Engine Mechanical - 3.5L: Diagnosis Saturn Aura I

Diagnostic Starting Point - Engine Mechanical

Begin the system diagnosis by reviewing the Disassembled Views , Engine Component Description , Drive Belt System Description and Lubrication Description . Reviewing the description and operation information will help you determine the correct symptom diagnostic procedure when a malfunction exists. Reviewing the description and operation information will also help you determine if the condition described by the customer is normal operation. Refer to Symptoms - Engine Mechanical in order to identify the correct procedure for diagnosing the system and where the procedure is located.

Strategy Based Diagnostics

1. Perform A Diagnostic System Check in Engine Controls before using the symptom tables-if applicable.
2. Review the system operations in order to familiarize yourself with the system functions. Refer to «Disassembled Views»(ref-301513-S20466232942008101700000) , «Engine Component Description»(ref-301513-S41137797652008101700000) , «Drive Belt System Description»(ref-301513-S09532946002008101700000) and «Lubrication Description»(ref-301513-S32193098262008101700000) .

All diagnosis on a vehicle should follow a logical process. Strategy based diagnostics is a uniform approach for repairing all systems. The diagnostic flow may always be used in order to resolve a system problem. The diagnostic flow is the place to start when repairs are necessary. For a detailed explanation, refer to Strategy Based Diagnosis .

Visual/Physical Inspection

1. Inspect for aftermarket devices which could affect the operation of the Engine. Refer to «Checking Aftermarket Accessories»(ref-301517-S04233661632008101700000) .
2. Inspect the easily accessible or visible system components for obvious damage or conditions which could cause the symptom.
3. Check for the correct oil level, proper oil viscosity, and correct filter application.
4. Verify the exact operating conditions under which the concern exists. Note factors such as engine RPM, ambient temperature, engine temperature, amount of engine warm-up time, and other specifics.
5. Compare the engine sounds-if applicable to a known good engine and make sure you are not trying to correct a normal condition.

Symptom List

Refer to a symptom diagnostic procedure from the following list in order to diagnose the symptom

1. «Base Engine Misfire without Internal Engine Noises»(ref-301513-S13758457282008101700000)
2. «Base Engine Misfire with Abnormal Internal Lower Engine Noises»(ref-301513-S42038087312008101700000)
3. «Base Engine Misfire with Abnormal Valve Train Noise»(ref-301513-S36378917772008101700000)
4. «Base Engine Misfire with Coolant Consumption»(ref-301513-S16447411302008101700000)
5. «Base Engine Misfire with Excessive Oil Consumption»(ref-301513-S24806989302008101700000)
6. «Engine Compression Test»(ref-301513-S22624474242008101700000)
7. «Engine Noise on Start-Up, but Only Lasting a Few Seconds»(ref-301513-S20780078182008101700000)
8. «Upper Engine Noise, Regardless of Engine Speed»(ref-301513-S16738885062008101700000)
9. «Lower Engine Noise, Regardless of Engine Speed»(ref-301513-S33515402082008101700000)
10. «Engine Noise Under Load»(ref-301513-S13368379932008101700000)
11. «Engine Will Not Crank - Crankshaft Will Not Rotate»(ref-301513-S26148658632008101700000)
12. «Oil Consumption Diagnosis»(ref-301513-S20709647292008101700000)
13. «Oil Pressure Diagnosis and Testing»(ref-301513-S16983607822008101700000)
14. «Oil Leak Diagnosis»(ref-301513-S06946417382008101700000)
15. «Drive Belt Chirping, Squeal, and Whine Diagnosis»(ref-301513-S28130158512008101700000)
16. «Drive Belt Rumbling and Vibration Diagnosis»(ref-301513-S06329998082008101700000)
17. «Drive Belt Falls Off and Excessive Wear Diagnosis»(ref-301513-S26990937752008101700000)
18. «Valve Rocker Arm Cover Replacement - Right Side»(ref-301513-S04523699782008101700000)
19. «Drive Belt Tensioner Diagnosis»(ref-301513-S39047113742008101700000)

