Engine Mechanical - 2.4L: Diagnosis GMC Terrain I

Strategy Based Diagnostics

1. Perform the «Diagnostic System Check - Vehicle»(ref-491140-S24065023222012073000000) 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-491134-S22420584352012073000000) ,, «Engine Component Description (LAF, LEA, or LUK)»(ref-491134-S25425121982012073000000) ,, and «Lubrication Description»(ref-491134-S20862225662012073000000) .

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 condition. 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.
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-491134-S22947592582012073000000)
2. «Base Engine Misfire with Abnormal Internal Lower Engine Noises»(ref-491134-S09985178342012073000000)
3. «Base Engine Misfire with Abnormal Valve Train Noise»(ref-491134-S00043476442012073000000)
4. «Base Engine Misfire with Coolant Consumption»(ref-491134-S10324250772012073000000)
5. «Base Engine Misfire with Excessive Oil Consumption»(ref-491134-S40004445092012073000000)
6. «Engine Noise on Start-Up, but Only Lasting a Few Seconds»(ref-491134-S32792215372012073000000)
7. «Upper Engine Noise, Regardless of Engine Speed»(ref-491134-S02589833782012073000000)
8. «Lower Engine Noise, Regardless of Engine Speed»(ref-491134-S12955920232012073000000)
9. «Engine Noise Under Load»(ref-491134-S40701447462012073000000)
10. «Engine Will Not Crank - Crankshaft Will Not Rotate»(ref-491134-S05947467382012073000000)
11. «Engine Compression Test»(ref-491134-S37357677102012073000000)
12. «Oil Consumption Diagnosis»(ref-491134-S04866654052012073000000)
13. «Oil Pressure Diagnosis and Testing»(ref-491134-S29408736172012073000000)
14. «Oil Leak Diagnosis»(ref-491134-S05539743332012073000000)
15. «Drive Belt Chirping, Squeal, and Whine Diagnosis»(ref-491134-S25116541062012073000000)
16. «Drive Belt Rumbling and Vibration Diagnosis»(ref-491134-S21463378042012073000000)
17. «Drive Belt Falls Off and Excessive Wear Diagnosis»(ref-491134-S12699175702012073000000)
18. «Drive Belt Tensioner Diagnosis»(ref-491134-S01358451972012073000000)

Engine Compression Test

1. Charge the battery if the battery is not fully charged.
2. Disable the ignition system.
3. Disable the fuel injection system.
4. Remove all spark plugs.
5. Turn the ignition to the ON position.
6. Depress the accelerator pedal to position the throttle plate wide open.
7. Start with the compression gauge at zero and crank the engine through 4 compression strokes, 4 puffs.
8. Measure the compression for each cylinder. Record the readings.
9. If a cylinder has low compression, inject approximately 15 ml (1 tablespoon) of engine oil into the combustion chamber through the spark plug hole. Measure the compression again and record the reading.
10. The minimum compression in any 1 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 1 cylinder is 1 035 kPa (150 psi), the lowest allowable pressure for any other cylinder would be 725 kPa (105 psi). (1 035 x 70% = 725) (150 x 70% = 105). Normal - Compression builds up quickly and evenly to the specified compression for each cylinder. Piston Rings Leaking - Compression is low on the first stroke. Compression builds up with the following strokes, but does not reach normal. Compression improves considerably when you add oil. Valves Leaking - Compression is low on the first stroke. Compression usually does not build up on the following strokes. Compression does not improve much when you add oil. If 2 adjacent cylinders have lower than normal compression, and injecting oil into the cylinders does not increase the compression, the cause may be a head gasket leaking between the cylinders.

Cylinder Leakage Test

Special Tools

EN 35667-A Cylinder Head Leakdown Tester

For equivalent regional tools, refer to Special Tools .

