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SECTION 1A

GENERAL ENGINE INFORMATION

DIAGNOSIS

Compression Test

Important : Disconnect the Crankshaft Position (CKP) Sensor connector to disable the fuel and the ignition systems.

Test the compression pressure for each cylinder. Low compression pressure may be the fault of the valves or the pistons. The following conditions should be considered when you check the cylinder compression:
  1. Place approximately three squirts of oil from a plunger- type oiler into each spark plug port.
  2. Place approximately three squirts of oil from a plunger- type oiler into each spark plug port.
  3. Insert the engine compression gauge into each spark plug port.
  4. Insert the engine compression gauge into each spark plug port.
  5. Crank test each cylinder with four to five compression strokes using the starter motor.
  6. Crank test each cylinder with four to five compression strokes using the starter motor.
  7. The lowest reading should not be less than 70% of the highest reading. The compression gauge reading should not be less than 689 kPa (100 psi) for any of the cylinders.
  8. The lowest reading should not be less than 70% of the highest reading. The compression gauge reading should not be less than 689 kPa (100 psi) for any of the cylinders.
  9. Examine the gauge readings obtained after the four "puffs" per cylinder are obtained from cranking the starter motor. The readings are explained in the following descriptions:
  10. Examine the gauge readings obtained after the four "puffs" per cylinder are obtained from cranking the starter motor. The readings are explained in the following descriptions:

Oil Pressure Test

Step Action Value(s) Yes No
1
Is the oil pressure warning lamp on?
-
Go to Step 2
System OK
2
Check the oil level in the crankcase.
Is the oil level low?
-
Go to Step 3
Go to Step 4
3
Add oil so that the oil level is up to the fullmark on the indicator.
Is the repair complete?
-
Go to Step 1
-
4
Check the idle speed.
Is the idle speed below the specified value ?
825 rpm
Go to Step 5
Go to Step 6
5
Increase the idle speed.
Is the speed increased?
-
Go to Step 1
-
6
Inspect the oil pressure switch.
Is the oil pressure switch incorrect or malfunctioning?
-
Go to Step 7
Go to Step 8
7
Install a new oil pressure switch.
Is the repair complete?
-
Go to Step 1
-
8
Inspect the oil pressure gauge.
Is the oil pressure gauge incorrect or malfunctioning?
-
Go to Step 9
Go to Step 10
9
Install a new oil pressure gauge.
Is the repair complete?
-
Go to Step 1
-
10
Inspect the engine oil.
Is the engine oil in the crankcase diluted or of the improper viscosity?
-
Go to Step 11
Go to Step 12
11
Install new engine oil of the proper viscosity for the expected temperatures.
Is the repair complete?
-
Go to Step 1
-
12
Inspect the oil pump.
Is the pump worn or dirty?
-
Go to Step 13
Go to Step 14
13
Replace the oil pump.
Is the repair complete?
-
Go to Step 1
-
14
Inspect the oil filter.
Is the oil filter plugged?
-
Go to Step 15
Go to Step 16
15
Install a new oil filter.
Is the repair complete?
-
Go to Step 1
-
16
Inspect the oil pickup screen.
Is the oil pickup screen loose or plugged?
-
Go to Step 17
Go to Step 18
17
Tighten or replace the oil pickup screen, as necessary.
Is the repair complete?
-
Go to Step 1
-
18
Inspect the oil pickup tube.
Are there any holes in the oil pickup tube?
-
Go to Step 19
Go to Step 20
19
Replace the oil pickup tube.
Is the repair complete?
-
Go to Step 1
-
20
Inspect the bearing clearances.
Are the bearing clearances more than the specified values?
Crankshaft 0.026 ~0.046 mm (0.0010~0.0018 in.)
Connecting Rod 0.019 ~ 0.070 mm (0.0007 ~ 0.0027 in.)
Go to Step 21
Go to Step 22
21
Replace the bearing, if necessary.
Is the repair complete?
-
Go to Step 1
-
22
Inspect the oil galleries.
Are the oil galleries cracked, porous, or plugged?
-
Go to Step 23
Go to Step 24
23
Repair or replace the engine block.
Is the repair complete?
-
Go to Step 1
-
24
Inspect the gallery plugs.
Are any of the gallery plugs missing or installed improperly?
-
Go to Step 25
Go to Step 26
25
Install the plugs or repair, as necessary.
Is the repair complete?
-
Go to Step 1
-
26
Inspect the camshaft.
Is the camshaft worn or is there evidence of poor machining?
-
Go to Step 27
System OK
27
Replace the camshaft.
Is the repair complete?
-
Go to Step 1
-

