GM 12646386 Chain Assembly, Timing

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To remove the timing chain cover, you need to first detach the negative cable from the battery and drain all the coolant. Afterwards, take out cooling fan, water pump, drive belt pulley and vibration damper. Then remove crankshaft position sensor and wiring harness nut. Remove oil pan then disconnect wiring harness clips from front cover. Remove crankshaft position sensor and camshaft position sensor with its jumper wiring harness. Afterward, remove the cover bolts and separate timing chain cover from block. Remove crankshaft position sensor reluctor ring and check timing chain free play. When needed replace the chain as well as sprockets. Be sure to align sprocket timing marks as well as release timing chain tensioner. To install timing chain cover clean engine block sealing surfaces then line up keyway on crankshaft sprocket. Press sprocket onto crankshaft while aligning balance shaft gears on opposite ends of shafts. Position crankshaft vis-à-vis camshaft sprocket in a way that allows passage of a looped chain over it. Apply thread locking compound onto camshaft sprocket bolt threads then tighten them up. Install crankshaft position sensor reluctor ring and apply RTV sealant to engine block sealing surface. Place new front cover and oil seal assembly in place plus tighten down on retaining bolts of cover afterward screws are tightened except for one at each end of upper edge of front plate where the attachment is made at an angle toward middle). Finally put back oil pan, vibration damper and then crankshaft position censor.

To remove an engine's timing chain, firstly disconnect the negative battery cable and drain the cooling system and engine oil. Next is to remove the water pump and crankshaft balancer then disconnect the wiring from the camshaft position sensor and camshaft position actuator magnet. After this, carefully unscrew the bolts of the timing chain cover without damaging it as well as remove an oil pump too. On engines without camshaft position actuators, loosen the camshaft sprocket bolts, rotate crankshaft until timing marks agree, then remove them along with chain as an assembly. For engines with camshaft position actuators though, turn the crankshaft such that timing marks are aligned hence removing solenoid valve and detaching actuator assembly and chain. Check if there is any wear or damage on timing chain tensioner, camshaft and crankshaft sprockets. If need be, disconnect sprocket from crankshaft. While reinstalling clean gasket surfaces and align Woodruff key with crankshaft sprocket. Take a new chain around camshaft sprocket meshing it into crankshaft sprocket. Make sure that timing marks are in line for engines having camshaft position actuators. Torque tighten fittingly either bolt of a camshaft sprocket or actuator valve compressing tensioner so as to hold it in place finally insert oil pump back into its housing. Finalize by cleaning out timing chain cover reattaching it securely using alignment tool placing a new crank shaft oil seal lastly performing reinstallation steps in reverse order after which fill up cooling system then do engine oil replacement together with changing oil filter checking for any engine leaks of coolant or oils.

During inspection, you should check the timing chain tensioner, camshaft, and crankshaft sprockets for wear or damage.

The final steps involve completing the reinstallation process in reverse order, filling the cooling system and engine oil, replacing the oil filter, and checking for any oil or coolant leaks during engine operation.

To remove the timing chain cover, you need to follow these steps:1. Disconnect the cable from the negative terminal of the battery.2. Drain the cooling system.3. Remove the cooling fan.4. Take off the water pump.5. Remove the drivebelt pulley.6. Remove the vibration damper.7. Remove the crankshaft position sensor and the wiring harness nut.8. Remove the oil pan.9. Disconnect the wiring harness clips from the front cover.10. Remove the crankshaft position sensor and the camshaft position sensor with its jumper wiring harness.11. Remove the cover bolts.12. Separate the timing chain cover from the block.13. Remove the crankshaft position sensor reluctor ring.14. Measure the timing chain free play.15. Replace the chain and sprockets if necessary.

To remove the timing chain cover, you need to follow these steps: 1. Disconnect the cable from the negative terminal of the battery. 2. Drain the cooling system. 3. Remove the cooling fan. 4. Take off the water pump. 5. Remove the drivebelt pulley. 6. Remove the vibration damper. 7. Remove the crankshaft position sensor and the wiring harness nut. 8. Remove the oil pan. 9. Disconnect the wiring harness clips from the front cover. 10. Remove the crankshaft position sensor and the camshaft position sensor with its jumper wiring harness. 11. Remove the cover bolts. 12. Separate the timing chain cover from the block. 13. Remove the crankshaft position sensor reluctor ring. 14. Measure the timing chain free play. 15. Replace the chain and sprockets if necessary.