Intermittent
Test the vehicle under the same conditions that the customer reported in order to verify the system is operating properly.
Base Engine Misfire without Internal Engine Noises
| Cause | Correction |
|---|---|
| Abnormalities, severe cracking, bumps, or missing areas in the accessory drive belt Abnormalities in the accessory drive system and/or components may cause engine RPM variations and lead to a misfire DTC. A misfire code may be present without an actual misfire condition. | Replace the drive belt. |
| Worn, damaged, or mis-aligned accessory drive components or excessive pulley runout may lead to a misfire DTC. A misfire code may be present without an actual misfire condition. | Inspect the components, and repair or replace as required. |
| A loose or improperly installed engine flywheel or crankshaft balancer A misfire code may be present without an actual misfire condition. | Repair or replace the flywheel and/or balancer as required. |
| Restricted exhaust system A severe restriction in the exhaust flow can cause significant loss of engine performance and may set a DTC. Possible causes of restrictions include collapsed or dented pipes or plugged mufflers and/or catalytic converters. | Repair or replace as required. |
| Improperly installed or damaged vacuum hoses | Repair or replace as required. |
| Improper sealing between the intake manifold and cylinder heads or throttle body. | Replace the intake manifold, gaskets, cylinder heads, and/or throttle body as required. |
| Improperly installed or damaged MAP sensor The sealing grommet of the MAP sensor should not be torn or damaged. | Repair or replace the MAP sensor as required. |
| Damage to the MAP sensor housing | Replace the intake manifold. |
| Worn or loose rocker arms The rocker arm bearing end caps and/or needle bearings should be intact and in the proper position. | Replace the valve rocker arms as required. |
| Stuck valves Carbon buildup on the valve stem can cause the valve not to close properly. | Repair or replace as required. |
| Excessively worn or mis-aligned timing chain | Replace the timing chain and sprockets as required. |
| Worn camshaft lobes | Replace the camshaft and valve lash adjusters. |
| Excessive oil pressure A lubrication system with excessive oil pressure may lead to excessive valve lifter pump up and loss of compression. | Perform an oil pressure test. Refer to Oil Pressure Diagnosis and Testing . Repair or replace the oil pump as required. |
| Faulty cylinder head gaskets and/or cracking or other damage to the cylinder heads and engine block cooling system passages Coolant consumption may or may not cause the engine to overheat. | Inspect for spark plugs saturated by coolant. Inspect the cylinder heads, engine block, and/or head gaskets. Repair or replace as required. |
| Worn piston rings Oil consumption may or may not cause the engine to misfire. | Inspect the spark plugs for oil deposits. Inspect the cylinders for a loss of compression. Refer to Engine Compression Test . Perform cylinder leak down and compression testing to identify the cause. Repair or replace as required. |
| A damaged crankshaft reluctor wheel A damaged crankshaft reluctor wheel can result in different symptoms depending on the severity and location of the damage. Systems with electronic communications, DIS or coil per cylinder, and severe reluctor ring damage may exhibit periodic loss of crankshaft position, stop delivering a signal, and then re-sync the crankshaft position. Systems with electronic communication, DIS or coil per cylinder, and slight reluctor ring damage may exhibit no loss of crankshaft position and no misfire may occur. However, a P0300 DTC may be set. Systems with mechanical communications, high voltage switch, and severe reluctor ring damage may cause additional pulses and effect fuel and spark delivery to the point of generating a P0300 DTC or P0336. | Replace the sensor and/or crankshaft as required. |
Base Engine Misfire without Internal Engine Noises
Base Engine Misfire with Abnormal Internal Lower Engine Noises
| Cause | Correction |
|---|---|
| Abnormalities, severe cracking, bumps or missing areas in the accessory drive belt Abnormalities in the accessory drive system and/or components may cause engine RPM variations, noises similar to a faulty lower engine, and also lead to a misfire condition. A misfire code may be present without an actual misfire condition. | Replace the drive belt. |
| Worn, damaged, or mis-aligned accessory drive components or excessive pulley runout A misfire code may be present without an actual misfire condition. | Inspect the components, repair or replace as required. |
| Loose or improperly installed engine flywheel or crankshaft balancer A misfire code may be present without an actual misfire condition. | Repair or replace the flywheel and/or balancer as required. |
| Worn piston rings Oil consumption may or may not cause the engine to misfire. | Inspect the spark plugs for oil deposits. Inspect the cylinders for a loss of compression. Refer to Engine Compression Test . Perform cylinder leak down and compression testing to determine the cause. Repair or replace as required. |
| Worn crankshaft thrust bearings Severely worn thrust surfaces on the crankshaft and/or thrust bearing may permit fore and aft movement of the crankshaft, and create a DTC without an actual misfire condition. | Replace the crankshaft and bearings as required. |
Base Engine Misfire with Abnormal Internal Lower Engine Noises
Base Engine Misfire with Coolant Consumption
| Cause | Correction |
|---|---|