Note. A leakage test may be performed in order to measure cylinder/combustion chamber leakage. High leakage may indicate one or more of the following

1. Worn or burnt valves
2. Broken valve springs
3. Stuck valve lash adjusters
4. Incorrect valve lash/adjustment
5. Damaged piston
6. Worn piston rings
7. Worn or scored cylinder bore
8. Damaged cylinder head gasket
9. Cracked or damaged cylinder head
10. Cracked or damaged engine block

1. Disconnect the battery ground negative cable.
2. Remove the spark plugs. Refer to «Spark Plug Replacement»(ref-491198-S18035247222012073000000) .
3. Rotate the crankshaft to place the piston in the cylinder being tested at Top Dead Center (TDC) of the compression stroke.
4. Install the EN 35667-A tester or equivalent.
5. Apply shop air pressure to the EN 35667-A tester and adjust according to the manufacturers instructions.
6. Record the cylinder leakage value. Cylinder leakage that exceeds 25 percent is considered excessive and may require component service. In excessive leakage situations, inspect for the following conditions: Air leakage sounds at the throttle body or air inlet hose that may indicate a worn or burnt intake valve or a broken valve spring. Air leakage sounds at the exhaust system tailpipe that may indicate a worn or burnt exhaust valve or a broken valve spring. Air leakage sounds from the crankcase, oil level indicator tube, or oil fill tube that may indicate worn piston rings, a damaged piston, a worn or scored cylinder bore, a damaged engine block or a damaged cylinder head. Air bubbles in the cooling system may indicate a damaged cylinder head or a damaged cylinder head gasket.
7. Perform the leakage test on the remaining cylinders and record the values.

Oil Consumption Diagnosis

Excessive oil consumption, not due to leaks, is the use of 0.9 L (1 qt) or greater of engine oil within 3 200 kilometers (2, 000 miles). The causes of excessive oil consumption include the following conditions

1. External oil leaks Tighten 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 inspect 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, or the seal omitted Ream 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 rings to seat. Replace broken or worn rings, as necessary.
8. Piston improperly installed or mis-fitted

Oil Pressure Diagnosis and Testing

Special Tools

1. CH-48027 Digital Pressure Gauge
2. EN-21867-850 Oil Pressure Gauge Adapter

For equivalent regional tools, refer to Special Tools .

1. With the vehicle on a level surface, allow adequate drain down time of 2-3 minutes and measure for a low oil level. Add the recommended grade engine oil and fill the crankcase until the oil level measures full on the oil level indicator.
2. Run the engine, and verify low, or no oil pressure on the vehicle gauge or light. Listen for a noisy valve train or a knocking noise.
3. Inspect for the following: Correct oil filter with anti-drain back feature and O-ring on the cylinder block side of the filter Oil diluted by moisture or unburned fuel mixtures Improper oil viscosity for the expected temperature Incorrect or malfunctioning oil pressure sender Incorrect or malfunctioning oil pressure gauge Plugged oil filter Malfunctioning oil bypass valve
4. Remove the oil pressure sender or another engine block oil gallery plug.
5. Install EN-21867-850 adapter and CH-48027 gauge and measure the engine oil pressure.
6. Compare the readings to specifications. Refer to «Engine Mechanical Specifications (LAF, LEA, or LUK)»(ref-491134-S07132447052012073000000) .
7. If the engine oil pressure is below specifications, inspect the engine for one or more of the following: Correct oil filter with anti-drain back feature and O-ring on the cylinder block side of the filter Oil pump worn or dirty Refer to «Oil Pump Disassemble»(ref-491134-S10231171992012073000000) . Oil pump-to-engine front cover bolts loose Refer to «Engine Front Cover and Oil Pump Installation»(ref-491134-S03139798922012073000000) . Oil pump screen loose, plugged, or damaged Oil pump screen O-ring seal missing or damaged Malfunctioning oil pump pressure regulator valve Excessive bearing clearance Refer to «Crankshaft and Bearing Cleaning and Inspection»(ref-491134-S38807076202012073000000) . Cracked, porous or restricted oil galleries Oil gallery plugs missing or incorrectly installed Refer to «Engine Block Assemble»(ref-491134-S23600199002012073000000) . Broken lash adjusters

Oil Leak Diagnosis

Oil Leak Diagnosis

Crankcase Ventilation System Inspection/Diagnosis (Without Turbocharger)

