Engine Mechanical - 4.3L: Diagnosis Chevrolet Silverado 1500 HD

Diagnostic Starting Point - Engine Mechanical

Begin the system diagnosis by reviewing the Disassembled Views Engine Component Description Lubrication Description , and New Product Information and to Drive Belt System 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 the «DIAGNOSTIC SYSTEM CHECK - ENGINE CONTROLS»(ref-158208-S20709970632003091700000) 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-188990-S08313085232005091300000) «Engine Component Description»(ref-188990-S25429693092005091300000) «Lubrication Description»(ref-188990-S28777281342005091300000) , and «New Product Information»(ref-188990-S07345244632005091300000) and to «Drive Belt System Description»(ref-188990-S27764201712005091300000) . 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.

Visual/Physical Inspection

1. Inspect for aftermarket devices which could affect the operation of the Engine. Refer to «CHECKING AFTERMARKET ACCESSORIES»(ref-189004-S21780885952005091300000) .
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-188990-S31744700112005091300000)
2. «Base Engine Misfire with Abnormal Internal Lower Engine Noises»(ref-188990-S01211075952005091300000)
3. «Base Engine Misfire with Abnormal Valve Train Noise»(ref-188990-S01616013222005091300000)
4. «Base Engine Misfire with Coolant Consumption»(ref-188990-S37228870532005091300000)
5. «Base Engine Misfire with Excessive Oil Consumption»(ref-188990-S06148325112005091300000)
6. «Engine Compression Test»(ref-188990-S21154358792005091300000)
7. «Engine Noise on Start-Up, but Only Lasting a Few Seconds»(ref-188990-S09785870432005091300000)
8. «Upper Engine Noise, Regardless of Engine Speed»(ref-188990-S25530459102005091300000)
9. «Lower Engine Noise, Regardless of Engine Speed»(ref-188990-S00300644732005091300000)
10. «Engine Noise Under Load»(ref-188990-S42364420172005091300000)
11. «Engine Will Not Crank-Crankshaft Will Not Rotate»(ref-188990-S33531740832005091300000)
12. «Oil Consumption Diagnosis»(ref-188990-S37950606532005091300000)
13. «Oil Pressure Diagnosis and Testing»(ref-188990-S19585282432005091300000)
14. «Oil Leak Diagnosis»(ref-188990-S00384291952005091300000)

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Engine Compression Test

1. Ensure that the vehicle batteries are in good condition, and fully charged.
2. Operate the vehicle until the engine is at normal operating temperature.
3. Disconnect the positive ignition coil wire plug from the ignition coil.
4. Disconnect the fuel injector electrical connector.
5. Remove all of the spark plugs. NOTE: Do not insert objects into the throttle plate opening. Damage to the throttle body can result, requiring replacement of the throttle body assembly.
6. Block the throttle linkage wide open.
7. Install the engine cylinder compression gage to the cylinder being tested.
8. Using the vehicle starter motor, rotate, or crank the engine for 4 compression strokes, or puffs, for the cylinder being tested. If the engine rotates for more than 4 compression strokes, test the cylinder again.
9. Record the compression reading.
10. Remove the engine cylinder compression gage from the cylinder being tested.
11. Repeat steps 8-11 for each additional cylinder. All cylinders must be tested to obtain valid test results.
12. If any cylinders have low compression, inject approximately 15 ml (1 oz) of engine oil into the cylinder through the spark plug hole.
13. Repeat steps 8-11 for all low compression cylinders.
14. The minimum compression in any one cylinder should not be less than 70 percent of the highest cylinder. No cylinder should read less than 690 kpa (100 psi). For example, if the highest pressure in any one cylinder is 1035 kPa (150 psi), the lowest allowable pressure for any other cylinder would be 725 kPa (105 psi). Multiply the highest cylinder pressure by 70 percent, 1035 kPa x 70 percent = 725 kPa (150 psi x 70 percent =105 psi), in order to determine the lowest allowable pressure in any other cylinder. Normal The compression builds up quickly and evenly to the specified compression. Piston rings leaking Compression is low on the first compression stroke. The compression builds up on the following strokes, but does not reach normal. Compression improves considerably when you add oil. Valves leaking Compression is low on the first compression stroke. The compression does not build up on the following strokes, and does not reach normal. Compression does not improve much, if at all, when you add oil. Head gasket leaking Compression is low on the first stroke. The compression does not build up on the following strokes, and does not reach normal. Compression Compression does not improve much, if at all, when you add oil. Adjacent cylinders have the same, or similar, low compression readings.
15. If one or more cylinders fails to meet the minimum specified compression, repair or replace all damaged or worn components and test the engine again.