| Faulty cylinder head gasket and/or cracking, or other damage to the cylinder head and engine block cooling system passages. Coolant consumption may or may not cause the engine to overheat. | Inspect for spark plugs saturated by coolant. Perform a cylinder leak down test. Inspect the cylinder head and engine block for damage to the coolant passages and/or a faulty head gasket. Repair or replace as required. |
Base Engine Misfire with Coolant Consumption
Base Engine Misfire with Excessive Oil Consumption
| Cause | Correction |
|---|---|
| Worn valves, valve guides and/or valve stem oil seals | Inspect the spark plugs for oil deposits. Repair or replace as required. |
| Worn piston rings Oil consumption may or may not cause the engine to misfire. | Inspect the spark plugs for oil deposits. Inspect the cylinders for a loss of compression. Refer to Engine Compression Test . Perform cylinder leak down and compression testing to determine the cause. Repair or replace as required. |
Base Engine Misfire with Excessive Oil Consumption
Engine Will Not Crank - Crankshaft Will Not Rotate
| Cause | Correction |
|---|---|
| Seized accessory drive system component | Remove accessory drive belts. Rotate crankshaft by hand at the balancer or flywheel location. |
| Hydraulically locked cylinder Coolant/antifreeze in cylinder Oil in cylinder Fuel in cylinder | Remove spark plugs and check for fluid. Inspect for broken head gasket. Inspect for cracked engine block or cylinder head. Inspect for a sticking fuel injector. Inspect for cracked cylinder wall. |
| Seized automatic transmission torque converter | Remove the torque converter bolts. Rotate crankshaft by hand at the balancer or flywheel location. |
| Seized manual transmission | Disengage the clutch. Rotate crankshaft by hand at the balancer or flywheel location. |
| Broken timing chain and/or gears | Inspect timing chain and gears. Repair as required. |
| Seized balance shaft | Inspect balance shaft. Repair as required. |
| Material in cylinder Broken valve Piston material Foreign material Cracked cylinder wall | Inspect cylinder for damaged components and/or foreign materials. Inspect for fallen cylinder wall. Repair or replace as required. |
| Seized crankshaft or connecting rod bearings | Inspect crankshaft and connecting rod bearings. Inspect for fallen cylinder wall. Repair as required. |
| Bent or broken connecting rod | Inspect connecting rods. Repair as required. |
| Broken crankshaft | Inspect crankshaft. Repair as required. |
Engine Will Not Crank - Crankshaft Will Not Rotate
Coolant in Combustion Chamber
| Cause | Correction |
|---|---|
| DEFINITION: Excessive white smoke and/or coolant type odor coming from the exhaust pipe may indicate coolant in the combustion chamber. Low coolant levels, an inoperative cooling fan, or a faulty thermostat may lead to an "overtemperature" condition which may cause engine component damage. A slower than normal cranking speed may indicate coolant entering the combustion chamber. Refer to Engine Will Not Crank - Crankshaft Will Not Rotate . Remove the spark plugs and inspect for spark plugs saturated by coolant or coolant in the cylinder bore. Inspect by performing a cylinder leak-down test. During this test, excessive air bubbles within the coolant may indicate a faulty gasket or damaged component. Inspect by performing a cylinder compression test. Two cylinders "side-by-side" on the engine block, with low compression, may indicate a failed cylinder head gasket. Refer to Engine Compression Test . | |
| Faulty cylinder head gasket | Replace the head gasket and components as required. Refer to Cylinder Head Cleaning and Inspection (LAF, LEA, or LUK) , and Cylinder Head Replacement . |
| Warped cylinder head | Replace the cylinder head and gasket. Refer to Cylinder Head Cleaning and Inspection (LAF, LEA, or LUK) . |
| Cracked cylinder head | Replace the cylinder head and gasket. |
| Cracked cylinder liner | Replace the components as required. |
| Cylinder head or block porosity | Replace the components as required. |
Coolant in Combustion Chamber
Coolant in Engine Oil
| Cause | Correction |
|---|---|
| DEFINITION: Foamy or discolored oil or an engine oil "overfill" condition may indicate coolant entering the engine crankcase. Low coolant levels, an inoperative cooling fan, or a faulty thermostat may lead to an "overtemperature" condition which may cause engine component damage. Contaminated engine oil and oil filter should be changed. Inspect the oil for excessive foaming or an overfill condition. Oil diluted by coolant may not properly lubricate the crankshaft bearings and may lead to component damage. Refer to Lower Engine Noise, Regardless of Engine Speed . Inspect by performing a cylinder leak-down test. During this test, excessive air bubbles within the cooling system may indicate a faulty gasket or damaged component. Inspect by performing a cylinder compression test. Two cylinders "side-by-side" on the engine block with low compression may indicate a failed cylinder head gasket. Refer to Engine Compression Test . | |
| Faulty cylinder head gasket | Replace the head gasket and components as required. Refer to Cylinder Head Cleaning and Inspection (LAF, LEA, or LUK) , and Cylinder Head Replacement . |
| Warped cylinder head | Replace the cylinder head and gasket. Refer to Cylinder Head Cleaning and Inspection (LAF, LEA, or LUK) . |
| Cracked cylinder head | Replace the cylinder head and gasket. |
| Cracked cylinder liner | Replace the components as required. |
| Cylinder head or block porosity | Replace the components as required. |
Coolant in Engine Oil
Engine Support Fixture
Special Tools
- J-28467-B Universal Engine Support Fixture
- J-28467-501 Engine Support Fixture Adapters
- J-36857 Engine Lift Bracket
For equivalent regional tools, refer to Special Tools .