Oil Consumption Diagnosis

An engine that has excessive oil consumption uses 0.9 L (1 qt) of oil, or more, within 3 200 km (2,000 mi). The following list indicates the conditions and corrections of excessive oil consumption

1. An improperly read oil level indicator dipstick Inspect the oil level while the vehicle is parked on a level surface. Allow adequate drain-down time.
2. Improper oil viscosity Use the recommended SAE viscosity for prevailing temperatures.
3. Continuous high-speed driving
4. Severe hauling, such as a trailer. This causes decreased oil mileage.
5. A malfunctioning crankcase ventilation system
6. External oil leaks Tighten the bolts, as needed. Replace the gaskets and seals, as needed.
7. Worn or omitted valve guides and/or valve stem seals Ream the guides. Install oversized service valves and/or new valve stem seals.
8. Broken or worn piston rings
9. Improperly installed or unseated piston rings
10. Improperly installed or improperly fitted piston
11. Plugged cylinder head gasket oil drain holes
12. Damaged intake gaskets

Oil Pressure Testing

Tools Required

1. J-21867-6 Oil Pressure Adapter Fitting. See «Special Tools»(ref-301513-S24222073032008101700000) .
2. J 25087-C Oil Pressure Tester and Pump Primer. See «Special Tools»(ref-301513-S24222073032008101700000) .

If the vehicle has low oil pressure complete the following steps

1. Inspect the oil level.
2. Raise and support the vehicle. Refer to «Lifting and Jacking the Vehicle»(ref-301499-S33480567202008101700000) .
3. Remove the oil filter.
4. Assemble the plunger valve in the large hole of the J 25087-C base. See «Special Tools»(ref-301513-S24222073032008101700000) . Insert the hose in the small hole of the J 25087-C base. See «Special Tools»(ref-301513-S24222073032008101700000) . Connect the gage to the end of the hose.
5. Insert the flat side of the rubber plug in the bypass valve without depressing the bypass valve.
6. Install the J 25087-C and J-21867-6 on the filter mounting pad. See «Special Tools»(ref-301513-S24222073032008101700000) .
7. Start the engine.
8. Inspect the overall oil pressure, the oil pressure switch, and for noisy lifters. Ensure that the engine is at operating temperature before inspecting the oil pressure. Refer to «Engine Mechanical Specifications»(ref-301513-S30806232122008101700000) for proper oil pressure specifications.
9. If adequate oil pressure is indicated, test the oil pressure switch.
10. If a low reading is indicated, press the valve on the tester base in order to isolate the oil pump and/or its components from the lubricating system. An adequate reading at this time indicates a good pump and the previous low pressure was due to worn bearings, etc. A low reading while pressing the valve indicates a faulty pump.

Visual Inspection Method

Complete the following steps in order to perform the visual inspection method

1. Bring the vehicle to normal operating temperature.
2. Park the vehicle over a large sheet of paper, or other clean surface.
3. Wait several minutes, then inspect for dripping fluids.
4. Identify the type of fluid, and the approximate location of the leak.
5. Visually inspect the suspected area. Use a small mirror if necessary.
6. Inspect for leaks at sealing surfaces, fittings, or from cracked or damaged components.
7. If you cannot locate the leak, perform the following steps: Completely clean the entire engine and surrounding components. Operate the vehicle for several miles at normal operation temperature and at varying speeds. Park the vehicle over a large sheet of paper, or other clean surface. Wait several minutes, then inspect for dripping fluids. Identify the type of fluid, and the approximate location of the leak. Visually inspect the suspected area. Use a small mirror if necessary.
8. If you still cannot locate the leak, use the powder method or the black light and dye method.