Oil Consumption Diagnosis

Excessive oil consumption, not due to leaks, is the use of 1 liter (1 quart) of engine oil within 3 200 kilometers (2,000 miles). However, during initial engine break-in periods 4 828-6 437 kilometers (3,000-4,000 miles), oil consumption may exceed 1 liter (1 quart) or more. The causes of excessive oil consumption include the following conditions

1. External oil leaks Tighten the bolts and/or replace gaskets and oil seals as necessary.
2. Incorrect oil level or improper reading of oil level indicator With the vehicle on a level surface, allow adequate drain down time and check for the correct oil level.
3. Improper oil viscosity Use recommended SAE viscosity for the prevailing temperatures.
4. Continuous high speed driving and/or severe usage
5. Crankcase ventilation system restrictions or malfunctioning components
6. Valve guides and/or valve stem oil seals worn, damaged, or the seal omitted Ream the valve guides and install oversize service valves and/or new valve stem oil seals.
7. Piston rings broken, improperly installed, worn, or not seated properly Allow adequate time for the piston rings to seat. Replace broken or worn piston rings as necessary.
8. Piston improperly installed or miss-fitted

Oil Pressure Diagnosis and Testing

1. With the vehicle on a level surface, allow adequate drain down time, 2-3 minutes, and measure for a low engine oil level. Add the recommended grade engine oil, and fill the crankcase until the oil level measures FULL on the oil level indicator.
2. Operate the engine and verify low or no oil pressure on the vehicle oil pressure gage or the oil indicator light. Listen for a noisy valve train or a knocking noise.
3. Inspect for the following: Engine oil diluted by moisture or unburned fuel mixtures Improper engine oil viscosity for the expected temperature Incorrect or faulty oil pressure gage sensor Incorrect or faulty oil pressure gage Plugged oil filter Malfunctioning oil filter bypass valve
4. Remove the oil pressure gage sensor or another engine block oil gallery plug.
5. Install an oil pressure gage.
6. Start the engine and then allow the engine to reach normal operation temperature.
7. Measure the engine oil pressure at the following RPM: Specification 7.1. 42 kPa (6 psig) minimum, at 1,000 RPM 7.2. 125 kPa (18 psig) minimum, at 2,000 RPM 7.3. 166 kPa (24 psig) minimum, at 4,000 RPM
8. If the engine oil pressure is below minimum specifications, inspect the engine for one or more of the following: Oil pump worn or dirty Malfunctioning oil pump pressure relief valve Oil pump screen loose, plugged, or damaged Excessive bearing clearance Cracked, porous or restricted oil galleries Engine block oil gallery plugs missing or incorrectly installed Broken valve lifters

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Diagnostic Aids

The chirping noise may be intermittent due to moisture on the drive belt or the accessory drive pulley(s). In order to duplicate the customer's concern, It may be necessary to spray a small amount of water onto the drive belt. If spraying water onto the drive belt duplicates the symptom, cleaning the accessory belt pulley(s) may be the most probable solution.

A loose or improper installation of a body or suspension component, or other item(s) on the vehicle may also cause the chirping noise.

A loose or improper installation of a body or suspension component, or other item(s) on the vehicle may cause the squeal noise.

If the squeal is intermittent, verify that it is not the accessory drive component(s) by varying their load(s), making sure they are operating to their maximum capacity. An overcharged air conditioning (A/C) system, a power steering system restriction or the incorrect fluid, or a failing generator are suggested items to inspect.

The drive belt will not cause the whine. If the whine is intermittent, verify that it is not the accessory drive component(s) by varying their load(s), making sure they are operating to their maximum capacity. An overcharged air conditioning (A/C) system, a power steering system restriction or the incorrect fluid, or a failing generator are suggested items to inspect.