Measuring Cylinder Bore Diameter
- Measure the cylinder bore diameter 37 mm (1.457 in) from the deck face using the EN-8087 gauge.
- Compare your results with the «Engine Mechanical Specifications (LAF, LEA, or LUK)»(ref-491134-S07132447052012073000000) . If the cylinder diameter exceeds the specifications, the cylinder block may be oversized to 0.25 mm (0.010 in). There is only one size of oversized pistons and rings available for service. Refer to «Cylinder Boring and Honing (LAF, LEA, or LUK)»(ref-491134-S15610251892012073000000) .
Measuring Cylinder Bore Taper
- Measure the cylinder bore along the thrust surfaces, perpendicular to the crankshaft centerline, at 13 mm (0.510 in) below the deck surface (1) and record your measurement.
- Measure the cylinder bore along the thrust surfaces, perpendicular to the crankshaft centerline, at 100 mm (3.938 in) below the deck surface (2) and record your measurement.
- Calculate the difference between the 2 measurements. The result will be the cylinder taper.
- Compare your results with the «Engine Mechanical Specifications (LAF, LEA, or LUK)»(ref-491134-S07132447052012073000000) . If the cylinders exceed the specifications, the cylinder block may be oversized to 0.25 mm (0.010 in). There is only one size of oversized pistons and rings available for service. Refer to «Cylinder Boring and Honing (LAF, LEA, or LUK)»(ref-491134-S15610251892012073000000) .
Measuring Cylinder Bore Out-of-Round
- Measure both the thrust and non-thrust cylinder diameter at 13 mm (0.510 in) below the deck surface (1). Record your measurements.
- Calculate the difference between the 2 measurements. The result will indicate out-of-round at the upper end of the cylinder.
- Measure both the thrust and non-thrust cylinder diameter at 100 mm (3.938 in) below the deck surface (2). Record your measurements.
- Calculate the difference between the 2 measurements. The result will indicate out-of-round at the lower end of the cylinder.
- Compare your results with the «Engine Mechanical Specifications (LAF, LEA, or LUK)»(ref-491134-S07132447052012073000000) . If the cylinders exceed these specifications, the cylinder block may be oversized to 0.25 mm (0.010 in). There is only one size of oversized pistons and rings available for service. Refer to «Cylinder Boring and Honing (LAF, LEA, or LUK)»(ref-491134-S15610251892012073000000) .
Boring Procedure
- Measure all pistons with a micrometer to determine the cylinder bore diameter. Refer to «Engine Block Cleaning and Inspection»(ref-491134-S15828166862012073000000) .
- Before you use any type of boring bar, use a fine file and clean the top of the cylinder block, removing any dirt or burrs. If you do not check the cylinder block, the boring bar may be improperly positioned or tilted and the cylinder bore could be bored at an incorrect angle.
- Carefully follow the instructions furnished by the manufacturer regarding use of the equipment.
- When you bore the cylinders, ensure all the crankshaft bearing caps are in place. Tighten the crankshaft bearing caps to the proper torque in order to avoid distortion of the cylinder bores during final assembly.
- When you take the final cut with a boring bar, leave 0.03 mm (0.001 in) on the cylinder bore diameter for the finish honing and fit of the piston.
Honing Procedure
- When honing the cylinders, follow the manufacturer's recommendations for equipment use, cleaning, and lubrication. Use only clean, sharp stones of the proper grade for the amount of material you remove. Dull, dirty stones cut unevenly and generate excessive heat. Do not hone to final clearance with a coarse or medium-grade stone. Leave sufficient metal so that all stone marks may be removed with fine-grade stones. Perform final honing with a fine-grade stone, honing the cylinder to the proper clearance.
- During the honing operation, thoroughly clean the cylinder bore. Repeatedly check the cylinder bore for fit with the selected piston.
- When honing a cylinder for fit to an oversize piston, first perform the preliminary honing with a 100-grit stone.
- Perform final cylinder honing with a 240-grit stone and obtain a 45 degree cross hatch pattern.
- The finish marks should be clean but not sharp. The finish marks should also be free from imbedded particles and torn or folded metal.
- By measuring the selected piston at the sizing point and by adding the average of the clearance specification, you can determine the final cylinder honing dimension required.
- After final honing and before the piston is checked for fit, clean the cylinder bores with hot water and detergent. Scrub the bores with a stiff bristle brush and rinse the bores thoroughly with hot water. Do not allow any abrasive material to remain in the cylinder bores. This abrasive material may cause premature wear of the new piston rings and the cylinder bores. Abrasive material will also contaminate the engine oil and may cause premature wear of the bearings. After washing the cylinder bore, dry the bore with a clean rag.
- Perform final measurements of the piston and the cylinder bore.
- Permanently mark the top of the piston for the specific cylinder to which it has been fitted.
- Apply clean engine oil to each cylinder bore in order to prevent rusting.
Deglazing Procedure
- If the bore is glazed but otherwise serviceable, lightly break the glaze with a hone. Replace the piston rings. Refer to «Piston, Connecting Rod, and Bearing Installation (LAF, LAT, LE5, LE9, LEA, or LUK)»(ref-491134-S27373800882012073000000) .