Diagnostic Aids

1. A chirping or squeal noise may be intermittent due to moisture on the drive belts or the pulleys. It may be necessary to spray a small amount of water on the drive belts in order to duplicate the customers concern. If spraying water on the drive belt duplicates the symptom, cleaning the belt pulleys may be the probable solution.
2. If the noise is intermittent, verify the accessory drive components by varying their loads making sure they are operated to their maximum capacity. An overcharged A/C system, power steering system with a pinched hose or wrong fluid, or a generator failing are suggested items to inspect.
3. A chirping, squeal or whine noise may be caused by a loose or improper installation of a body or suspension component. Other items of the vehicle may also cause the noise.
4. The drive belts will not cause a whine noise.

The accessory drive components can have an affect on engine vibration. Vibration from the engine operating may cause a body component or another part of the vehicle to make rumbling noise. Vibration can be caused by, but not limited to the A/C system over charged, the power steering system restricted or the incorrect fluid, or an extra load on the generator. To help identify an intermittent or an improper condition, vary the loads on the accessory drive components.

The drive belt may have a rumbling condition that can not be seen or felt. Sometimes replacing the drive belt may be the only repair for the symptom.

If replacing the drive belt, completing the diagnostic table, and the noise is only heard when the drive belts are installed, there might be an accessory drive component with a failure. Varying the load on the different accessory drive components may aid in identifying which component is causing the rumbling noise.

If the drive belt repeatedly falls off the drive belt pulleys, this is because of pulley misalignment.

An extra load that is quickly applied on released by an accessory drive component may cause the drive belt to fall off the pulleys. Verify the accessory drive components operate properly.

If the drive belt is the incorrect length, the drive belt tensioner may not keep the proper tension on the drive belt.

Excessive wear on a drive belt is usually caused by an incorrect installation or the wrong drive belt for the application.

Minor misalignment of the drive belt pulleys will not cause excessive wear, but will probably cause the drive belt to make a noise or to fall off.

Excessive misalignment of the drive belt pulleys will cause excessive wear but may also make the drive belt fall off.

Drive Belt Tensioner Diagnosis

Engine Mount Inspection

1. Install the engine support fixture. Refer to «Engine Support Fixture»(ref-301513-S13537661392008101700000) .
2. Observe the engine mount while raising the engine. Raising the engine removes the weight from the engine mount and creates slight tension on the rubber.
3. Replace the engine mount if the engine mount exhibits any of the following conditions: The hard rubber is covered with heat check cracks. The rubber is separated from the metal plate of the engine mount. The rubber is split through the center of the engine mount. The engine mount itself is leaking fluid.
4. For engine mount replacement. Refer to «Engine Mount Replacement»(ref-301513-S38167725912008101700000) .

Engine Block Cleaning and Inspection

Tools Required

1. J 8001 Dial Indicator Set. See «Special Tools»(ref-301513-S24222073032008101700000) .
2. J 8087 Cylinder Bore Gage

Cleaning and Inspection

1. Clean the sealing material from the gasket mating surfaces.
2. Boil the engine block in caustic solution.
3. Flush the engine block with clean water or steam.
4. Clean the oil passages.
5. Clean the blind holes.
6. Spray the cylinder bores and the machined surfaces with engine oil.
7. Inspect the threaded holes.
8. Clean the holes with a tap. Drill out the holes and install thread inserts, as needed.
9. Use a straight edge and a feeler gauge in order to test the deck surface for flatness. Replace the block if it is outside of the specification limit.
10. Inspect the oil pan rail for nicks.
11. Inspect the front cover attaching area for nicks. Use a flat mill file in order to remove any nicks.
12. Inspect the mating surfaces of the transmission case.
13. Use the following procedure in order to measure the engine block flange runout at the 6 mounting bolt hole bosses: Temporarily install the crankshaft. Measure the crankshaft flange runout. Hold the J 8001 gage plate flat against the crankshaft flange. See «Special Tools»(ref-301513-S24222073032008101700000) . Place the dial indicator stem on the transmission mounting bolt hole boss. Set the indicator to 0. Record the readings obtained from all of the bolt hole bosses. The measurements should not vary more than 0.25 mm (0.010 in). Retest the crankshaft flange runout if the readings vary more than 0.25 mm (0.010 in). If the crankshaft flange runout is not within the specification, replace the engine block.
14. Inspect the crankshaft main bearing bores. Use the J 8087 in order to measure the bearing bore concentricity and alignment at the following locations: The camshaft The crankshaft
15. Replace the engine block if the bores are out of specification.
16. Use the J 8087 in order to inspect the cylinder bores. Inspect the bores for the following conditions: Wear Taper Runout Ridging
17. Leave sufficient material in order to allow honing when fitting the piston.

