Write-Up: Replacing the Timing Chain on a '05 Terraza
 

Hello folks,


I just replaced the timing chain on a customer's '05 Terraza the other day so I'd like to post up the procedure for this job whilst it's still fresh in my mind ;)


1) Remove the timing chain cover by performing the following:

• Disconnect the negative battery cable.
• Drain the cooling system.
• Drain the engine oil.
• Remove the accessory drive belt.
• Remove the drive belt tensioner by accessing it through the wheelhouse opening.
• Remove the oil pan.
• Remove the crankshaft damper.
• Remove the thermostat bypass pipe from the timing chain cover.
• Remove the radiator output hose from the timing chain cover.
• Remove the water pump.
• Remove the power steering pump.
• Remove the (10) timing chain cover bolts.
• Remove the timing chain cover and gasket.

http://content.chiltonsonline.com/co...5-mont-g22.gif
**Shown here: Timing Chain Cover Bolts**


2) Once the cover is removed, rotate the crankshaft until the timing marks are aligned.

http://content.chiltonsonline.com/co...5-mont-g20.gif
**Shown here: Align the timing chain dampener (1) to the crankshaft sprocket (2) and the camshaft alignment pin (4) to the timing mark before removing**


3) Remove the camshaft sprocket bolt.

4) Remove the camshaft sprocket with the timing chain.

5) Remove the crankshaft sprocket.

6) Remove the timing chain dampener bolts and timing chain dampener.

7) If necessary, remove the camshaft thrust plate.


-Installation-


1) Clean and inspect the timing chain and gears.

2) If removed, install the camshaft thrust plate and tighten the bolts to 89 inch lbs. (10 Nm).

3) Install the crankshaft sprocket. Apply engine oil supplement (EOS) to the sprocket thrust surface.

4) Install the timing chain dampener and tighten to the bolts to 15 ft. lbs. (21 Nm).

5) Install the timing chain onto the camshaft gear. Hold the camshaft sprocket with the chain hanging down, and install the chain to the crankshaft gear.

6) Align the crankshaft timing mark (2) to the timing mark on the bottom of the timing chain dampener (1).

7) Align the timing mark on the camshaft gear, center line of the locator hole (4), with the timing mark on the top of the chain dampener (3).

8) Align the dowel in the camshaft with the dowel hole in the camshaft sprocket (1).

9) Install the camshaft sprocket bolt and tighten to 103 ft. lbs. (140 Nm).

10) Coat the crankshaft and camshaft sprocket with clean engine oil.

11) Install the timing chain cover. Refer to the timing chain cover diagram above:

• Install the timing chain cover bolts (1). Tighten the timing chain cover bolts to 20 ft. lbs. (27 Nm).
• Install the timing chain cover bolts (2,3). Tighten the timing chain cover bolts to 41 ft. lbs. (55 Nm).

12) Start the engine and check for leaks.

13) You're done ;) Stay tuned for most DIYs based off of some of the steps found in this write-up (i.e. water pump replacement)


--Additional timing chain diagram--

http://www.gmpartseast.com/diagrams/...gm00473u01.png
*diagram courtesy of gmpartsgiant.com; all rights reserved