- Using a ball type or self centering honing tool, deglaze the cylinder bore lightly. Deglazing should be done only to remove any deposits that may have formed. Use a 240-grit stone of silicone carbide, or equivalent, material when preforming the deglazing procedure. The honing stones must be clean, sharp, and straight. Move the hone slowly up and down to produce a 45 degree cross-hatch pattern. Clean the bore thoroughly with soap and water. Dry the bore. Rub clean engine oil in the bore. Re-measure the bore.
- If the cylinder bore is out of specification, the cylinder bore may be oversized to 0.25 mm (0.010 in). There is only one size of oversized pistons and rings available for service.
- If honing is not required, clean the cylinder bores with hot water and detergent. Apply clean engine oil to the bore after washing and drying the bore.
Connecting Rod Measurement
- Clean the connecting rods (1) in solvent and dry with compressed air.
- Inspect the connecting rods for the following: Signs of being twisted, bent, nicked, or cracked Scratches or abrasion on the rod bearing seating surface
- If the connecting rod bores contain minor scratches or abrasions, clean the bores in a circular direction with a light emery paper. DO NOT scrape the rod or rod cap.
- If the beam of the rod is scratched or has other damage replace the connecting rod.
- Measure the piston pin to connecting rod bore using the following procedure: Using an outside micrometer, take two measurements of the piston pin in the area of the connecting rod contact. Using an inside micrometer, measure the connecting rod piston pin bore. Subtract the piston pin diameter from the piston pin bore diameter. The clearance should not be more than 0.021 mm (0.0008 in).
- If there is excessive clearance, replace the piston pin.
- If there is still excessive clearance, replace the connecting rod.
Piston Measurement
- Clean the piston skirts and the pins with a cleaning solvent. DO NOT wire brush any part of the piston.
- Clean the piston ring grooves with a groove cleaner. Make sure oil ring holes and slots are clean.
- Inspect the pistons for the following conditions: Cracked ring lands, skirts, or pin bosses Ring grooves for nicks, burrs that may cause binding Warped or worn ring lands Eroded areas at the top of the piston (1) Scuffed or damaged skirts (2) Worn piston pin bores (3)
- Replace pistons that show any signs or damage or excessive wear.
- Measure the piston pin bore to piston pin clearances using the following procedure: Piston pin bores and pins must be free of varnish or scuffing. Use an outside micrometer to measure the piston pin in the piston contact areas. Using an inside micrometer, measure the piston pin bore. Subtract the measurement of the piston pin bore from the piston pin. The clearance should be within 0.002-0.012 mm (0.00007-0.00047 in). If the clearance is excessive, determine which component is out of specification.
- Measure the piston ring end gap using the following procedure: Place the piston ring in the area of the bore where the piston ring will travel (approximately 25 mm or 1 inch down from the deck surface). Be sure the ring is square with the cylinder bore by positioning the ring with the piston head. Measure the end gap of the piston ring with feeler gauges (1). Compare the measurements with those provided below: The top compression ring end gap should be 0.20-0.40 mm (0.0060-0.015 in). The second compression ring end gap should be 0.35-0.55 mm (0.0137-0.0216 in). The oil ring end gap should be 0.25-0.76 mm (0.0098-0.029 in). If the clearance exceeds the provided specifications, the piston rings must be replaced. Repeat the procedure for all the piston rings.
- Measure the piston ring side clearance using the following procedure: Roll the piston ring entirely around the piston ring groove. If any binding is caused by a distorted piston ring, replace the ring. With the piston ring on the piston, use feeler gauges (1) to check clearance at multiple locations. The clearance between the surface of the top piston ring and the ring land should be no greater than 0.075 mm (0.0030 in). If the clearance is greater than specifications, replace the piston ring. If the new ring does not reduce the top ring side clearance to 0.075 mm (0.0030 in) or less, install a new piston.
- The top compression ring may be installed with either side up. There is a locating dimple on the 2nd compression ring near the end for identification of the top side. Install the 2nd compression ring with the dimple facing up.
- The clearance between the surface of the second piston ring and the ring land should be no greater than 0.069 mm (0.0026 in).
- If the new ring does not reduce the clearance to 0.069 mm (0.0026 in) or less, install a new piston.
- Measure piston width using the following procedure: Using an outside micrometer (2), measure the width of the piston 14.5 mm (0.570 in) above the bottom of the piston skirt at the thrust surface perpendicular to the centerline of the piston pin. Compare the measurement of the piston to its original cylinder by subtracting the piston width from the cylinder diameter. The proper clearance specification for the piston is 0.010-0.041 mm (0.0006-0.0016 in).
- If the clearance obtained through measurement is greater than these specifications and the cylinder bores are within specification, replace the piston (1).
Piston Selection
- Inspect the engine block cylinder bore. Refer to «Engine Block Cleaning and Inspection»(ref-491134-S15828166862012073000000) .
- Inspect the piston and the piston pin.
- Use a bore gauge (1) and measure the cylinder bore diameter. Measure at a point 64 mm (2.5 in) from the top of the cylinder bore.
- Measure the bore gauge with a micrometer (1) and record the reading.
