Cylinder Head Removal and Installation Part 1

The following new service information outlined in this bulletin will aid technicians in removal and installation of the cylinder head without the removal of the front engine cover. The new service procedure can be done in vehicle with the aid of a new General Motors special service tool part number EN-48464 - Lower Timing Gear Tensioner Holding Tool.

If the Lower Timing Gear Tensioner Holding Tool is not wedged correctly, the front cover will have to be removed to reset the timing chain tensioner.

The Lower Timing Gear Tensioner Holding Tool will wedge between the timing chain tensioner and the front cover center bolt. When wedged in place, this will allow the camshafts or cylinder head to be serviced or removed without the removal of the front cover to reset the timing chain tensioner.

It is very important to make sure when timing the engine that all your timing marks align; there is no margin for error. If timed incorrectly, damage to the engine may occur or a DTC P0017 may set (PCM uses the crankshaft position (CKP) sensor and the exhaust camshaft position (CMP) sensor information to monitor the correlation between the crankshaft and camshaft positions).

Tools Required

The following tools will be required to perform this new service procedure outlined in this bulletin:

EN-48464 - Lower Timing Gear Tensioner Holding Tool

EN-46547 - Flywheel Holding Tool (LK5 or L52 Engine Only)

J 44221 - Camshaft Holding Tool

J 45059 - Torque Angle Meter

TDC Indicator Tool (Some models may use a dial Indicator or graduation marks on the side of a sliding shaft for visual indication)

SI Documents

Before starting this new service procedure outlined in this bulletin, refer to the following SI documents and review. Print the SI documents with an asterisk (*) next to the document . The asterisk indicates additional service information shown in this bulletin.

Fuel Pressure Relief

Air Cleaner Resonator and Outlet Duct Replacement

Battery Replacement (LK5 or L52 Engine Only)

Evaporative Emission Hoses/Pipes Replacement - Engine

Lifting and Jacking the Vehicle

Draining and Filling Cooling System (Static Fill)

Draining and Filling Cooling System (Vac-N-Fill) *

Wheelhouse Panel Replacement (Front)

Cylinder Head Replacement *

Cylinder Head Disassemble *

Engine Coolant Temperature Sensor Replacement *

Valve Rocker Arm and Valve Lash Adjusters

Intake Camshaft Position Sensor Installation *

Exhaust Camshaft Position Sensor Installation *

Water Outlet Installation *

Camshaft Position Actuator Solenoid Valve Installation *

Cylinder Head Cleaning and Inspection

Camshafts Cleaning and Inspection

Camshaft Installation *

Camshaft Cover Cleaning and Inspection

Exhaust Manifold Replacement *

Intake Manifold Replacement *

Tire and Wheel Removal and Installation *

Oil Pan Skid Plate Replacement (LK5 or L52 Engine Only) *

Engine Shield Replacement (LK5 or L52 Engine Only) *

Oil Level Indicator and Tube Replacement Removal Procedure *

Engine Lift Bracket Replacement *

Power Steering Pump Replacement (LL8 Engine Only)

Drive Belt Replacement *

Generator Replacement *

Capacities - Approximate Fluid *

Engine Cylinder Head Removal

Install protective covering to the front of the vehicle. This is to protect the grille from damage.

Install fender covers.

Bleed the fuel pressure. Refer to Fuel Pressure Relief in SI.

Remove the air cleaner resonator, the outlet duct and the air cleaner assembly.

Refer to Air Cleaner Resonator and Outlet Duct Replacement Removal Procedure in SI.

Refer to Air Cleaner Assembly Replacement in SI. Disconnect the negative battery cable (LL8 Engine Only).

Remove the battery from the vehicle. Refer to Battery Replacement in SI (LK5 or L52 Engine Only).

Disconnect the Fuel/EVAP lines from the intake manifold and move aside (includes fuel line removal from fuel rail). Refer to Evaporative Emission Hoses/Pipes Replacement - Engine in SI.

Remove the bolt holding the oil indicator (dipstick) tube to the intake manifold and move the oil dipstick aside (Do not remove).

Drain the engine coolant. Refer to Draining and Filling Cooling System (Static Fill) in SI.

Lift the Vehicle. Refer to Lifting and Jacking the Vehicle in SI.

Remove the bolts holding the engine shield (LK5 or L52 Engine Only).

Remove the engine shield from the vehicle (LK5 or L52 Engine Only.

Remove the bolts holding the oil pan skid plate (LK5 or L52 Engine Only).

Remove the oil pan skid plate from the vehicle (LK5 or L52 Engine Only).