Piston Oil Nozzle Cleaning and Inspection

1. Clean the piston oil nozzle in cleaning solvent using GM P/N 10953463 (Canadian P/N 88901148) or equivalent.
2. Dry the nozzle with compressed air.
3. Inspect the piston oil nozzle for the following: For cracks or damage Plugged oil passages (1) Bent, misaligned, or cracked oil nozzle tubes (2) Bent or broken clip (3)

Crankshaft and Bearing Cleaning and Inspection

Tools Required

1. J 8087 Cylinder Bore Gage
2. J 45059 Angle Meter

1. Clean the crankshaft of the following elements: Oil Sludge Carbon
2. Inspect the crankshaft oil passages for obstructions.
3. Inspect the crankshaft keyway for the following conditions: A worn crankshaft key (1) A worn crankshaft keyway (2)
4. Inspect the crankshaft threads (3) for damage.
5. Inspect the crankshaft bearing journals and the crankshaft thrust surfaces for the following conditions: Wear without any grooves or scratches (1) Grooves or scoring (2) Scratches or excessive wear (3) Pitting or embedded bearing material (4)-Inspect the corresponding crankshaft bearing inserts for embedded material and determine the source of the material. Overheating or discoloration
6. The crankshaft bearings are the precision insert type.
7. Inspect the outer surfaces of the crankshaft bearings for the following conditions: Wear-surface wear indicates either movement of the insert, or high spots in the surrounding material - spot wear. Overheating or discoloration Looseness or rotation indicated by flattened tangs and wear grooves
8. Inspect the crankshaft main bearings for craters or pockets. Flattened sections on the crankshaft bearing halves also indicate fatigue.
9. Inspect the thrust surfaces of the main thrust bearing for the following conditions: Wear Grooving-Grooves are caused by irregularities of the crankshaft thrust surface.
10. Inspect the crankshaft bearings for excessive scoring or discoloration.
11. Inspect the crankshaft main bearings for dirt or imbedded debris.
12. Inspect the crankshaft main bearings for improper seating indicated by bright, polished sections.
13. Inspect the crankshaft bearings for uneven side-to-side wear. This may indicate a bent crankshaft or a tapered bearing journal.
14. Inspect the connecting rod bearing bores or crankshaft main bearing bores using the following procedure: Tighten the bearing cap to specification. Use the J 8087 in order to measure the bearing bore for taper and out-of-round. Record the readings for bearing selection. No taper or out-of-round should exist.

Crankshaft Balancer Cleaning and Inspection

1. Clean the crankshaft balancer in solvent.
2. Clean the belt grooves of all dirt or debris with a wire brush.
3. Inspect the crankshaft balancer for the following: IMPORTANT: A crankshaft balancer hub seal surface with excessive scoring, grooves, rust or other damage must be replaced. Minor imperfections on the hub seal surface may be removed with polishing compound or fine grade emery cloth. Worn, grooved, or damaged hub seal surface IMPORTANT: In order for the belt to track properly, the belt grooves should be free of all dirt, debris, nicks, gouges or other damage. Minor imperfections may be removed with a fine file. Dirty or damaged belt grooves. Worn, chunking or deteriorated rubber between the hub and pulley

Engine Flywheel Cleaning and Inspection

1. Clean the engine flywheel with solvent.
2. Dry the engine flywheel with compressed air.
3. Inspect the engine flywheel for the following: Damaged ring gear teeth Stress cracks around the flywheel-to-crankshaft bolt hole locations