- With a micrometer (2) or caliper at a right angle to the piston (1), measure the piston 14 mm (0.570 in) from the bottom of the skirt.
- Subtract the piston diameter from the cylinder bore diameter in order to determine piston-to-bore clearance.
- For proper piston-to-bore clearance. Refer to «Engine Mechanical Specifications (LAF, LEA, or LUK)»(ref-491134-S07132447052012073000000) .
- If the proper clearance cannot be obtained, select another piston and measure for the clearances.
- If the proper fit cannot be obtained, hone the cylinder bore or replace the cylinder block.
- When the piston-to-cylinder bore clearance is within specifications, mark the top of the piston using a permanent marker for installation to the proper cylinder. Refer to «Separating Parts»(ref-491134-S16512735672012073000000) .
Valve Guide Measurement
- Measure the valve stem (1)-to-guide (2) clearance. Excessive valve stem-to-guide clearance may cause an excessive oil consumption and may also cause a valve to break. Insufficient clearance will result in noisy and sticky functioning of the valve and will disturb the engine assembly smoothness.
- Clamp the GE 7872 dial indicator to the cylinder head at the camshaft cover rail.
- Locate the dial indicator so that the movement of the valve stem from side to side, crossways to the cylinder head, will cause a direct movement of the indicator stem. The dial indicator stem must contact the side of the valve stem just above the valve guide.
- Drop the valve head about 0.064 mm (0.0025 in) off the valve seat.
- Use light pressure when moving the valve stem from side to side in order to obtain a clearance reading. Refer to «Engine Mechanical Specifications (LAF, LEA, or LUK)»(ref-491134-S07132447052012073000000) for proper clearance.
- If the clearance for the valve is greater than specifications and a new standard diameter valve stem will not bring the clearance within specifications, replace the cylinder head.
Valve Seat Width Measurement Procedure
- Measure the valve seat width in the cylinder head using a proper scale.
- Measure the seat width (b) on the valve face (1) using a proper scale.
- Compare your measurements with the specifications listed in «Engine Mechanical Specifications (LAF, LEA, or LUK)»(ref-491134-S07132447052012073000000) .
- If the seat widths are acceptable, check the valve seat roundness using the Valve Seat Roundness Measurement Procedure.
- If the seat width is not acceptable, you must grind the valve seat using the Valve and Seat Reconditioning Procedure to bring the width back into specification. Proper valve seat width is critical to providing the correct amount of valve heat dissipation.
Valve Seat Roundness Measurement Procedure
- Measure the valve seat roundness using a dial indicator attached to a tapered pilot installed in the guide. The pilot should have a slight bind when installed in the guide.
- Compare your measurements with the specifications listed in «Engine Mechanical Specifications (LAF, LEA, or LUK)»(ref-491134-S07132447052012073000000) .
- If the valve seat exceeds the roundness specification, you must grind the valve and valve seat using the Valve and Seat Reconditioning Procedure.
- If new valves are being used, the valve seat roundness must be within 0.05 mm (0.002 in).
Valve Head O.D. and Chamfer Measurement Procedure
- Measure the valve head O.D. and chamfer (a) using an appropriate scale. Refer to «Engine Mechanical Specifications (LAF, LEA, or LUK)»(ref-491134-S07132447052012073000000) .
- If the valve head O.D. and chamfer is within specification, test the valve (1) for seat concentricity using the Valve-to-Seat Concentricity Measurement Procedure. Reinspect the valve head O.D. and chamfer after completing the concentricity measurement if valve seat reconditioning is performed.
Valve-to-Seat Concentricity Measurement Procedure
- Coat the valve face (3) lightly with blue dye (1).
- Install the valve in the cylinder head.
- Turn the valve against the seat with enough pressure to wear off the dye.
- Remove the valve from the cylinder head.
- Inspect the valve face. If the valve face is concentric, providing a proper seal, with the valve stem, a continuous mark (2) will be made around the entire face. NOTE: The wear mark MUST be at least 0.5 mm (0.020 in) from the outer diameter, the margin (a), of the valve. If the wear mark is too close to the margin, the seat must be reconditioned to move the contact area away from the margin. NOTE: Do not grind or condition the intake valve. If the intake valve is out of specification, replace the valve. If the face is not concentric with the stem, the mark will NOT be continuous around the valve face. The valve should be refaced or replaced and the seat must be reconditioned using the Valve and Seat Reconditioning Procedure.
Valve and Seat Reconditioning Procedure
- Grind the valve seating surface (a) to the proper angle specification (2) listed in «Engine Mechanical Specifications (LAF, LEA, or LUK)»(ref-491134-S07132447052012073000000) .
- Grind the valve relief surface to the proper angle specification (1) listed in «Engine Mechanical Specifications (LAF, LEA, or LUK)»(ref-491134-S07132447052012073000000) , to correctly position the valve seating surface (a) to the valve.
- Grind the valve undercut surface to the proper angle specification (3) listed in «Engine Mechanical Specifications (LAF, LEA, or LUK)»(ref-491134-S07132447052012073000000) ,, to narrow the valve seating surface width (a) to the specifications listed in «Engine Mechanical Specifications (LAF, LEA, or LUK)»(ref-491134-S07132447052012073000000) .