Special Tools

EN 23951 Valve Manometer

1. Remove the oil level indicator. Install a EN 23951 valve manometer or equivalent.
2. Start the engine.
3. Check for slight vacuum. The vacuum level should be less than 3.377 kPa (1 in Hg).
4. If vacuum is higher, inspect and verify that the clean air hose from cam cover to air intake is not blocked or kinked.
5. If vacuum is in the normal range, block or pinch off the clean air hose. The clean air hose is the hose between the cam cover and air intake system. Vacuum should increase on the manometer. If held too long, vacuum will be drawn through the crankshaft seals creating a sucking sound.
6. If vacuum does not increase, the orifice in the intake manifold could be plugged.
7. If there is zero vacuum or pressure, verify compression of the engine.
8. If compression is normal, check for a blocked orifice at the intake manifold. Clean the orifice.

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

Drive Belt Tensioner Diagnosis

Scheme 3

Intake Manifold Cover Replacement

Scheme 4

Drive Belt Replacement

Scheme 5

Drive Belt Tensioner Replacement

Scheme 6

Engine Oil Pressure Switch Replacement

Engine Mount Inspection

1. Install the engine support fixture. Refer to «Engine Support Fixture»(ref-491177-S27957248262012073000000) .
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 - Right Side»(ref-491177-S07440993392012073000000) .

Scheme 7

Engine Mount Bracket Replacement

Scheme 8

Engine Mount Replacement - Right Side

Engine Block Cleaning and Inspection

Special Tools

1. EN-8087 Cylinder Bore Gauge
2. GE-7872 Magnetic Base Dial Indicator

For equivalent regional tools, refer to Special Tools .

1. Clean the sealing material from the gasket mating surfaces (2) with a suitable tool (1).
2. Clean the engine block and lower crankcase in a cleaning tank with solvent appropriate for aluminum.
3. Flush the engine block with clean water or steam.
4. Clean the oil passages.
5. Clean the blind holes.
6. Inspect the cylinder bores for glazing. If the bore is glazed but otherwise serviceable, refer to Deglazing Procedure in «Cylinder Boring and Honing (LAF, LEA, or LUK)»(ref-491134-S15610251892012073000000) .
7. Spray the cylinder bores and the machined surfaces with engine oil.
8. Inspect the threaded holes. Clean the threaded holes with a rifle brush. If necessary, drill out the holes and install thread inserts. Refer to «Thread Repair»(ref-491134-S13704091462012073000000) .
9. Use a straight edge (1) and a feeler gauge (2) to check the deck surface for flatness. Carefully machine minor irregularities. Replace the block if more than 0.254 mm (0.010 in) must be removed.
10. Inspect the oil pan rail for nicks. Inspect the front cover attaching area for nicks. Use a flat mill file to remove any nicks.
11. Clean the sealing material from the gasket mating surfaces on the lower crankcase engine block side with a suitable tool (1).
12. Clean the sealing material from the gasket mating surfaces on the lower crankcase oil pan side with a suitable tool (1).
13. Inspect the mating surfaces of the transmission face.
14. Use the following procedure in order to measure the engine block flange runout at the mounting bolt hole bosses: Temporarily install the crankshaft and upper bearings. Measure the crankshaft flange runout using the GE-7872 dial indicator (1) Hold the gauge plate flat against the crankshaft flange. 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 0.203 mm (0.008 in). Recheck the crankshaft flange runout if the readings vary more than 0.203 mm (0.008 in). Remove the crankshaft and bearings.
15. Install the bed plate and bolts. Tighten the bed plate bolts to specification.
16. Inspect the crankshaft main bearing bores. Use the EN-8087 gauge (1) to measure the bearing bore concentricity and alignment. Refer to «Engine Mechanical Specifications (LAF, LEA, or LUK)»(ref-491134-S07132447052012073000000) .
17. Replace the engine block and bed plate if the crankshaft bearing bores are out of specification.
18. Remove the bed plate.

