GM 12703806
Camshaft

You must start by removing the Timing Chain then sprocket before you detach the valve lifters and balance shaft drive gear. Campshaft retainer bolts together with the retainer must be removed with extreme caution to protect the Camshaft bearings because every Camshaft journal shares the identical diameter. Use the holes in the engine Camshaft front where you installed three 5/16-18 x 4.0 inch bolts as a handle to gently pull the engine Camshaft out of the bearings leaving the bolt in place. After cleaning the Camshaft both parts should undergo examination. Engine oil replacement with new Oil Filter and gm engine oil supplement gm p/n 1052367 (Canadian P/N 992869) or equivalent supplement required before installing a new Camshaft. Clean engine oil gm p/n 12345610 (Canadian P/N 993193) or equivalent or engine oil supplement gm p/n 1052367 (Canadian P/N 992869) should be applied to the Camshaft lobes as well as bearing journals and bearings. You should use the three bolts as a tool to install the engine Camshaft before removing them. The threads of the Camshaft retainer bolts require a threadlock application from gm p/n 12345382 (Canadian P/N 10953489) when using existing fasteners. Sequence the installation by first putting on the Camshaft retainer and bolts before adding the balance shaft drive gear and valve lifters. Finish with the Timing Chain and Camshaft sprocket. Tighten all fasteners to 12 nm (106 inch lbs.).

The Camshaft replacement starts by removing the radiator support, engine front cover, valve lifters together with the Camshaft sensor bolt and sensor. Check the alignment of the timing marks between Crankshaft and Camshaft sprockets before rotating the engine until the Timing Chain comes out so you can protect the piston assemblies and valves from damage. Next remove the Camshaft sprocket and move the Timing Chain into position before installing the Camshaft retainer bolts together with the retainer where technicians need to exercise caution to protect the Camshaft bearings because all Camshaft journal dimensions are identical. Use three bolts with m8-1.25 x 100 mm size (M8-1.25 x 4.0 inch) to insert into the front holes of the Camshaft retaining plates before extracting it from the block by holding it as a lever. The Camshaft and its bearings need inspection for possible cleaning if necessary. Begin by applying engine oil to Camshaft journals and bearings and re-install the Camshaft into the engine block using the three previously used bolts and remove them afterward. Install the retainer plate so its sealing gasket faces the engine block and confirm that the gasket surface of the engine block remains clean. Install the Camshaft retainer along with bolts and tighten them to 25 nm before putting the Camshaft sprocket and position the Timing Chain. Finish by tightening Camshaft sprocket bolts to 35 nm. To proceed with installation it is necessary to check for damage on the Camshaft sensor o-ring seal. Once you find it intact apply clean engine oil and put the Camshaft sensor and bolt into position. Package this hardware assembly with a bolt torque setting at 25 nm (18 ft. Lbs.). Complete the installation sequence by putting in all valve lifters and the front cover and radiator support.

The Camshaft needs four procedural stages to exchange it: first remove the radiator support then the engine front cover with valve lifters and finally release the Camshaft sensor bolt and sensor. The engine should rotate for correct alignment of its Crankshaft and Camshaft sprocket timing marks while avoiding Crankshaft rotation once the Timing Chain is taken off to stop damage to piston assemblies and valves. Proceed by taking off the Camshaft sprocket then accurately place the Timing Chain before uninstalling the Camshaft retainer bolts and retainer. You should use caution when working on the Camshaft because each of its journals has equal diameters since this may result in bearing damage. Position three m8-1.25 x 100 mm (M8-1.25 x 4.0 inch) bolts into the front bolt holes of the Camshaft to use as pulling handles and extract it from the engine block before removing the bolts. Thorough cleaning and inspection should happen to the Camshaft along with its bearings. The installation procedure starts with engine oil lubrication of the Camshaft journals and bearings. After this the three m8-1.25 x 100 mm (M8-1.25 x 4.0-inch) bolts will be used to mount the Camshaft into the engine block and remove the bolts. Place the retainer plate into position with its sealing gasket directly against the engine block surface and maintain a debris-free gasket surface. Begin with tightening the Camshaft retainer bolts to 25 nm (18 ft. Lbs.), install the Camshaft sprocket and position the Timing Chain afterward. Ultimately tighten the Camshaft sprocket bolts to 35 nm (26 ft. Lbs.). If the Camshaft sensor o-ring remains undamaged you must lubricate it with clean engine oil before installing the sensor along with its bolt using 25 nm torque (18 ft lbs.) complete the installation with the valve lifters and then move on to front cover followed by radiator support.

The Camshaft replacement requires beginning with radiator support and engine front cover removal followed by removal of valve lifters. Start by unbolting the Camshaft sensor and sensor bolt then use the Crankshaft to align the timing marks of both the sprockets. Detach bolt number 206 from the Camshaft sprocket while keeping in mind the same diameter of all Camshaft journals to prevent bearing damage. Remove first the bolts (231) with Timing Chain Tensioner (232) from the assembly before taking out the Camshaft sprocket and moving the Timing Chain into position. Use a bolt as a handle to pull out the Camshaft carefully from the engine block after removing each retainer bolt (204) along with retainer (203). A detailed inspection as well as cleaning process should take place on both the Camshaft along with its bearings. After applying clean engine oil on Camshaft journals and bearings you should carefully reinstall the Camshaft into the engine block while removing the bolt. Put the Camshaft retainer (203) into place while its sealing gasket faces the engine block using a clean surface on the gasket. The first design hex head bolts require tightening to 25 nm (18 lb ft) while the second design torx(R) head bolts need 15 nm (11 lb ft). Hang the en 46330 onto the compressed Timing Chain Tensioner guide. Install the Timing Chain Tensioner (232) together with bolts (231) before tightening them to 25 nm (18 lb ft). The location pin of the Camshaft sprocket should match the alignment hole of the sprocket while ensuring proper alignment between the teeth. After sprocket marks of Camshaft and Crankshaft align correctly install the Camshaft sprocket (205) and Timing Chain (208). Begin by installing new Camshaft sprocket bolt (206) while following initial torque of 75 nm (55 lb ft) before applying a secondary 50 degrees of torque. The Camshaft sensor o-ring should be inspected for damage before using an unbroken one as replacement. To conclude the process install the valve lifters followed by the front cover and radiator support.

Use the three bolts as a handle to install the engine camshaft, then remove the bolts.

Remove the radiator support, valve lifters, engine front cover, and starter motor.

Next, remove the lifters, timing chain, and camshaft sprocket.

Change the engine oil and filter, add engine oil supplement, and lubricate the engine camshaft lobes, camshaft bearing journals, and camshaft bearings.

First, remove the radiator.

Install the camshaft into the engine block, followed by the balance shaft drive gear, timing chain, and camshaft sprocket.

Install three 5/16-18 x 4.0 inch bolts into the engine camshaft front bolt holes to use as a handle to rotate and pull the engine camshaft out of the camshaft bearings, then remove the bolts.

With the sealing gasket facing the engine block, keeping the gasket surface clean and free of debris.

Reinstall the engine camshaft using the bolts as a handle, then remove the bolts.

Clean and inspect the camshaft and bearings as necessary.

Install three 5/16-18 x 4.0 inch bolts into the front bolt holes and use them as a handle to rotate and pull the camshaft out.

Ensure the retainer plate is installed with the sealing gasket facing the engine block, keeping the gasket surface clean and free of debris, then install the camshaft retainer and bolts, tightening them to 25 Nm (18 ft. lbs.).

One M10-1.5 x 120 mm and one M10-1.5 x 45 mm bolt, tightened to 50 Nm (37 lb ft).