Remove the drive belt.

Drain the engine oil.

Remove left front tire and wheel.

Remove the left front wheelhouse panel. Refer to Wheelhouse Panel Replacement (Front) in SI.

Remove the fir tree wiring harness connectors from the engine wring harness bracket from the left front wheelhouse opening.

From the left front wheelhouse, remove the engine wiring harness bracket from the engine and set aside. It may be necessary to loosen the fasteners on the frame rail (LL8 Only).

Remove the intake manifold bolts from the wheelhouse access (bolts stay with intake manifold). On two-wheel drive vehicles, the intake manifold bolts are removed from the top of the engine, not through the left front wheelhouse panel.

Lower the vehicle.

Remove the PCV pipes from the cam cover and remove the intake manifold from the vehicle.

Remove the PCM engine harness connectors from the PCM (LL8 Engine Only).

Remove the PCM from the intake manifold bracket (LL8 Engine Only).

Remove the generator output BAT terminal nut.

Remove the generator lead from the generator.

Disconnect the generator electrical connector.

Remove the generator bolts and set the generator aside. The generator does not have to be removed from the vehicle. On a two-wheel drive vehicle, the generator must be removed from the vehicle.

Remove the generator (LL8 Engine Only).

Disconnect the A/C pipe clamp from the engine lift hook bracket.

Remove the engine lift hook bracket bolts and bracket from the vehicle.

Remove the P/S pump bolts and reposition the pump (LL8 Engine Only).

Remove the bolts holding the windshield washer solvent container and coolant recovery reservoir to the right inner fender. Move aside to gain access to the engine wiring harness to PCM (LK5 or L52 Engine Only).

Disconnect the following cross-vehicle engine wiring harness connectors:

PCM

Engine Coolant Temperature Sensor

MAP Sensor

Ignition Coils

Harness clamps at power steering pump

Wiring Harness fastener at right front inner fender

Throttle Body

Camshaft Sensors

Exhaust Camshaft Actuator

Fuel Injectors

HO2S # 1

Set aside the cross-vehicle engine wiring harness on the left side of the vehicle.

Remove the A.I.R. injection pipe block-off plate bolts from the cylinder head.

Remove the A.I.R. injection pipe block-off plate.

Remove the bolts from the exhaust manifold heat shield.

Remove the exhaust manifold heat shield.

Remove the exhaust manifold bolts.

Move the exhaust manifold back and away from the cylinder head.

Remove the bolts to all ignition coil assemblies and remove all ignition coil assemblies from the cam cover.

Remove all the spark plugs from the cylinder head.

Remove ground strap bolt (LL8 Engine Only).

Remove the cam cover bolts.

Remove the cam cover from the cylinder head.

Remove the upper radiator hose and clamp from the cylinder head.

Before performing the TDC procedures, break loose both the exhaust and intake camshaft sprocket bolts. Use a 25 mm (1 in) open end wrench on the camshaft hexs to hold the camshaft from turning. Do Not remove the bolts. Refer to the above illustration.

Perform the following service timing procedure:

View A

View B

View C

Rotate the engine clockwise by hand to TDC on the compression stroke by using a piston TDC indicator tool and/or dial indicator in the number 1 cylinder. Refer to the above illustrations View A and View B. The TDC indicator tool graduation marks on the shaft should note top of the piston stroke. When the piston is at TDC, the flats at the rear of the camshafts will be facing up and flat when using a straight edge across the camshaft flats. There may be a variation of build and the straight edge may not lay perfectly flat across back of the camshafts. Refer to the above illustration VIEW C

Do not rotate the engine counterclockwise to find TDC, as this will put slack in the camshaft actuator and the timing chain. If the engine is rotated counterclockwise, even a small amount, then the engine should be rotated at least 90 degrees and then brought back to TDC by rotating clockwise only.

The word Delphi on the exhaust camshaft position actuator will be parallel with the cylinder head to cam cover mating surface. When the piston is at TDC, the flats at the rear of the camshafts will be facing up.

Once TDC is located for the number 1 cylinder using above method, raise the vehicle and lock the flywheel with tool EN-46547 - Flywheel Holding Tool (LK5 or L52 Engine Only). Refer to the above illustration.

Use a metal scribe or equivalent to place a reference mark on the harmonic balancer to the front cover for alignment purposes (White Paint Pen is for demonstration purposes only). Refer to above illustration.

Lower the vehicle.

The camshaft holding tools must be installed on the camshafts to prevent camshaft rotation. When performing service to the valve train and/or timing components, valve spring pressure can cause the camshafts to rotate unexpectedly and can cause personal injury.