Piston, Connecting Rod, and Bearing Cleaning and Inspection

Tools Required

1. J 8087 Cylinder Bore Gage
2. EN-46745 Piston Pin Retainer Remover and Installer

1. Clean the piston and connecting rod in solvent.
2. Dry off the piston and connecting rod with compressed air.
3. Clean the piston ring grooves with a suitable ring groove cleaning tool.
4. Clean the piston oil lubrication holes and slots.
5. Inspect the piston for the following: Eroded areas (1) on the top of the piston Scuffed or damaged skirt (2) Damage to the pin bore (3) Cracks in the piston ring lands, the piston skirt, or the pin bosses Piston ring grooves for nicks, burrs, or other warpage which may cause the piston ring to bind
6. Inspect the piston pin for scoring, wear or other damage.
7. Measure the piston ring-to-piston ring groove side clearance. Insert the edge of the piston ring into the piston ring groove. Roll the piston ring completely around the piston ring groove. If binding is caused by distorted piston ring groove, replace the piston. If binding is caused by a distorted piston ring, replace the piston ring.
8. Measure the piston ring side clearance with a feeler gage.
9. If the side clearance is too small try another ring set.
10. If the proper piston ring-to-piston ring groove clearance cannot be achieved, replace the piston and pin assembly. Proper ring-to-piston ring groove clearance for the top ring is 0.03-0.065 mm (0.001-0.002 in). Proper ring-to-piston ring groove clearance for the second ring is 0.04-0.078 mm (0.002-0.003 in).
11. Using the EN-46745 , remove the piston pin retainers (1).
12. Discard the oil piston pin retainers.
13. Slide the piston pin (4) out of the piston (2), disconnecting the piston from the connecting rod (3).
14. Measure the piston pin diameter using and ouside micrometer.
15. Measure the piston pin bore using an inside micrometer.
16. Subtract the piston pin diameter from the piston pin bore diameter in order to determine the piston pin-to-piston pin bore clearance.
17. Piston-to-piston pin bore clearance must measure 0.002-0.010 mm (0.00008-0.0004 in). Replace the piston and the piston pin if the piston and the piston pin are not within specifications.
18. Measure the piston diameter with a micrometer at a right angle to the piston bore with the piston pin removed, and record the measurement. Measure the piston at 43 mm (1.692 in) from dome of piston. Piston diameter must measure no less than 98.950 mm (3.895 in). Replace the piston and the pin as an assembly if the piston is not within specifications.
19. Measure the cylinder bore, using J 8087 .
20. Measure the J 8087 . Record this reading.
21. Subtract the diameter of the piston from the diameter of the cylinder bore to determine the piston-to-bore clearance. The cylinder bore clearance must be no more than 0.080 mm (0.003 in).
22. If a used piston is not acceptable, inspect the service piston size and determine if a new piston may be selected. Service pistons are available in standard and 0.5 mm (0.012 in) oversize.
23. When a piston has been selected, mark the piston in order to identify the cylinder for which the piston was fitted.
24. Inspect the connecting rod for an out-of-round bearing bore. If the out-of-round measurement exceeds 0.005 mm (0.0002 in) the connecting rod must be replaced.
25. Inspect the connecting rod for twisting. Install the connecting rod cap. Place the connecting rod assembly on a checking fixture. Inspect the assembly for bending or twisting. Do not attempt to straighten the connecting rod. Ensure that the connecting rod meets the following conditions: The connecting rods are not bent more than 0.18 mm (0.007 in). The connecting rods are not twisted more than 0.38 mm (0.015 in). Replace any bent or twisted connecting rods. Inspect the new connecting rods before using the new rods.
26. Inspect the connecting rod for damage to the bearing cap and bolt threads.
27. Measure the piston compression ring end gap. IMPORTANT: Fit each compression ring to the cylinder in which it will be used. Place the compression ring into the cylinder bore. Push the compression ring into the bottom of the cylinder bore to approximately 6.5 mm (0.25 in) above ring travel. The ring must be square to the cylinder wall. Use a feeler gage in order to measure the end gap. The first compression ring end gap must measure 0.15-0.30 mm (0.006-0.011 in), the second compression ring must measure 0.25-0.45 mm (0.009-0.017 in). Select another size ring set if the end gap exceeds specifications. If ring gap clearance is below specifications, increase the gap by carefully filing off excess material.
28. Inspect the connecting rod bearings for craters or pockets. Flattened sections on the connecting rod bearing halves may indicate fatigue.
29. Inspect the connecting rod bearings for excess scoring or discoloration.
30. Inspect the connecting rod bearings for dirt or debris imbedded into the connecting rod bearing halves.
31. Inspect the connecting rod bearings for improper seating indicated by bright, polished sections of the bearings.
32. Inspect the inside of the connecting rod bearing and the outside diameter of the connecting rod bearing journal for wear. This indicates high spots.