Vibration from the engine operating may cause a body component or another part of the vehicle to make a rumbling noise.

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

If after replacing the drive belt and completing the diagnostic table, the rumbling is only heard with the drive belt is installed, there might be an accessory drive component failure. Varying the load on the accessory drive component(s) may aid in identifying which component is causing the rumbling noise.

The accessory drive components may have an affect on engine vibration. An overcharged air conditioning (A/C) system, a power steering system restriction, or the incorrect fluid, or an extra load placed on the generator are suggested items to inspect. To help identify an intermittent or an improper condition, vary the loads on the accessory drive components.

If the drive belt repeatedly falls off the accessory drive belt pulley(s), this may be caused by a pulley misalignment.

An extra load that is quickly applied or released by an accessory drive component may also cause the drive belt to fall off. Verify that the accessory drive component(s) are operating properly.

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

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

Minor misalignment of the accessory drive belt pulley(s) will not cause excessive wear, but will probably cause the drive belt to make a noise or fall off.

Excessive misalignment of the accessory drive pulley(s) will cause excessive wear and may also make the drive belt fall off.

Engine Mount Inspection

Note. Refer to ENGINE MOUNTING NOTICE .

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1. Raise and suitably support the vehicle. Refer to «JACKING AND LIFTING»(ref-188958) .
2. Inspect for loose or missing bolts at the following locations: Engine mount bracket to engine Engine mount frame bracket to frame Engine mount to engine mount bracket Engine mount to engine mount frame bracket
3. Replace missing or loose bolts. NOTE: Refer to «ENGINE LIFTING NOTICE»(ref-175132-S39980754042005041500000) .
4. In order to access the square tab on the right side of the engine remove the starter. Refer to «STARTER MOTOR»(ref-168656-S31439200122004111300000) .
5. Using a jack on the square tab at the rear of the engine block (left side shown) raise the engine in order to complete the following tasks: Remove weight from the engine mount. Place a slight tension on the rubber cushion. Observe the engine mount while raising the engine.
6. Replace the engine mount if the following conditions exist: Heat check cracks cover the hard rubber surface. The rubber cushion is separated from the metal plate of the engine mount. There is a split through the rubber cushion.
7. Install the starter, if removed. Refer to «STARTER MOTOR»(ref-168656-S31439200122004111300000) .

Piston, Connecting Rod, and Bearings Cleaning and Inspection

Do not use a wire brush in order to clean any part of the piston.

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1. Clean the piston and connecting rod in solvent. CAUTION: Refer to «SAFETY GLASSES CAUTION»(ref-175132-S23208358672005041500000) .
2. Dry the components 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. 7.1. Insert the edge of the piston ring into the piston ring groove. 7.2. Roll the piston ring completely around the piston. If binding is caused by a distorted piston ring groove, MINOR imperfections may be removed with a fine file. If binding is caused by a distorted piston ring, replace the piston ring.
8. Measure the piston ring side clearance with a feeler gauge.
9. If the side clearance is too small, try another piston ring set.
10. If the proper piston ring-to-piston ring groove clearance cannot be achieved, replace the piston and pin assembly.
11. To determine the proper piston ring side clearance, refer to «Engine Mechanical Specifications»(ref-188990-S11849719982005091300000) .
12. Inspect the connecting rod for an out-of-round bearing bore. Refer to «Engine Mechanical Specifications»(ref-188990-S11849719982005091300000) .
13. Inspect the connecting rod for twisting.
14. Inspect the connecting rod for damage to the bearing cap and bolt threads.
15. Measure the piston compression ring end gap. IMPORTANT: Fit each compression ring to the cylinder in which it will be used. 15.1. Place the compression ring into the cylinder bore. 15.2. Push the compression ring into the cylinder bore to approximately 6.5 mm (0.25 in) above the ring travel. The ring must be square to the cylinder wall. 15.3. Use a feeler gage in order to measure the end gap. 15.4. Select another size ring set if the end gap exceeds specifications. Refer to «Engine Mechanical Specifications»(ref-188990-S11849719982005091300000) .