Crankshaft Balancer Cleaning and Inspection

1. Clean the crankshaft balancer (1).
2. Clean the belt grooves of all dirt or debris with a wire brush.
3. Dry the crankshaft balancer with compressed air.
4. Inspect the crankshaft balancer for the following: Worn, grooved, or damaged hub seal surface A crankshaft balancer hub seal surface with excessive scoring, grooves, rust or other damage must be replaced. NOTE: In order for the belt to track properly, the belt grooves should be free of all dirt or debris. Dirty or damaged belt grooves The balancer belt grooves should be free of any nicks, gouges, or other damage that may not allow the belt to track properly. Minor imperfections may be removed with a fine file. Worn, chunking or deteriorated rubber between the hub and pulley

Engine Flywheel Cleaning and Inspection

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

Crankshaft and Bearing Cleaning and Inspection

Special Tools

GE-7872 Magnetic Base Dial Indicator Set

For equivalent regional tools, refer to Special Tools .

1. Clean the crankshaft (1) with solvent.
2. Thoroughly clean all oil passages and inspect for restrictions or burrs.
3. Dry the crankshaft with compressed air.
4. Perform a visual inspection of the crankshaft for damage.
5. The crankshaft position reluctor ring (1) may be replaced if damaged. Tighten the crankshaft position reluctor ring bolts to 15 N.m (11 lb ft).
6. Inspect the crankshaft journals for wear (1). The journals should be smooth, with no signs of scoring, wear, or damage.
7. Inspect the crankshaft journals for grooves or scoring (2).
8. Inspect the crankshaft journals for scratches or wear (3).
9. Inspect the crankshaft journals for pitting or imbedded bearing material (4).
10. Measure the crankshaft journals (1) for out-of-round.
11. Measure the crankshaft journals for taper.
12. Measure the crankshaft runout. Using wooden V-blocks, support the crankshaft on the front and rear journals.
13. Use the GE-7872 indicator (1) in order to measure the crankshaft runout at the front and rear intermediate journals.
14. Use the GE-7872 indicator in order to measure the runout of the crankshaft rear flange.
15. Replace the crankshaft if the measurements are not within specifications.
16. Inspect crankshaft bearings for craters or pockets (1). Flattened sections on the bearing halves also indicate fatigue.
17. Inspect the crankshaft bearings for excessive scoring or discoloration (2).
18. Inspect the crankshaft bearings for dirt or debris imbedded into the bearing material.
19. Inspect the crankshaft bearings for improper seating indicated by bright, polished sections of the bearing (3). If the lower half of the bearing is worn or damaged, both upper and lower halves should be replaced. Generally, if the lower half is suitable for use, the upper half should also be suitable for use.

Camshaft Cleaning and Inspection (LAF, LEA, or LUK)

1. Inspect the camshaft journals and lobes for wear or scoring.
2. Inspect the camshaft sprocket alignment notch for damage.
3. Inspect the camshaft cover (1) for damage or loose oil control baffles.
4. Clean the camshaft cover.
5. Wash the camshafts (2, 3) in solvent.
6. Oil the camshafts.
7. Inspect the camshaft cover for cracks or other signs of damage.

Camshaft Timing Chain and Sprocket Cleaning and Inspection

1. Inspect the timing chain guides (1, 4, 6) for cracking or wear.
2. Replace the timing chain guides if wear exceeds 1.12 mm (0.045 in) depth on the chain guide surface.
3. Inspect the timing chain tensioner shoe for wear.
4. Replace the timing chain tensioner shoe if wear exceeds 1.12 mm (0.045 in) depth on the chain guide surface.
5. Inspect the timing chain (2) and actuators (3, 8) for wear.
6. Inspect the camshaft actuator faces for signs of movement.
7. Inspect the camshaft actuator teeth and chain for signs of excessive wear, chipping, or seizure of the timing chain links.
8. Inspect the oil nozzle body (5) for collapse or cracks at the bolt boss. Discard and replace the oil nozzle body if it is damaged.
9. Verify oil nozzle oil flow with compressed air.
10. Inspect the timing chain tensioner (7) for the scoring or free movement.
11. Inspect the timing chain tensioner washer and O-ring for damage. If damaged, replace the timing chain tensioner.