1. Remove and discard the camshaft position actuator filter (1).
2. Clean the camshaft with cleaning solvent.
3. Inspect the camshaft for the following conditions: Scored camshaft bearing journals (5) Damaged camshaft lobes (4) Damaged camshaft position sensor reluctor area (3) Damaged threads (2)
4. Measure the camshaft journals using a micrometer. If the camshaft journals are not within specifications, replace the camshaft.
5. Measure the camshaft runout using the J 7872 . Mount the camshaft in V-blocks between the centers. Use the J 7872 in order to measure the intermediate camshaft journal.
6. Measure the camshaft lobe lift using the J 7872 . Lubricate the camshaft using GM P/N 12345501 (Canadian P/N 992704) or the equivalent. Set the camshaft on V-blocks. Use the J 7872 in order to measure the lobe lift.
7. If the runout or lobe lift is not within specifications, replace the camshaft.
8. Install a NEW camshaft position actuator filter (1).

Camshaft Timing Chain and Sprocket Cleaning and Inspection

1. Clean all components with cleaning solvent.
2. Dry the components with compressed air.
3. Inspect the timing chain for binding or wear.
4. Inspect the camshaft and crankshaft sprockets for: Worn teeth (1) Broken teeth (2) Chipped teeth (3)
5. Inspect the timing chain tensioner (1) and timing chain tensioner slides (2) for excessive wear or cracks. Repair or replace as required.

Camshaft Position Actuator Magnet Cleaning and Inspection

1. Inspect the camshaft position actuator magnet for the following conditions: The camshaft position actuator magnet wiring connector (1) for damage. The camshaft position actuator magnet O-ring seal and sealing area (2) for damage.
2. Repair or replace the camshaft position actuator housing and/or components as necessary.

Camshaft Position Actuator Cleaning and Inspection

1. Clean the camshaft position actuator components with solvent.
2. Dry the camshaft position actuator components with compressed air.
3. Inspect the camshaft position actuator for the following conditions: The camshaft position actuator mounting bores (1) for damage The camshaft position actuator return spring (2) for nicks or damage The camshaft position actuator valve surface for pitting or damage (3)
4. Replace the camshaft position actuator as necessary.

Valve Lifters Cleaning and Inspection

1. Clean the valve lifters in cleaning solvent.
2. Dry the valve lifters with compressed air.
3. Inspect the valve lifters for the following: Bent or broken clip (1) Worn push rod socket (2) Scuffed or worn sides (3) If the valve lifter shows wear, inspect the engine block lifter bores for wear or damage. Flat spots on the roller (4) Loose or damaged pin (5) Plugged oil hole (6) Worn or damaged roller bearing The roller should rotate freely with no binding or roughness.
4. Inspect the valve lifter guides for the following: For cracks or damage Excessive wear in the lifter mounting bores