- Replace the intake valve if it is out of specification. Refer to «Engine Mechanical Specifications (LAF, LEA, or LUK)»(ref-491134-S07132447052012073000000) .
- If the original exhaust valve is being used, grind the valve to the specifications listed in «Engine Mechanical Specifications (LAF, LEA, or LUK)»(ref-491134-S07132447052012073000000) . Measure the valve head O.D. and chamfer again after grinding using the Valve Head O.D. and Chamfer Measurement Procedure. Replace the exhaust valve if it is out of specification. New valves do not require grinding.
- When grinding the valves and seats, grind off as little material as possible. Cutting valve seat results in lowering the valve spring pressure.
- Install the valve in the cylinder head. If you are using refaced exhaust valves, lap the valves into the seats with a fine grinding compound. The refacing and re-seating operations should leave the refinished surfaces smooth and true so that minimal lapping is required. Excessive lapping will groove the valve face and prevent a good seat when hot. Be sure to clean any remaining lapping compound from the valve and seat with solvent and compressed air prior to final assembly.
- After obtaining the proper valve seat width in the cylinder head, you must re-measure the valve stem height using the Valve Stem Height Measurement Procedure.
- If the valve stem height is acceptable, test the seats for concentricity using the Valve-to-Seat Concentricity Measurement Procedure.
Valve Stem Height Measurement Procedure
- Install the valve (1) into the valve guide in the cylinder head (2).
- Ensure the valve is seated to the cylinder head valve seat.
- Install the valve stem oil seal.
- Install the valve spring retainer and valve stem locks.
- Measure the distance (a) between the valve seal lip to the bottom of the valve spring retainer. Refer to «Engine Mechanical Specifications (LAF, LEA, or LUK)»(ref-491134-S07132447052012073000000) .
- If the maximum height specification is exceeded, a new valve should be installed and the valve stem height re-measured.
- If the valve stem height still exceeds the maximum height specification, the cylinder head must be replaced.
Thread Repair
Special Tools
EN 42385-850 Thread Repair Kit
For equivalent regional tools, refer to Special Tools .
Scheme 74
The thread repair process involves a solid, thin walled, self-locking, carbon steel, bushing type insert (1). During the bushing installation process, the driver tool expands the bottom external threads of the insert into the base material (2). This action mechanically locks the insert in place. Also, when installed to the proper depth, the flange of the insert will be seated against the counterbore of the repaired hole.
- Drill out the threads of the damaged hole (1). M6 inserts require a minimum drill depth of 15 mm (0.59 in). M8 inserts require a minimum drill depth of 20 mm (0.79 in). M10 inserts require a minimum drill depth of 23.5 mm (0.93 in).
- Using compressed air, clean out any chips.
- Counterbore the hole to the full depth permitted by the tool (1).
- Using compressed air, clean out any chips.
- Using a tap wrench (2), tap the threads of the drilled hole. M6 inserts require a minimum tap depth of 15 mm (0.59 in). M8 inserts require a minimum tap depth of 20 mm (0.79 in). M10 inserts require a minimum tap depth of 23.5 mm (0.93 in).
- Using compressed air, clean out any chips.
- Spray cleaner into the hole. Refer to «Adhesives, Fluids, Lubricants, and Sealers»(ref-491134-S31490395222012073000000) .
- Using compressed air, clean any cutting oil and chips out of the hole.
- Lubricate the threads of the installer tool (2) with the driver oil (1).
- Install the insert (2) onto the driver tool (1).
- Apply threadlock LOCTITE™ 277, EN 42385-109 (1) loctite, or equivalent to the insert OD threads (2).
- Install the insert (2) into the hole. Install the insert until the flange of the insert contacts the counterbored surface. Continue to rotate the installer tool (1) through the insert. The installer tool will tighten up before screwing completely through the insert. This is acceptable. You are forming the bottom threads of the insert and mechanically locking the insert to the base material threads.
- Inspect the insert for proper installation into the hole. A properly installed insert (1) will be either flush or slightly below flush with the surface of the base material (2).
Cylinder Head Bolt Hole Thread Repair
- The cylinder head bolt hole thread repair kit consists of the following items: Drill (1) Tap (2) Installer (3) Sleeve (4) Alignment Pin (5) Bushing (6) Bolts (7) Fixture Plate (8)
- Install the fixture plate (3), bolts (1), and bushing (2) onto the engine block deck. Position the fixture plate and bushing over the hole that is to be repaired (4).
- Position the alignment pin (1) through the bushing and into the hole.
- With the alignment pin in the desired hole, tighten the fixture retaining bolts (2).
- Remove the alignment pin from the hole.
- Install the sleeve (2) onto the drill (1), if required.
- Drill out the threads of the damaged hole. Drill the hole until the stop collar of the drill bit or the sleeve contacts the bushing.
- Using compressed air, clean out any chips.
- Using a tap wrench, tap the threads of the drilled hole.
- Using a TAP wrench, tap the threads of the drilled hole. In order to tap the new threads to the proper depth, rotate the tap into the hole until the mark (3) on the tap align with the top of the drill bushing (2).
- Remove the fixture plate (1), bushing (2), and bolts.
- Using compressed air, clean out any chips.