Crankshaft Balancer Cleaning and Inspection

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1. Clean the crankshaft balancer in cleaning solvent.
2. Dry the crankshaft balancer with compressed air.
3. Inspect the crankshaft balancer for the following: Loose or improperly installed crankshaft balancer front groove pin (1) A properly installed front groove pin should be installed until flush or below flush with the face of the crankshaft balancer. IMPORTANT: A crankshaft front oil sealing surface with excessive scoring, grooves, rust, or other damage must be replaced. Worn, grooved, or damaged crankshaft front oil sealing surface (2) Minor imperfections on the crankshaft balancer crankshaft front oil seal surface may be removed with a polishing compound or fine grade emery cloth. Worn, chunking, or deteriorated rubber (3) between the hub and the outer ring Worn or damaged keyway (4) Worn or damaged bolt hole threads (5)

Engine Flywheel Cleaning and Inspection

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1. Clean the engine flywheel (1 or 2) in cleaning solvent.
2. Dry the engine flywheel with compressed air. IMPORTANT: Do not attempt to repair the welded areas, if present, that retain the ring gear to the engine flywheel plate. Always install a NEW engine flywheel.
3. Inspect the engine flywheel, automatic transmission, if equipped, for the following: Stress cracks around the engine flywheel-to-torque converter bolt hole locations (1) Missing balance weights Stress cracks around the engine flywheel-to-crankshaft bolt hole locations (2 or 3) Welded areas that retain the ring gear onto the engine flywheel for cracking (4), if present Damaged ring gear teeth (5)
4. Inspect the engine flywheel, manual transmission, if equipped, for loose or improperly installed flywheel weights, if applicable. A properly installed flywheel weight should be installed until flush or below flush with the face of the engine flywheel.
5. Inspect the engine flywheel, manual transmission, if equipped, for the following: Pitted friction surface (1) Scoring or grooves (2) Rust or other surface damage (3) Damaged ring gear teeth (4) Loose or improperly positioned ring gear The ring gear has an interference fit onto the engine flywheel and the ring gear should be positioned completely flat against the flange of the engine flywheel.

Balance Shaft Cleaning and Inspection

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1. Clean the following components in cleaning solvent: The balance shaft (1) The balance shaft retainer (2) The balance shaft rear bearing The balance shaft driven gear (4) The balance shaft drive gear
2. Dry the following components with compressed air: The balance shaft (1) The balance shaft retainer (2) The balance shaft rear bearing The balance shaft driven gear (4) The balance shaft drive gear
3. Inspect the balance shaft bearings for the following: Front ball bearing for damage or wear Front ball bearing for smoothness of operation Rear sleeve bearing for wear, scoring, or other damage
4. Inspect the balance shaft (1) for the following: Wear or scoring on the rear bearing journal Damaged bolt hole threads Damage to the balance shaft driven gear locator pin
5. Inspect the balance shaft retainer (2) for wear or damage.
6. Inspect the balance shaft retainer bolts (3) for damaged threads.
7. Inspect the driven gear (4) for the following: Excessive wear or damage Nicks, burrs, or scoring
8. Inspect the driven gear bolt (5) for damaged threads.
9. Inspect the balance shaft drive gear for the following: Excessive wear or damage Nicks, burrs, or scoring

Timing Chain and Sprockets Cleaning and Inspection

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1. Clean the components with cleaning solvent.
2. Dry the components with compressed air.
3. Inspect the camshaft timing chain for binding or wear.
4. Inspect the camshaft sprocket and the crankshaft sprocket for: Broken teeth (1) Damaged teeth (2) Chipped teeth (3) Worn teeth Uneven wear on the edge of the teeth Worn valleys between the sprocket teeth Crankshaft sprocket keyway for wear