Valve Rocker Arm and Push Rod Cleaning and Inspection

1. Clean the valve rocker arms and push rods in cleaning solvent.
2. Dry the valve rocker arms and push rods with compressed air.
3. Inspect the valve rocker arms for the following conditions: Excessive wear at the valve contact or push rod socket area (1) A loose or damaged pin (2) A worn or damaged roller bearing (3)-The roller should rotate freely with no binding or roughness. The bolt threads for damage
4. Inspect the push rods for the following conditions: Straightness using a straight edge (1) Excessive wear on the push rod ends (3) Clogging of the oil passage (2)

Cylinder Head Cleaning and Inspection

Tools Required

1. J 8089 Carbon Removing Brush. See «Special Tools»(ref-301513-S24222073032008101700000) .
2. J 9666 Valve Spring Tester

1. Inspect the cylinder head gasket and the mating surfaces. Inspect for leaks, corrosion, and blowby.
2. If the gasket failed, determine the cause. The following conditions may cause gasket failure: Improper installation A loose or warped cylinder head Missing, off location, or not fully seated dowel pins Low torque on the cylinder head bolts Cylinder head bolts with the incorrect length A warped engine block surface Scratched surfaces Excessive intake manifold torque Cracked engine block threaded holes Porosity
3. Use the J 8089 in order to remove the carbon from the combustion chambers. See «Special Tools»(ref-301513-S24222073032008101700000) .
4. Clean the following components: The gasket surfaces Do not use a motorized brush on any gasket sealing surface. Valve stems and heads on a buffing wheel The bolt hole threads Remove all dirt, debris, or threadlocking material from the bolt holes.
5. Inspect the cylinder head mating surfaces for flatness. Replace the cylinder head if it is outside of the specification limit.
6. Inspect the cylinder head for cracks.
7. Inspect the cylinder head deck for corrosion. Do not attempt to weld the cylinder head. If the cylinder head is damaged, replace the cylinder head.
8. Remove the valve spring dampener.
9. Inspect the valve springs for squareness.
10. Use the J 9666 in order to measure the valve spring tension. Replace the spring if the spring tension is not within specification.
11. Install the valve spring dampener.

Oil Pump Cleaning and Inspection

1. Clean all parts of sludge, oil, and varnish by soaking in cleaning solvent.
2. Inspect for foreign material and determine the source of the foreign material.
3. Inspect the pump housing and cover for the following conditions: Cracks or casting imperfections Scoring (3) Damaged threads
4. Do not attempt to repair the pump housing. Replace the pump housing.
5. Inspect the oil pump gears for the following conditions: Scoring (1) Excessive wear (2)
6. Inspect the idler shaft for looseness or scoring (4). If loose or damaged, replace the oil pump.
7. Inspect the drive gear shaft for looseness or scoring (5).
8. Inspect the pressure regulator valve for the following conditions: Scoring Sticking Burrs may be removed using a fine oil stone.
9. Inspect the pressure regulator valve spring for the following conditions: Loss of tension Bending
10. Inspect the suction pipe and screen assembly for the following conditions: Looseness-If the suction pipe is loose, bent or has been removed, replace the pump body cover and suction pipe. Broken wire mesh or screen
11. Measure the oil pump gear lash. Install the gears, and measure in several places.
12. Measure the oil pump housing gear pocket (1, 2).
13. Measure the oil pump gears (1, 2).
14. Measure the oil pump gear side clearance.

Engine Front Cover Cleaning and Inspection

1. Clean the engine front cover with solvent.
2. Dry the engine front cover with compressed air.
3. Inspect the engine front cover sealing surfaces for damage.
4. Inspect the engine front cover threaded holes.
5. Repair or replace the engine front cover as needed.

Valve Rocker Arm Cover Cleaning and Inspection

1. Remove all rubber grommets from the valve rocker arm covers.
2. Clean the valve rocker arm covers with solvent.
3. Dry the valve rocker arm covers with compressed air.
4. Inspect the valve rocker arm covers for damage and replace if necessary.