Oil Leak Diagnosis

Most fluid oil leaks are easily located and repaired by visually finding the leak and replacing or repairing the necessary parts. On some occasions, a fluid leak may be difficult to locate or repair. The following procedures may help you in locating and repairing most leaks.

Finding the Leak:

  1. Identify the fluid. Determine whether it is engine oil, automatic transmission fluid, power steering fluid, etc.
  2. Identify where the fluid is leaking from.
    1. After running the vehicle at normal operating temperature, park the vehicle over a large sheet of paper.
    2. Wait a few minutes.
    3. Find the approximate location of the leak by the drippings on the paper.
  3. Visually check around the suspected component. Check around all the gasket mating surfaces for leaks. A mirror is useful for finding leaks in areas that are hard to reach.
  4. If the leak still cannot be found, it may be necessary to clean the suspected area with a degreaser, steam, or spray solvent.
    1. Thoroughly clean the area.
    2. Dry the area.
    3. Operate the vehicle for several miles at normal operating temperature and varying speeds.
    4. After operating the vehicle, visually check the suspected component.
    5. If you still cannot locate the leak, try using the powder or black light and dye method.

Powder Method:

  1. Clean the suspected area.
  2. Apply an aerosol-type powder, (such as foot powder), to the suspected area.
  3. Operate the vehicle under normal operating conditions.
  4. Visually inspect the suspected component. Trace the leak path over the white powder surface to the source.

Black Light and Dye Method:

A dye and light kit is available for finding leaks. Refer to the manufacturer's directions when using the kit.
  1. Pour the specified amount of dye into the engine oil fill tube.
  2. Operate the vehicle under normal operating conditions as directed in the kit.
  3. Direct the light toward the suspected area. The dyed fluid will appear as a yellow path leading to the source.

Repairing the Leak

Once the origin of the leak has been pinpointed and traced back to its source, the cause of the leak must be determined in order for it to be repaired properly. If a gasket is replaced, but the sealing flange is bent, the new gasket will not repair the leak. The bent flange must be repaired also. Before attempting to repair a leak, check for the following conditions and correct them as they may cause a leak.

Gaskets:

Seals:

Knock Diagnosis

Definition for Knock

Engine knock refers to various types of engine noise. Heavy knock is usually very loud and the result of broken or excessively worn internal engine components. Light knock is a noticeable noise, but not as loud. Light knock can be caused by worn internal engine components. Loose or broken external engine components can also cause heavy or light knock.

Engine Knocks Cold and Continues for Two-Three Minutes and/or Knock Increases with Engine Torque

Step Action Value(s) Yes No
1
Does the engine knock when it is cold and continue for two to three minutes or does the knock increase with torque?
-
Go to Step 2
System OK
2
Inspect the flywheel.
Is the flywheel contacting the splash shield?
-
Go to Step 3
Go to Step 4
3
Reposition the splash shield.
Is the repair complete?
-
Go to Step 1
-
4
Inspect the balancer and the drive pulleys.
Is either the balancer or the drive pulleys loose or broken?
-
Go to Step 5
Go to Step 6
5
Tighten or replace the balancer or the drive pulleys.
Is the repair complete?
-
Go to Step 1
-
6
Inspect the piston-to-bore clearance.
Is the clearance more than the specified value?
0.030 mm (0.001 in.)
Go to Step 7
Go to Step 8
7
1. Rebore the cylinder and hone to size.
2. Replace the piston.
Is the repair complete?*
-
Go to Step 1
-
8
Inspect the connecting rod.
Is the connecting rod bent?
-
Go to Step 9
System OK
9
Replace the connecting rod.
Is the repair complete?
-
Go to Step 1
-
* Cold engine piston knock usually disappears when the cylinder is grounded out. Cold engine piston knock, which disappears in about 1.5 minutes, is considered acceptable.