Valve Rocker Arm and Push Rods Cleaning and Inspection

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1. Mark, sort, and organize the components for assembly. CAUTION: Refer to «SAFETY GLASSES CAUTION»(ref-175132-S23208358672005041500000) .
2. Clean the components with cleaning solvent.
3. Dry the components with compressed air.
4. Inspect the valve rocker arm components for the following: Valve rocker arm valve pushrod socket contact surface (1) The contact surface must be smooth with no scoring or excessive wear. Valve rocker arm roller pivot for binding or damage (2) Valve rocker arm valve stem contact surface (3) The contact surface should be smooth with no scoring or excessive wear. Valve rocker arm bolt threads for damage (4)
5. Inspect the valve pushrods for the following: Restriction of the oil passage (1) Wear or scoring of the end contact surfaces (2) The end contact surfaces must be smooth with no scoring or excessive wear. Shaft for bends (3) Roll the valve pushrod on a flat surface to determine if the valve pushrod is bent.
6. Inspect the valve rocker support for excessive wear or damage.

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1. Mark, sort, and organize the components for assembly. CAUTION: Refer to «SAFETY GLASSES CAUTION»(ref-175132-S23208358672005041500000) .
2. Clean the components in cleaning solvent.
3. Dry the components with compressed air.
4. Inspect the valve lifter pushrod guides for excessive wear.
5. Inspect the valve lifter pushrod guides for cracks or damage.
6. Inspect the valve lifter for the following: Broken or damaged clip (1) Worn pushrod socket (2) Scuffed or worn lifter body (3) If the valve lifter shows scuffing or wear, inspect the engine block valve lifter bores for wear. Worn roller (4) Loose or damaged pin (5) Plugged oil hole (6)

Oil Pump Cleaning and Inspection

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1. Clean the oil pump components in cleaning solvent.
2. Dry the components with compressed air.
3. Inspect the oil pump for the following conditions: Scoring on the top of the gears (1) Damaged gears (2) for the following: Chipping Galling Wear Scoring, damage or casting imperfections to the body (3) Damaged or scored gear shaft (4) Damaged or scored gear shaft (5) Damaged bolt hole threads Worn oil pump driveshaft bore Damaged or sticking oil pump pressure relief valve Minor imperfections may be removed with a fine oil stone. Collapsed or broken oil pump pressure relief valve spring
4. If the oil pump is to be reused, install a NEW oil pump pressure relief valve spring.
5. During oil pump installation, install a NEW oil pump driveshaft retainer.

Valve Rocker Arm Cover Cleaning and Inspection

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1. Clean the valve rocker arm cover in cleaning solvent.
2. Dry the valve rocker arm cover with compressed air.
3. Inspect the valve rocker arm cover for the following: Damage to the PCV valve grommet (1) Damage to the bolt holes (2) A damaged valve rocker arm cover may interfere with the valve rocker arms. Damage to the exterior of the valve rocker arm cover (3) Gouges or damage to the sealing surface (4) Damage to the oil fill tube grommet (5) Restrictions to the ventilation system passages

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1. Remove the oil pan baffle bolts and the oil pan baffle. CAUTION: Refer to «SAFETY GLASSES CAUTION»(ref-175132-S23208358672005041500000) .
2. Clean the oil pan and oil pan baffle in cleaning solvent.
3. Dry the oil pan and oil pan baffle with compressed air.
4. Inspect the oil pan for the following: Gouges or damage to the oil pan sealing surfaces (1) Damage to the threaded holes (2) Damaged oil pan drain hole threads (3) Damage to the oil pan baffle Damage to the exterior of the oil pan A damaged oil pan may interfere with the proper position of the oil pump screen, or may not distribute oil properly in the oil pan sump area. NOTE: Refer to «FASTENER NOTICE»(ref-175132-S17785009232005041500000) .
5. Install the oil pan baffle and the bolts. Tighten Tighten the oil pan baffle bolts to 12 N.m (106 lb in).