- Spray cleaner into the hole. Refer to «Adhesives, Fluids, Lubricants, and Sealers»(ref-491134-S31490395222012073000000) .
- Using compressed air, clean any cutting oil and chips out of the hole.
- Lubricate the threads of the installer tool (2) with the driver oil (1).
- Install the insert (2) onto the driver tool (1).
- Apply threadlock LOCTITE™ 277, EN 42385-109 loctite (1), or equivalent to the insert OD threads (2).
- Install the insert and driver (1) into the hole. Rotate the driver tool until the mark on the tool aligns with the deck surface of the engine block. The installer tool will tighten up before screwing completely through the insert. This is acceptable. You are forming the bottom threads of the insert and mechanically locking the insert to the base material threads.
Main Cap Bolt Hole Thread Repair
- The main cap bolt hole thread repair kit consists of the following items: Drill (1) Tap (2) Installer (3) Fixture Plate (4) Long Bolts (5) Short Bolts (6) Alignment Pin (7) Bushing (8)
- Remove the alignment dowel pins from the holes (1-4), if necessary.
- Install the fixture plate, bolt, and bushing, onto the engine block. Position the fixture plate and bushing over the hole that is to be repaired.
- Position the alignment pin in the desired hole and tighten the fixture retaining bolts.
- Drill out the damaged hole.
- Using compressed air, clean out any chips.
- Using a tap wrench, tap the threads of the drilled hole. In order to tap the new threads to the proper depth, rotate the tap into the hole until the mark (3) on the tap aligns with the top of the bushing (2).
- Using compressed air, clean out any chips.
- Spray cleaner into the hole. Refer to «Adhesives, Fluids, Lubricants, and Sealers»(ref-491134-S31490395222012073000000) .
- Using compressed air, clean any cutting oil and chips out of the hole.
- Lubricate the threads of the installer tool (2) with the driver oil (1).
- Install the insert (2) onto the driver tool (1).
- Apply threadlock LOCTITE™ 277, EN 42385-109 (1), or equivalent to the insert OD threads (2).
- Install the insert and driver through the bushing (2), fixture plate (1) and into the hole. Rotate the driver tool until the mark on the tool (3) aligns with the top of the bushing (2). The installer tool will tighten up before screwing completely through the insert. This is acceptable. You are forming the bottom threads of the insert and mechanically locking the insert to the base material threads.
- Remove the driver, bushing (2), fixture plate (1), and bolts.
- Install the alignment dowel pins in holes (1-4), if necessary.
Balance Shaft to Engine Timing (LAF, LEA, or LUK)
- Install the balance shaft drive sprocket.
- Install the balance shaft drive chain with the colored links lined up on with the marks on the balance shaft drive sprockets and the crankshaft sprocket. There are three colored links on the chain. Two links are of matching colors, and one link is of a unique color. Use the following procedure to line up the links with the sprockets: Orient the chain so that the colored links are visible.
- Place the uniquely colored link (1) so that it lines up with the timing mark on the intake side balance shaft sprocket.
- Working clockwise around the chain, place the first matching colored link (2) in line with the timing mark on the crankshaft drive sprocket, approximately 6 o'clock position on the crank sprocket.
- Place the chain (3) on the water pump drive sprocket. The alignment is not critical.
- Align the last matching colored link (4) with the timing mark on the exhaust side balance shaft drive sprocket.
Engine Prelubing
Note. This procedure is not used in Europe.
Special Tools
EN-45299 Engine Preluber
For equivalent regional tools, refer to Special Tools .
- Remove the oil pressure switch.
- Install the M12 x 1.75 adapter (1) P/N 509376.
- Install the flexible hose to the adapter and open the valve.
- Pump the handle on the EN-45299 preluber (1) in order to flow a minimum of 1-1.9 liters (1-2 quarts) of engine oil. Observe the flow of engine oil through the flexible hose and into the engine assembly.
- Close the valve and remove the flexible hose and adapter from the engine.
- Install the oil pressure switch to the engine and tighten to 22 N.m (16 lb ft).
- Top-off the engine oil to the proper level.
Cleanliness and Care
An automobile engine is a combination of many machined, honed, polished, and lapped surfaces with tolerances that are measured in ten thousandths of an inch. When any internal engine parts are serviced, care and cleanliness are important. A liberal coating of engine oil should be applied to friction areas during assembly to protect and lubricate the surfaces during initial operation. Throughout this section, it should be understood that proper cleaning and protection of machined surfaces and friction areas are part of the repair procedure. This is considered standard shop practice even if not specifically stated.
When valve train components are removed for service, they should be retained in order. At the time of installation, they should be installed in the same locations and with the same mating surfaces as when removed.
Separating Parts
Note. Disassembly of the piston, press fit design piston pin, and connecting rod may create scoring or damage to the piston pin and piston pin bore. If the piston, pin, and connecting rod have been disassembled, replace the components as an assembly. Many internal engine components will develop specific wear patterns on their friction surfaces. When disassembling the engine, internal components MUST be separated, marked, or organized in a way to ensure installation to their original location and position.
Separate, mark, or organize the following components
- Piston and the piston pin
- Piston to the specific cylinder bore
- Piston rings to the piston
- Connecting rod to the crankshaft journal
- Connecting rod to the bearing cap A paint stick or etching/engraving type tool are recommended. Stamping the connecting rod or cap near the bearing bore may affect component geometry.