Balance Shaft Cleaning and Inspection

1. Clean the balance shafts (1) in solvent.
2. Inspect the bearing surfaces on the balance shafts for scoring or unusual wear.
3. Inspect the balance shaft drive sprockets for wear, damage, or missing teeth.
4. Measure the rear bearing journals on the balance shafts, the journals should be 36.723-36.743 mm (1.4458-1.4466 in) in diameter.
5. Measure the front bearing journals on the balance shafts, the front bearing journals should be 20.020-20.000 mm (0.7881-0.7874 in) in diameter.
6. When the balance shafts have been installed in the engine block, check for smooth rotation, sticking, binding, or roughness.

Water Pump and Balance Shaft Chain and Sprocket Cleaning and Inspection

1. Inspect the balance shaft drive chain guides (3, 5, 8) for cracking or wear.
2. Replace the balance shaft drive chain guides if wear exceeds 1.12 mm (0.045 in) depth on the chain guide surface.
3. Inspect the balance shaft drive chain tensioner guide shoe for wear. Replace the balance shaft drive chain tensioner guide shoe if wear exceeds 1.12 mm (0.045 in) depth on the chain guide surface.
4. Inspect the balance shaft drive chain (7) and sprockets (2, 4) for wear.
5. Inspect the crankshaft sprocket (6) faces for signs of movement.
6. Inspect the alignment notch in the balance shaft for cracking or damage.
7. Inspect the water pump (1), crankshaft, and balance shaft sprocket teeth and chain for signs of excessive wear, chipping, or seizure of the balance shaft drive chain links.
8. Inspect the timing chain tensioner (9) for damage or wear.

Valve Cleaning and Inspection

1. Clean the valves of carbon, oil and varnish. Use a soft bristle wire brush to clean any carbon build-up from the valve head. Varnish can be removed by soaking in Parts Immersion Solvent. Refer to «Adhesives, Fluids, Lubricants, and Sealers»(ref-491134-S31490395222012073000000) .
2. Clean the valve guides.
3. Inspect the valve stem for pitting or wear (4).
4. Inspect the valve key groove for chipping or wear (5). Replace the valve if chipped or worn.
5. Inspect the valve face for burning or cracking (1). If pieces are broken off, inspect the corresponding piston and cylinder head area for damage.
6. Inspect the valve stem for burrs and scratches. Burrs and minor scratches may be removed with an oil stone.
7. Inspect the valve stem for straightness (3) and the valve head for bending or distortion using V blocks. Bent or distorted valves must be replaced.
8. Clean the deposits from the valve face. Inspect the valve face for grooving.
9. Replace the valve if the face is grooved. Valve faces cannot be machined. If worn, or damaged, the valves must be replaced.
10. Replace the valve if the valve head O.D. and chamfer (2) is worn or out of specification. Refer to «Valve and Seat Grinding»(ref-491134-S23337312222012073000000) .
11. The valves may be lightly lapped to the valve seats.
12. Replace the valve if the valve tip (6) is worn.
13. If no apparent wear, pitting, grooving, or distortion is present, perform the valve measurement and reconditioning procedure to verify valve specification. Refer to «Valve and Seat Grinding»(ref-491134-S23337312222012073000000) .

Valve Spring Cleaning and Inspection

1. Clean the valve springs in solvent.
2. Dry the valve springs with compressed air.
3. Inspect the valve springs for broken coils or coil ends.
4. Measure the valve spring tension using the EN 22738-B tester. Refer to «Engine Mechanical Specifications (LAF, LEA, or LUK)»(ref-491134-S07132447052012073000000)
5. If low valve spring load is found, replace the valve springs. DO NOT use shims to increase spring load. The use of shims can cause the valve spring to bottom out before the camshaft lobe is at peak lift.

Valve Rocker Arm Cleaning and Inspection

1. Inspect the camshaft follower roller (1) for the following: Flat spots Excessive scoring and pitting Ensure the roller spins freely
2. Inspect the camshaft follower valve tip area (2).
3. Inspect the camshaft follower stationary hydraulic lash adjuster (SHLA) pivot area (3).
4. Replace the camshaft follower or followers as necessary.