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1. Remove the nuts, the studs, and the accelerator control cable bracket.
2. Remove the throttle body attaching studs.
3. Remove the throttle body.
4. Remove the throttle body to upper intake manifold gasket.
5. Discard the throttle body to upper intake manifold gasket.
6. Remove the water outlet studs.
7. Remove the water outlet (1 or 2).
8. Remove the engine coolant thermostat.
9. Remove the engine coolant temperature (ECT) sensor plug (1) or the ECT sensor (2) from the front of the lower intake manifold, if equipped.
10. Remove the studs and the ignition coil.
11. Remove the manifold absolute pressure (MAP) sensor.
12. Remove the MAP sensor seal from the MAP sensor.
13. Discard the MAP sensor seal.
14. Remove the fuel pipe bolt (4).
15. Remove the fuel pipe retainer nuts (1).
16. Remove the fuel pipe retainer (2).
17. Remove the fuel pipe (3).
18. Remove and discard the fuel seal retainers (5).
19. Remove and discard the fuel seals (6), yellow O-rings.
20. Remove and discard the spacer rings (7), flat washers.
21. Remove and discard the fuel seals (8), black O-rings.
22. Remove the studs and the evaporative emission (EVAP) canister purge solenoid valve.
23. Remove the nut and the engine wiring harness bracket.
24. Remove the upper intake manifold attaching studs.
25. Remove the upper intake manifold.
26. Remove the upper intake manifold to lower intake manifold gasket.
27. Discard the upper intake manifold to lower intake manifold gasket.
28. Remove the fuel meter body seal and discard.
29. Remove the 6 injectors from the lower intake manifold bores.
30. Remove the fuel meter body.
31. Remove the bolt and the fuel meter body bracket.

Intake Manifold Cleaning and Inspection

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1. Clean the upper intake manifold in cleaning solvent.
2. Dry the upper intake manifold with compressed air.
3. Clean the lower intake manifold in cleaning solvent.
4. Dry the lower intake manifold with compressed air.
5. Inspect the upper intake manifold for the following: Cracks or other damage to the exterior (1) Cracking or damage in the gasket grooves (2) and (3) Damage to the throttle body mounting surface (4) Loose or damaged bolt hole thread inserts (5)
6. Inspect the lower intake manifold for the following: Damage to the gasket sealing surfaces (1) and (2) Restricted cooling system passages (3) Cracks or damage Damage to the threaded bolt holes