Heavy Knock Hot with Torque Applied

Step Action Value(s) Yes No
1
Is there a heavy knock when the engine is hot and torque is applied?
-
Go to Step 2
System OK
2
Inspect the balancer and the pulley hub.
Is the balancer or the pulley hub broken?
-
Go to Step 3
Go to Step 4
3
Replace the broken balancer or the pulley hub.
Is the repair complete?
-
Go to Step 1
-
4
Inspect the torque converter bolts.
Are the bolts tightened to specified value?
45 N•m
(33 lb-ft)
Go to Step 5
Go to Step 6
5
Tighten the torque converter bolts.
Is the repair complete?
-
Go to Step 1
-
6
Inspect the accessory belts.
Are the belts too tight or nicked?
-
Go to Step 7
Go to Step 8
7
Replace and/or tension the belts to specifications, as necessary.
Is the repair complete?
-
Go to Step 1
-
8
Inspect the exhaust system.
Is the system grounded?
-
Go to Step 9
Go to Step 10
9
Reposition the system, as necessary.
Is the repair complete?
-
Go to Step 1
-
10
Inspect the flywheel.
Is the flywheel cracked?
-
Go to Step 11
Go to Step 12
11
Replace the flywheel.
Is the repair complete?
-
Go to Step 1
-
12
Inspect the main bearing clearance.
Is the clearance more than the specified value?
0.026~0.046 mm (0.0010~ 0.0018 in.)
Go to Step 13
Go to Step 14
13
Replace the main bearings, as necessary.
Is the repair complete?
-
Go to Step 1
-
14
Inspect the rod bearing clearance.
Is the clearance more than the specified value?
0.019 ~ 0.070 mm (0.0007 ~ 0.0028 in.)
Go to Step 15
System OK
15
Replace the rod bearings, as necessary.
Is the repair complete?
-
Go to Step 1
-

Light Knock Hot

Step Action Value(s) Yes No
1
Is there a light knock when the engine is hot?
-
Go to Step 2
System OK
2
Is detonation or spark knock evident?
-
Go to Step 3
Go to Step 4
3
Check the engine timing and the fuel quality.
Was the problem found?
-
Go to Step 1
-
4
Inspect the torque converter bolts.
Are the bolts tightened to the specified value?
45 N•m (33 lb-ft)
Go to Step 5
Go to Step 6
5
Tighten the torque converter bolts.
Is the repair complete?
-
Go to Step 1
-
6
Inspect the manifold.
Is there an exhaust leak at the manifold?
-
Go to Step 7
Go to Step 8
7
Tighten the bolts or replace the gasket.
Is the repair complete?
-
Go to Step 1
-
8
Check the rod bearing clearance.
Is the clearance within the specified value?
0.019 ~ 0.070 mm (0.0007 ~ 0.0028 in.)
Go to Step 9
System OK
9
Replace the rod bearings, as necessary.
Is the repair complete?
-
Go to Step 1
-