Cylinder Head and Gasket Surface Cleaning and Inspection

1. Remove the spark plugs.
2. Inspect the cylinder head gasket and mating surfaces for leaks, corrosion and blow-by. If the gasket has failed, use the following faults to determine the cause: Improper installation Loose or warped cylinder head Missing, off location or not fully seated dowel pins Corrosion in the seal area around the coolant passages Chips or debris in the cylinder head bolt holes Bolt holes in the cylinder block not drilled or tapped deep enough
3. Inspect the cylinder head gasket surface. Cylinder head may be reused if corrosion is found only outside a 4 mm (0.375 in) band around each combustion chamber (1). Replace the cylinder head if the area between the valve seats is cracked (2). Replace the cylinder head if corrosion has been found inside a 4 mm (0.375 in) band around each combustion chamber (3).
4. Clean the cylinder head bolts.
5. Remove the sealant from the rear cap mating surface with EN-28410 remover. Care must be used to avoid gouging or scraping the sealing surfaces.
6. Clean the cylinder head. Remove all varnish, soot and carbon to the bare metal.
7. Clean the valve guides.
8. Clean the threaded holes. Use a nylon bristle brush.
9. Clean the remains of the sealer from the plug holes.
10. Inspect the cylinder head bolts for damaged threads or stretching and damaged heads caused by improper use of tools.
11. Replace all suspect bolts.
12. Inspect the cylinder head for cracks. Check between the valve seats and in the exhaust ports.
13. Inspect the cylinder head deck for corrosion, sand inclusions and blow holes.
14. Using a straight edge (1) and feeler gauge (2), inspect the cylinder head deck surface for flatness. Refer to «Engine Mechanical Specifications (LAF, LEA, or LUK)»(ref-491134-S07132447052012073000000) . If the cylinder head is out of specification, replace the cylinder head. Do not machine the cylinder head.
15. Inspect all the threaded holes for damage. Threads may be reconditioned with thread inserts.
16. Inspect the sealing surfaces.
17. Inspect the cylinder head plugs and verify the oil orifice is clear and free of debris.
18. Clean the sealant from the rear cap mating surface with EN-28410 remover. Care must be used to avoid gouging or scraping the sealing surfaces.
19. Inspect the intake camshaft bearing rear cap (1) for damage.
20. Inspect the rear bearing mating surfaces for damage.
21. Inspect the camshaft bearing caps (2) for damage.
22. Inspect the camshaft front bearing caps (3) for damage.
23. Install the spark plugs. Tighten the plugs to 20 N.m (15 lb ft).

Fuel Rail and Injectors Cleaning and Inspection (LAF, LEA, or LUK)

Special Tools

1. EN-49245 Fuel Injector Seal Installer and Sizer
2. EN-49247 Injector Retaining Clip Installer

For equivalent regional tools, refer to Special Tools .