Positive Crankcase Ventilation (PCV) Valve Cleaning and Inspection

1. Flush the carbon from the PCV valve orifices (1) using solvent.
2. Dry the PCV valve orifices using compressed air.

Oil Pan Cleaning and Inspection

1. Remove the oil level sensor.
2. Inspect the O-ring seal (2) and the electrical connector (1) for wear or damage. Repair or replace as necessary.
3. Clean the oil pan with solvent. Remove all sludge and debris from the oil pan.
4. Dry the oil pan with compressed air.
5. Inspect the oil pan sealing surface for damage and replace if necessary.
6. Install the oil level sensor and bolt. Tighten: Tighten the oil level sensor bolt to 10 N.m (89 lb in).

Lower Intake Manifold Cleaning and Inspection

1. Clean the intake manifold gasket mating surfaces (3) using GM P/N 12346139 (Canadian P/N 10953463) or equivalent.
2. Clean the fuel injector bores (1).
3. Inspect the lower intake manifold locating pins (2) for damage. Replace as necessary.
4. Inspect the intake manifold for damage.
5. Repair or replace the intake manifold as necessary.

Coolant Crossover Pipe Cleaning and Inspection

1. Clean the coolant crossover pipe with solvent.
2. Dry the coolant crossover pipe with compressed air.
3. Inspect the front of the coolant crossover pipe for the following: Damage to the coolant fill adapter sealing surface (1) Damage or restrictions to the radiator hose connection (2) Damage or restrictions to the thermal bypass hose connection (3) Damage, blockage, or excessive corrosion to the engine coolant passages Damage or restrictions to any fastener threads Damage or restrictions to any mounting holes
4. Inspect the rear of the coolant crossover pipe for the following: Damage to the heater inlet/outlet sealing surface (1) Damage to the coolant crossover pipe-to-cylinder head sealing surfaces (2) Damage, blockage, or excessive corrosion to the engine coolant passages Damage or restrictions to any fastener threads Damage or restrictions to any mounting holes
5. Repair or replace the coolant crossover pipe as necessary.

Upper Intake Manifold Cleaning and Inspection

1. Remove the throttle body bolts and nuts.
2. Remove the throttle body.
3. Remove the throttle body studs, if required.
4. Remove the manifold absolute pressure (MAP) sensor (3).
5. Remove the evaporative emissions (EVAP) purge valve bolt (1).
6. Remove the EVAP purge valve (2).
7. Remove the EVAP purge valve isolator, if equipped.
8. Clean the intake manifold with solvent.
9. Dry the intake manifold with compressed air.
10. Inspect all gasket mating surfaces for nicks or cracks and replace if necessary.
11. Inspect the EVAP purge valve seal for damage and replace if necessary.
12. Install the EVAP purge valve isolator, if equipped.
13. Install the EVAP purge valve.
14. Install the EVAP purge valve bolt (1). Tighten: Tighten the EVAP purge valve bolt to 16 N.m (12 lb ft).
15. Inspect the MAP sensor seal for damage and replace if necessary.
16. Install the MAP sensor (3).
17. Install the throttle body studs, if required. Tighten: Tighten the throttle body studs to 6 N.m (53 lb in).
18. Inspect the throttle body seal for damage and replace if necessary.
19. Install the throttle body.
20. Apply threadlock GM P/N 12345382 (Canadian P/N 10953489) to the throttle body bolt and nut threads.
21. Install the throttle body bolts and nuts. Tighten: Tighten the throttle body bolts and nuts to 10 N.m (89 lb in).

Exhaust Manifold Cleaning and Inspection

1. Clean the exhaust manifold and heat shield in solvent.
2. Dry the exhaust manifold and heat shield with compressed air.
3. Inspect the exhaust manifold for cracks or damage.

Water Pump Cleaning and Inspection

1. Remove all gasket material from the sealing surface.
2. Inspect the water pump impeller for damage.
3. Inspect the water pump shaft for looseness.
4. Replace the water pump if necessary.

Engine Mechanical Diagnostic Procedure Revisions

No revisions for 2007.