Timing Chain: Service and Repair

Timing Chain, Sprockets, and/or Tensioner Replacement

^ Tools Required
- J 45027 Tensioner Tool
- J 45059 Angle Meter

Removal Procedure

Important: The timing chain has 2 matching colored links and 1 uniquely colored link.





1. Remove the camshaft cover.
2. Remove the engine front cover.
3. Rotate the engine until the crankshaft sprocket mark aligns with the matching colored link (2) at the 5 o'clock position.
4. Lower the vehicle.





5. Ensure that the timing mark (4) on the intake camshaft sprocket is aligned with the blue colored link (1) at the 2 o'clock position.





6. Ensure that the timing mark (3) on the exhaust camshaft sprocket is aligned with the pink colored link.





7. Remove the timing chain tensioner.





8. Remove the fixed timing chain guide access plug.





9. Remove the fixed timing chain guide bolts and guide.





10. Remove the upper timing chain guide bolts and guide.
11. Using a 24-mm wrench, hold the camshaft in order to prevent the camshaft from turning.





12. Remove and discard the exhaust camshaft sprocket bolt (2).
13. Remove the exhaust camshaft sprocket (1).





14. Remove the timing chain tensioner guide bolt and guide.





15. Remove and discard the intake camshaft sprocket bolt (2).
16. Remove the intake camshaft sprocket (3).
17. Remove the timing chain out through the top of the cylinder head.





18. Remove the crankshaft sprocket.





19. Remove the balance shaft drive chain tensioner bolts and tensioner.





20. Remove the adjustable balance shaft chain guide bolt and guide.





21. Remove the small balance shaft drive chain guide bolts and guide.





22. Remove the upper balance shaft drive chain guide bolts and guide.





23. Important: The balance shaft drive chain will be easier to remove if you gather all of the slack in the chain between the crankshaft and water pump sprockets.

Remove the balance shaft drive chain.

Installation Procedure





1. Install the timing chain drive sprocket to the crankshaft with the timing mark in the 5 o'clock position.





2. Important:
^ There are 3 colored links on the timing chain. Two links are of matching color and one link is of a unique color. Use the following procedure to line up the links with the sprockets. Orient the chain so that the colored links are visible.
^ Always use NEW sprocket bolts.

Assemble the intake camshaft sprocket (3) to the timing chain with the timing mark (4) lined up with the blue colored link (1). Install and hand tighten a NEW intake camshaft sprocket bolt (2).





3. Lower the timing chain through the opening in the cylinder head. Use care to ensure that the chain goes around both sides of the cylinder block bosses (1, 2).





4. Route the timing chain around the crankshaft sprocket and line up the first matching colored link (2) with the timing mark on the crankshaft sprocket, in approximately the 5 o'clock position.





5. Notice: Refer to Fastener Notice.

Install the adjustable timing chain guide through the opening in the cylinder head. Install the adjustable timing chain bolt.
Tighten the bolt to 10 Nm (89 inch lbs.).





6. Important: Always install NEW sprocket bolts.

Install the exhaust camshaft sprocket (1) and a NEW bolt (2) loosely onto the exhaust camshaft.
7. Align the timing mark (3) on the sprocket with the last matching colored link. Tighten the bolt finger tight.

8. Important: Do not rotate the camshaft more than 1/2 turn in either direction. Doing so may cause valve-to-piston contact. This may damage a valve and/or a piston. If the camshaft is 180 degrees out of time, use the following procedure to re-align the cam.

Using a 24-mm wrench, turn the intake camshaft until the alignment feature on the back of the camshaft sprocket seats in the notch in the front of the intake camshaft.
1 Turn the crankshaft 45 degrees in either direction.
2 Turn the intake cam to the appropriate location.
3 Turn the crankshaft back to top dead center.
9. When the sprocket seats on the cam, tighten the sprocket bolt hand tight.
10. Verify that all of the colored links and the appropriate timing marks are still aligned. If they are not, repeat the portion of the procedure necessary to align the timing marks.





11. Install the fixed timing chain guide and bolts.
Tighten the bolts to 10 Nm (89 inch lbs.).





12. Install the upper timing chain guide and bolts.
Tighten the bolts to 10 Nm (89 inch lbs.).
13. Using a 24-mm wrench, engage the hex on the intake camshaft. Using a torque wrench, tighten the camshaft sprocket bolt.
Tighten the bolt to 85 Nm (63 ft. lbs.), plus 30 degrees using the J 45059.
14. Using a 24-mm wrench, engage the hex on the exhaust camshaft. Using a torque wrench, tighten the camshaft sprocket bolt.
Tighten the bolt to 85 Nm (63 ft. lbs.), plus 30 degrees using the J 45059.





15. Remove the old oil from the timing chain tensioner.
16. Inspect the timing chain tensioner for scoring or free movement.
17. Inspect the timing chain washer and O-ring for damage. If damaged, replace the timing chain tensioner.
18. Measure the timing chain tensioner assembly from end to end. A NEW tensioner should be supplied in the fully compressed non-active state. A tensioner in the compressed state will measure 72 mm (2.83 inch) (a) from end to end. A tensioner in the active state will measure 85 mm (3.35 inch) (a) from end to end.





19. If the timing chain tensioner is not in the compressed state, perform the following steps:
0 Remove the piston assembly from the body of the timing chain tensioner by pulling it out.
1 Install the J 45027-2 (2) into a vise.
2 Install the notch end of the piston assembly into the J 45027-2 (2).
3 Using the J 45027-1 (1), turn the ratchet cylinder into the piston.





20. Inspect the bore of the tensioner body for dirt, debris, and damage. If any damage appears, replace the tensioner. Clean dirt or debris with a lint free cloth.
21. Install the compressed piston assembly back into the timing chain tensioner body until the assembly stops at the bottom of the bore. Do not compress the piston assembly against the bottom of the bore. If the piston assembly is compressed against the bottom of the bore, the assembly will activate the tensioner, which will then need to be reset again.
22. At this point the tensioner should measure approximately 72 mm (2.83 inch) (a) from end to end. If the tensioner does not read 72 mm (2.83 inch) (a) from end, to end repeat steps 19.1 - 19.4.





23. Ensure that all dirt and debris are removed from the timing chain tensioner threaded hole in the cylinder head.
24. Install the timing chain tensioner.
Tighten the tensioner to 75 Nm (66 ft. lbs.).
25. The timing chain tensioner is released by compressing the tensioner 2 mm (0.079 inch) which will release the locking mechanism in the ratchet. To release the timing chain tensioner, use a suitable tool with a rubber tip on the end. Feed the tool down through the cam drive chest to rest on the cam chain. Then give a sharp jolt diagonally downwards to release the tensioner.





26. Ensure that all dirt and debris are removed from the timing chain oiling nozzle hole in the engine block.
27. Install the timing chain oiling nozzle and bolt.
Tighten the bolt to 10 Nm (89 inch lbs.).





28. Apply sealant GM PN 12345382 (Canadian PN 10953489) or equivalent, to the threads and install the timing chain guide bolt access hole plug.
Tighten the plug to 90 Nm (59 ft. lbs.).
29. Install the engine front cover.
30. Install the camshaft cover.