If the timing is correct (TDC compression stroke number 1 cylinder), the camshaft flats will be in the up position.

Install the J 44221 - Camshaft Holding Tool to the back of the camshafts.
Refer to the above illustration.

Remove the upper timing chain guide from the cylinder head (not found on later vehicles).

The exhaust camshaft actuator must be fully advanced before scribing your reference mark on both timing gear sprockets and the timing chain to mark location prior to disassembly. There may be some normal play in the exhaust camshaft actuator itself. To ensure camshaft actuator is fully advanced, do not rotate engine counterclockwise when finding TDC # 1.

Clean the timing chain and gears with Brake Cleaner or suitable solvent. Use a metal scribe or equivalent to place a reference mark on both timing gear sprockets and the timing chain to mark the location prior to disassembly. It is recommended that a metal scribe or equivalent be in the 12:00 position (White Paint Pen for demonstration purposes only). Refer to the illustration.

View B

Illustration View B shows the front cover removed for demonstration purposes only.

Do NOT use excessive force to seat the wedge tool. If excessive force is used, you may damage the timing chain tensioner or break the front cover bolt requiring complete disassembly of the front engine.

View A

View C

Install EN-48464 - Lower Timing Chain Tensioner Holding Tool per the above illustration View A. This wedge tool will hold the timing chain and tensioner in position. It is important to install the tool with the proper orientation and to ensure that it is seated square against the timing chain and against the timing cover center bolt. The narrow ramp of the wedge tool needs to be placed so that it faces the timing chain. Refer to the above illustration View B. The wedge tool should be lightly seated using a couple of very light taps with a small plastic or brass hammer. Refer to the above illustration View C.

The illustration shows the front cover removed for demonstration purposes only.

Once the tool is correctly installed, unscrew the handle and remove the handle. Refer to the above illustration.

Remove (1 long and 2 short) cylinder head bolts next to the exhaust and intake timing chain tensioner shoes and discard the bolts.

Use a 25 mm (1 in) open end wrench on the camshaft hexs to hold the camshaft from turning. It is critical that the crankshaft does not move and is held at TDC when the intake and exhaust camshaft sprocket bolts are removed.

If the crankshaft is not held in place, the wedge tool could be dislodged. If the crankshaft moves, or if the tool is not seated properly allowing the timing chain tensioner to extend, the repair will have to be completed by removing the front cover to release the timing chain tensioner.

Remove both upper cylinder head access hole plugs from the front of the cylinder head.

Remove both upper timing chain tensioner shoe bolts.

Remove the exhaust and the intake camshaft sprocket bolts. Discard the bolts.

Carefully remove the exhaust and intake camshaft sprockets from the exhaust and intake camshafts while still engaged with the timing chain. Refer to the above illustration. The above illustration shows the exhaust camshaft sprocket already removed.

Remove the sprockets from the chain. Tie a piece of mechanics wire on the timing chain and let it drop. Refer to the above illustration.

Remove the cylinder head bolts from the cylinder head. Before removing the cylinder head bolts, use a drift punch and hammer to shock the bolts. This will ensure that the cylinder head bolts will not strip out the threads in the engine block or break. Once the bolts are removed, discard them. Refer to the above illustration.

Remove the AIR pump bolt and fir tree fastener from the back of the cylinder head. Refer to Service Bulletin 06-06-04-016A for further information.

Remove the cylinder head from the vehicle.

Disassemble the cylinder head. Refer to SI for the following cylinder head procedures:

Cylinder Head Disassemble. The following components will have to be removed when disassembling the cylinder head. Refer to SI for the following service procedures:

Engine Coolant Temperature Sensor Replacement

Intake Camshaft Position Sensor Removal/Installation

Exhaust Camshaft Sensor Removal/Installation

Camshaft Position Actuator Solenoid Valve Removal/Installation

Water Outlet Removal/Installation

Valve Rocker Arm and Valve Lash Adjusters Removal/Installation

Cylinder Head Cleaning and Inspection

Cylinder Head Assembly. Refer to the above service procedure for assembly.
Engine Cylinder Head Installation

A new service cylinder head assembly with valves is available for L52 only.

Install the cylinder head without the camshafts.

Install the engine cylinder head to the engine block.

Install the AIR pump bolt and fir tree fastener from the back of the cylinder head. Refer to Service Bulletin 06-06-04-016A for further information.

Install new cylinder head bolts and tighten the bolts. Refer to Cylinder Head Replacement in SI.