Knocks During Initial Start-Up But Last Only a Few Seconds

Step Action Value(s) Yes No
1
Does the engine knock during initial start-up but last only a few seconds?
-
Go to Step 2
System OK
2
Check the engine oil.
Is the proper viscosity oil used in the crankcase?
-
Go to Step 4
Go to Step 3
3
Install oil of the proper viscosity for the expected seasonal temperatures.
Is the repair complete?
-
Go to Step 1
-
4
Inspect the hydraulic lifters.
Is there evidence of hydraulic lifter bleed-down?
-
Go to Step 5
Go to Step 6
5
Clean, test and replace the lifters, as necessary.
Is the repair complete?*
-
Go to Step 1
-
6
Inspect the crankshaft end clearance.
Is the clearance more than specified value?
0.1 mm (0.0039 in.)
Go to Step 7
Go to Step 8
7
Replace the crankshaft thrust bearing.
Is the repair complete?
-
Go to Step 1
-
8
Inspect the front main bearing clearance.
Is the clearance more than the specified value?
0.026~0.046 mm (0.0010~ 0.0018 in.)
Go to Step 9
System OK
9
Replace the worn parts of the front main bearing.
Is the repair complete?
-
Go to Step 1
-
* When the engine is stopped, some valves will be open. Spring pressure against the lifters will tend to bleed lifter down. Attempts to repair this should be made only if the problem is consistent.
An engine that is only operated for short periods between start-ups may have lifter noise that lasts for a few minutes. This is a normal condition.

Knocks at Idle Hot

Step Action Value(s) Yes No
1
Does the engine knock at idle when hot?
-
Go to Step 2
System OK
2
Inspect the drive belts.
Are the belts loose or worn?
-
Go to Step 3
Go to Step 4
3
Tension or replace the belts, as necessary.
Is the repair complete?
-
Go to Step 1
-
4
Inspect the A/C compressor and the generator.
Is either the compressor or the generator faulty?
-
Go to Step 5
Go to Step 6
5
Replace the faulty A/C compressor or the generator.
Is the repair complete?
-
Go to Step 1
-
6
Inspect the valve train.
Are valve train components faulty?
-
Go to Step 7
Go to Step 8
7
Replace the faulty valve train components.
Is the repair complete?
-
Go to Step 1
-
8
Check the engine oil.
Is the proper viscosity oil used in the crankcase?
-
Go to Step 10
Go to Step 9
9
Install oil of the proper viscosity for the expected seasonal temperatures.
Is the repair complete?
-
Go to Step 1
-
10
Inspect the piston pin clearance.
Is the clearance more than the specified value?
0.020 mm (0.0008 in.)
Go to Step 11
Go to Step 12
11
Replace the piston and the pin.
Is the repair complete?
-
Go to Step 1
-
12
Check the connecting rod alignment.
Is the alignment faulty?
-
Go to Step 13
Go to Step 14
13
Check and replace rods, as necessary.
Is the repair complete?
-
Go to Step 1
-
14
Inspect the piston-to-bore clearance.
Is the clearance within the specified value?
0.030 mm (0.0012 in.)
Go to Step 16
Go to Step 15
15
Hone the bore and fit a new piston.
Is the repair complete?
 -
Go to Step 1
-
16
Inspect the crankshaft balancer.
Is the balancer loose?
-
Go to Step 17
Go to Step 18
17
Torque or replace worn parts.
Is the repair complete?
-
Go to Step 1
-
18
Check the piston pin offset.
Is the offset at the specified value?
0.5 ± 0.1 mm (0.020 ~ 0.003 in.) Toward Thrust
Go to Step 19
System OK
19
Install the correct piston.
Is the repair complete?
-
Go to Step 1
-

Noise Diagnosis

Main Bearing Noise

Step Action Value(s) Yes No
1
Are dull thuds or knocks heard with every engine revolution?
-
Go to Step 2
System OK
2
Check the oil pump pressure.
Is the oil pump pressure low?
-
Go to Oil Pressure Test
Go to Step 3
3
Inspect the crankshaft end play.
Does the crankshaft end play exceed the specified value?
0.1 mm (0.0039 in.)
Go to Crankshaft Replacement Procedure
Go to Step 4
4
Inspect the crankshaft journals.
Are the crankshaft journals out-of-round?
0.004 mm (0.0002 in.) max.
Go to Crankshaft Replacement Procedure
Go to Step 5
5
Inspect the belt tension.
Does the belt tension exceed the specified value?
-
Go to Timing Belt Replacement Procedure
Go to Step 6
6
Inspect the crankshaft pulley.
Is the crankshaft pulley loose?
-
Go to Crankshaft Replacement Procedure
System OK