- Crankshaft main and connecting rod bearings
- Camshaft and valve lash adjusters
- Valve lash adjusters, lash adjuster guides, pushrods and rocker arm assemblies
- Valve to the valve guide
- Valve spring and shim to the cylinder head location
- Engine block main bearing cap location and direction
- Oil pump drive and driven gears
Gasket Reuse and Applying Sealants
- Do not reuse any gasket unless specified.
- Gaskets that can be reused will be identified in the service procedure.
- Do not apply sealant to any gasket or sealing surface unless called out in the service information.
Separating Components
- Use a rubber mallet to separate components.
- Bump the part sideways to loosen the components.
- Bumping should be done at bends or reinforced areas to prevent distortion of parts.
Cleaning Gasket Surfaces
- Remove all gasket and sealing material from the part using the EN-28410 remover or equivalent.
- Care must be used to avoid gouging or scraping the sealing surfaces.
- Do not use any other method or technique to remove sealant or gasket material from a part.
- Do not use abrasive pads, sand paper, or power tools to clean the gasket surfaces. These methods of cleaning can cause damage to the component sealing surfaces. Abrasive pads also produce a fine grit that the oil filter cannot remove from the oil. This grit is abrasive and has been known to cause internal engine damage.
Use of Room Temperature Vulcanizing (RTV) and Anaerobic Sealant
Three types of sealer are commonly used in engines. These are RTV sealer, anaerobic gasket eliminator sealer, and pipe joint compound. The correct sealer and amount must be used in the proper location to prevent oil leaks. DO NOT interchange the 3 types of sealers. Use only the specific sealer or the equivalent as recommended in the service procedure.
Room Temperature Vulcanizing (RTV) Sealer
- RTV sealant hardens when exposed to air. This type sealer is used where 2 rigid parts, such as the lower crankcase and the engine block, are assembled together.
- Do not use RTV sealant in areas where extreme temperatures are expected. These areas include: exhaust manifold, head gasket, or other surfaces where a gasket eliminator is specified.
- Follow all safety recommendations and directions that are on the container. To remove the sealant or the gasket material, refer to «Replacing Engine Gaskets»(ref-491134-S17004802152012073000000) .
- Apply RTV to a clean surface. Use a bead size as specified in the procedure. Run the bead to the inside of any bolt holes. Do not allow the sealer to enter any blind threaded holes, as it may prevent the bolt from clamping properly or cause damage when the bolt is tightened.
- Assemble components while RTV is still wet, within 3 minutes. Do not wait for RTV to skin over.
- Tighten bolts to specifications. Do not overtighten.
Anaerobic Sealer
- Anaerobic gasket eliminator hardens in the absence of air. This type sealer is used where two rigid parts (such as castings) are assembled together. When two rigid parts are disassembled and no sealer or gasket is readily noticeable, the parts were probably assembled using a gasket eliminator.
- Follow all safety recommendations and directions that are on the container. To remove the sealant or the gasket material, refer to «Replacing Engine Gaskets»(ref-491134-S17004802152012073000000) .
- Apply a continuous bead of gasket eliminator to one flange. Surfaces to be resealed must be clean and dry.
- Spread the sealer evenly with your finger to get a uniform coating on the sealing surface.
- Do not allow the sealer to enter any blind threaded holes, as it may prevent the bolt from clamping properly or cause damage when tightened.
- Tighten bolts to specifications. Do not overtighten.
- After properly tightening the fasteners, remove the excess sealer from the outside of the joint.
Pipe Joint Compound
- Pipe joint compound is a pliable sealer that does not completely harden.
- Do not use pipe joint compound in areas where extreme temperatures are expected. These areas include: exhaust manifold, head gasket, or other surfaces where gasket eliminator is specified.
- Follow all safety recommendations and directions that are on the container. To remove the sealant or the gasket material, refer to «Replacing Engine Gaskets»(ref-491134-S17004802152012073000000) .
- Apply the pipe joint compound to a clean surface. Use a bead size or quantity as specified in the procedure. Run the bead to the inside of any bolt holes. Do not allow the sealer to enter any blind threaded holes, as it may prevent the bolt from clamping properly or cause component damage when the bolt is tightened.
- Apply a continuous bead of pipe joint compound to one sealing surface. Sealing surfaces to be resealed must be clean and dry.
- Tighten the bolts to specifications. Do not overtighten.
Tools and Equipment
Special tools are listed and illustrated throughout this section with a complete listing at the end of the section. These tools, or their equivalents, are specially designed to quickly and safely accomplish the operations for which they are intended. The use of these special tools will also minimize possible damage to engine components. Some precision measuring tools are required for inspection of certain critical components. Torque wrenches and a torque angle meter are necessary for the proper tightening of various fasteners.
To properly service the engine assembly, the following items should be readily available
- Approved eye protection and safety gloves
- A clean, well lit, work area
- A suitable parts cleaning tank
- A compressed air supply
- Trays or storage containers to keep parts and fasteners organized
- An adequate set of hand tools
- Approved engine repair stand
- An approved engine lifting device that will adequately support the weight of the components