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1. If reusing the fastener, apply threadlock GM P/N 12345382 (Canadian P/N 10953489) or equivalent, to the threads of the fuel meter body bracket bolt. NOTE: Refer to «FASTENER NOTICE»(ref-175132-S17785009232005041500000) .
2. Install the fuel meter body bracket and bolt. Tighten Tighten the fuel meter bracket bolt to 10 N.m (89 lb in). IMPORTANT: All injector lines must face forward as the fuel meter body is snapped into the bracket. Also, the number three fuel tube must be positioned behind the number one fuel tube to eliminate interference with the upper intake manifold when installed.
3. Install the fuel meter body into the fuel meter body bracket.
4. Install the 6 injectors into the proper lower intake manifold bores in proper sequence (3, 5, 1, 2, 4, 6).
5. Inspect the injectors in order to ensure that they are firmly seated and locked in the lower intake manifold bores.
6. Ensure that the electrical connections of the injectors are positioned so that they do not interfere with each other, and are pointing towards the center of the intake manifold. Rotate the electrical connector inboard if necessary. Also, ensure there is no tension on the injector wires.
7. Install a NEW upper intake manifold to lower intake manifold gasket into the groove of the upper intake manifold.
8. Install the upper intake manifold onto the lower intake manifold.
9. If reusing the fasteners, apply threadlock GM P/N 12345382 (Canadian P/N 10953489) or equivalent, to the threads of the upper intake manifold attaching studs.
10. Install the upper intake manifold attaching studs. Tighten 10.1. Tighten the upper intake manifold attaching studs on the first pass to 5 N.m (44 lb in). 10.2. Tighten the upper intake manifold attaching studs on the final pass to 9 N.m (80 lb in).
11. If reusing the fasteners, apply threadlock GM P/N 12345382 (Canadian P/N 10953489) or equivalent, to the threads of the evaporative emission (EVAP) canister purge solenoid valve studs.
12. Install the EVAP canister purge solenoid valve and studs. Tighten Tighten the EVAP canister purge solenoid valve studs to 10 N.m (89 lb in).
13. Install the engine wiring harness bracket and nut. Tighten Tighten the engine wiring harness bracket nut to 12 N.m (106 lb in).
14. Install the NEW fuel seals (8), black O-rings, into the fuel meter body.
15. Install the NEW spacer rings (7), flat washers, into the fuel meter body.
16. Install the NEW fuel seals (6), yellow O-rings, into the fuel meter body.
17. Install the NEW fuel seal retainers (5) into the fuel meter body.
18. Install the fuel pipe (3) into the fuel meter body.
19. Install the fuel pipe retainer bracket (2) onto the fuel pipe.
20. Install the fuel pipe retainer bracket nuts (1).
21. If reusing the fastener, apply threadlock GM P/N 12345382 (Canadian P/N 10953489) or equivalent, to the threads of the fuel pipe bolt.
22. Install the fuel pipe bolt (4). Tighten 22.1. Tighten the fuel pipe bracket nuts to 3 N.m (27 lb in). 22.2. Tighten the fuel pipe bolt to 6 N.m (53 lb in).
23. Install a NEW manifold absolute pressure (MAP) sensor seal onto the MAP sensor.
24. Apply a small amount, approximately 1 drop, of clean engine oil to the MAP sensor seal.
25. Install the MAP sensor into the upper intake manifold.
26. Install the ignition coil and studs. Tighten Tighten the ignition coil studs to 12 N.m (106 lb in).
27. If reusing the engine coolant temperature (ECT) sensor plug (1) or the ECT sensor (2), if equipped, apply sealant GM P/N 12346004 (Canadian P/N 10953480) or equivalent, to the threads of the ECT sensor plug (1) or the ECT sensor (2).
28. Install the ECT sensor or plug, if equipped, into the front of the lower intake manifold. Tighten Tighten the ECT sensor or plug to 20 N.m (15 lb ft).
29. Install the engine coolant thermostat.
30. Install the water outlet (1 or 2).
31. Install the water outlet studs. Tighten Tighten the water outlet studs to 25 N.m (18 lb ft).
32. Install a NEW throttle body gasket into the groove in the upper intake manifold.
33. Install the throttle body onto the upper intake manifold.
34. If reusing the fasteners, apply threadlock GM P/N 12345382 (Canadian P/N 10953489) or equivalent, to the threads of the throttle body attaching studs.
35. Install the throttle body attaching studs. Tighten Tighten the throttle body attaching studs to 9 N.m (80 lb in).
36. Install the accelerator control cable bracket, the studs, and the nuts. Tighten 36.1. Tighten the accelerator control cable bracket stud to the intake manifold to 6 N.m (53 lb in). 36.2. Tighten the accelerator control cable bracket nuts to 12 N.m (106 lb in). 36.3. Tighten the accelerator control cable bracket stud to the throttle body to 12 N.m (106 lb in).

Exhaust Manifold Cleaning and Inspection

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1. Clean the exhaust manifolds in cleaning solvent.
2. Dry the components with compressed air.
3. Inspect the exhaust manifolds for the following: Damage to the gasket sealing surfaces (1) Damage to the threaded holes (2) Restrictions within exhaust passages Broken or damaged exhaust manifold heat shields (3), if applicable Broken or damaged exhaust manifold
4. Measure the alignment or surface flatness of the exhaust manifold flanges using a straight edge and a feeler gage. Refer to «Engine Mechanical Specifications»(ref-188990-S11849719982005091300000) . If the surface flatness is not within the specifications, the exhaust manifold is warped and must be replaced.

Water Pump Cleaning and Inspection

Scheme 158

1. Remove the old gasket material from the water pump sealing surfaces.
2. Clean all the dirt and any debris from the water pump.
3. Inspect the water pump for the following: Leakage or damage to the housing cover or gasket (1) Excessive scratches or gouging to the gasket sealing surfaces (2) Leakage from the water pump vent hole (3) A stain around the vent hole is acceptable. If leakage occurred (dripping) with the engine operating and the cooling system pressurized, then replace the water pump. Damaged bolt hole threads (4) Excessive side-to-side movement of the water pump shaft (5) Leakage around the water inlet pipe (6) Leakage around the heater hose pipe (7) Restrictions within the internal coolant passages

Engine Mechanical Diagnostic Procedure Revisions

1. Coolant in Combustion Chamber diagnostic information has been added.
2. Coolant in Engine Oil diagnostic information has been added.