bolt access hole plug. |
59. |
Install timing chain upper guide. |
60. |
Measure timing chain tensioner when
fully compressed; tensioner will measure 2.83 inches. |
61. |
Install timing chain tensioner. |
62. |
Install suitable rubber tipped tool,
place tool down through camshaft drive to contact timing chain,
release tensioner using sharp contact downwards. |
63. |
Install suitable 24 mm wrench to hold
camshaft, Fig. 14. |
64. |
Torque mounting bolt to 63 ft.
lbs., then tighten an additional 30° turn. |
66. |
Raise and support vehicle with jack
stands. |
67. |
Install front engine cover. |
68. |
Torque front cover bolts to
18 ft. lbs. |
69. |
Torque crankshaft balancer bolt
to 74 ft. lbs., then tighten bolt an additional 125° turn. |
71. |
Install accessory drive belt. |
72. |
Inspect cooling system and fill to
proper level with recommended coolant, as required. |
73. |
Fill engine crankcase to proper level
with recommended engine oil. |
74. |
Connect battery ground cable. |
75. |
Start engine and confirm proper operation,
and ensure there are no leaks. |
76. |
Clear DTC(s) using a suitably programmed
scan tool. |
|
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Fig. 1 Engine front cover bolt replacement
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Fig. 2 Timing chain copper link alignment
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Fig. 3 Timing chain silver link alignment
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Fig. 4 Fixed timing chain guide replacement
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Fig. 5 Upper timing chain guide replacement
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Fig. 6 Exhaust camshaft bolt & sprocket replacement
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Fig. 7 Timing chain tensioner guide replacement
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Fig. 8 Camshaft bolt, sprocket & timing chain replacement
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Fig. 9 Upper balance shaft drive chain guide replacement
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Fig. 10 Balance shaft drive chain replacement
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Fig. 11 Timing chain installation
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Fig. 12 Tensioner plunger & body installation
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Fig. 13 Crankshaft sprocket timing mark
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Fig. 14 Camshaft tightening
1.
Disconnect the negative battery cable.
2.
Remove the camshaft cover.
3.
Remove the timing chain tensioner,
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Chevrolet Cobalt Owners Manual
Chevrolet Cobalt Service Manual