Connecting Rod Bearing Noise Symptom

Step Action Value(s) Yes No
1
Is a knock noise heard under all engine speeds?
-
Go to Step 2
System OK
2
Inspect the crankshaft connecting rod journal.
Is the crankshaft connecting rod journal worn?
-
Go to Crankshaft Replacement Procedure
Go to Step 3
3
Check the oil pump pressure.
Is the oil pump pressure low?
-
Go to Step 4
4
Inspect the crankshaft connecting rod journals.
Are the journals out-of-round?
-
Go to Crankshaft Replacement Procedure
Go to Step 5
5
Inspect the connecting rods.
Is there a misaligned connecting rod?
-
Go to Pistons and Rods Replacement Procedure
Go to Step 6
6
Inspect the connecting rod bolts.
Are the connecting rod bolts torqued properly?
-
System OK
Go to Pistons and Rods Replacement Procedure

Piston Noises

Step Action Value(s) Yes No
1
Are any of the following noises heard: a sharp double knock when the engine is idling, a light ticking with no load on the engine, or a "slapping" noise when the engine is cold?
-
Go to Step 2
System OK
2
Inspect the piston pin and the bushing.
Is the piston pin or the bushing worn or loose?
-
Go to Pistons and Rods Replacement Procedure
Go to Step 3
3
Inspect the piston.
Is the piston broken or cracked?
-
Go to Pistons and Rods Replacement Procedure
Go to Step 4
4
Inspect the connecting rods.
Is there a misaligned connecting rod?
-
Go to Pistons and Rods Replacement Procedure
Go to Step 5
5
Inspect the piston position.
Is the piston 180° out of position?
-
Go to Pistons and Rods Replacement Procedure
System OK

Valve Mechanism or Valve Train Noises

Step Action Value(s) Yes No
1
Is a light tapping sound heard from the engine?
-
Go to Step 2
System OK
2
Inspect the valve springs.
Are the springs weak or broken?
-
Go to Cylinder Head and Valve Train Components Replacement Procedure
Go to Step 3
3
Inspect the valves.
Are the valves sticking or warped?
-
Go to Cylinder Head and Valve Train Components Replacement Procedure
Go to Step 4
4
Inspect the valve lifters.
Are the valve lifters dirty, stuck or worn?
-
Go to Cylinder Head and Valve Train Components Replacement Procedure
Go to Step 5
5
Inspect the camshaft lobes.
Are the camshaft lobes damaged or improperly machined?
-
Go to Camshaft Replacement Procedure
Go to Step 6
6
Check the oil supply to the valve train.
Is the oil supply insufficient or poor?
-
Go to Cylinder Head and Valve Train Components Replacement Procedure
Go to Step 7
7
Inspect the valve guides.
Are the valve guides worn?
-
Go to Cylinder Head and Valve Train Components Replacement Procedure
Go to Step 8
8
Inspect the valve spring seat.
Is the valve spring seat incorrect?
-
Go to Cylinder Head and Valve Train Components Replacement Procedure
System OK

GENERAL INFORMATION

Cleanliness and Care

An automobile engine is a combination of many machined, honed, polished and lapped surfaces with tolerances that are measured in the 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 on initial operation. Proper cleaning and protection of machined surfaces and friction areas is part of the repair procedure. This is considered standard shop practice even if not specifically stated.
Whenever valve train components are removed for service, they should be kept in order. They should be installed in the same locations, and with the same mating surfaces, as when they were removed.
Battery cables should be disconnected before any major work is performed on the engine. Failure to disconnect cables may result in damage to wire harness or other electrical parts.

On-Engine Service

Caution : Disconnect the negative battery cable before removing or installing any electrical unit, or when a tool or equipment could easily come in contact with exposed electrical terminals. Disconnecting this cable will help prevent personal injury and damage to the vehicle. The ignition must also be in LOCK unless otherwise noted.

Notice : Any time the air cleaner is removed, the intake opening should be covered. This will protect against accidental entrance of foreign material, which could follow the intake passage into the cylinder and cause extensive damage when the engine is started.



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