1. Disconnect the electrical connections from the fuel injectors (1).
2. Remove and discard the fuel injector retainer (2).
3. Remove the injectors (1) from the fuel rail by pulling straight out along the fuel injector axis. Slight rotation of the fuel injector is acceptable.
4. Using a suitable tool, remove the fuel injector bushing (1) by pushing straight off at the bushing tabs, indicated by the arrows. Discard the bushing.
5. Remove and discard the fuel injector O-ring (3) and plastic spacers (2).
6. Remove and discard the fuel injector seals (1).
7. Clean the exterior of the fuel rail (1) and injectors in solvent.
8. Inspect the fuel rail and components for the following conditions: Damage, debris, or restrictions to the fuel rail Damage, debris, or restrictions to the fuel ports in the fuel rail Damage to the mounting area for the fuel rail Damage to the fuel rail mounting bolts Damage to the threads on the fuel rail fuel feed fitting
9. Replace the fuel rail if any damage is found. Do not attempt to repair a fuel rail.
10. Inspect the fuel pressure sensor (3) for damage. Disconnect the harness connector (2) from the fuel pressure sensor. Remove the fuel pressure sensor. Dry the fuel pressure sensor bore in the fuel rail with a lint free cloth. The bore should be free of fuel, debris, and burrs. Lubricate the fuel rail fuel pressure sensor bore with clean engine oil. Lubricate the threads and sealing area on the fuel pressure sensor with clean engine oil. Install the fuel pressure sensor hand tight. Remove the fuel pressure sensor and re-lubricate the bore, threads, and sealing area. Install the fuel pressure sensor and tighten to 33 N.m (25 lb ft). Connect the harness connector to the fuel pressure sensor.
11. Inspect the fuel injectors for the following conditions: Damage to the fuel injector connector (7) Damage to the fuel injector harness connector Damage to the fuel injector tip (1) Damage to the tolerance ring (2)
12. Replace the fuel injector if any damage is found. Do not attempt to repair a fuel injector.
13. Install a new fuel injector bushing (3) onto the fuel injector. The bushing should seat with a distinct "snap" sound and feel.
14. Install the new white plastic spacer (4) on the fuel injector first.
15. Install the new brown plastic spacer (5) second.
16. Lubricate the new O-ring (6) with 5W30 engine oil.
17. Install the O-ring on the injector.
18. Install the fuel injectors (1) into the fuel rail. Ensure the fuel injector is fully seated in the fuel rail, and no gaps are present (2). Ensure the injector and fuel rail flanges are aligned (3)
19. Install the fuel injector retainer onto the EN-49247 installer.
20. Using EN-49247 installer, install the fuel injector retainer.
21. Inspect each installed fuel injector retainer, and ensure the retainer is fully seated on the fuel rail and fuel injector bushing flanges (1). The flanges on each side and at the top of the fuel injector should seat completely into the window on the retainer.
22. Connect the electrical connection to the fuel rail.
23. Connect the fuel rail harness connectors (1) to the fuel injectors.
24. Install EN-49245-1 long protector (3) onto the fuel injector tip, covering the first recessed area closest to the tip. Place a NEW seal (2) on EN-49245-1 long protector.
25. Using EN-49245-3 pusher (1), install the seal into the second recessed area (4) of the fuel injector.
26. Compress the seal with your fingers, then resize the seal using the EN-49245-4 sizer (5).
27. Install EN-49245-2 short protector (3) onto the fuel injector tip. Place a NEW seal (2) on EN-49245-2 short protector.
28. Using EN-49245-3 pusher (1), install the seal into the first recessed area (4) of the fuel injector.
29. Compress the seal with your fingers, then resize the seal using the EN-49245-4 sizer (5).

Intake Manifold Cleaning and Inspection (LAF, LEA, or LUK)

1. Clean the intake manifold (1) mating surfaces.
2. Inspect the intake manifold for damage.
3. Inspect the intake manifold for cracks near metallic inserts.
4. Clean and inspect the intake manifold insulator (2) for damage.
5. Inspect the crankcase ventilation passages (1) in the intake manifold face for blockage.
6. Clean the crankcase ventilation passages with compressed air if necessary. Use a maximum of 172 kPa (25 psi) of air pressure.
7. Replace the intake manifold as necessary.

Exhaust Manifold Cleaning and Inspection (LAF, LEA, or LUK)

1. Remove the oxygen sensor (3) from the manifold.
2. Clean the exhaust manifold (2) in solvent.
3. Dry the exhaust manifold with compressed air.
4. Inspect the heat shield (1) for damage.
5. Use a straight edge and a feeler gauge and measure the exhaust manifold mounting face (1) for warpage. An exhaust manifold face with warpage in excess of 0.25 mm (0.0100 in) may cause an exhaust leak and may effect OBD II system performance. Exhaust manifolds not within specifications must be replaced.

Oil Pan Cleaning and Inspection

1. Clean the oil pan mating surface.
2. Clean the oil pan (1). Remove all the sludge and the oil deposits.
3. Inspect the threads for the engine oil drain plug.
4. Inspect the oil pan for cracking near the pan rail and the transmission mounting points.
5. Inspect the oil pan for cracking resulting from impact or flying road debris.
6. Inspect the oil pan baffle and pickup screen.
7. Repair or replace the oil pan as necessary.