To the top of the document
Kalos/Aveo
To Previous PageTo Next Page
GMDE Start PageLoad static TOCLoad dynamic TOCHelp?

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. Lowcompression pressure may be the fault of the valves orthe pistons. The following conditions should be consideredwhen 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 sparkplug port.
  4. Insert the engine compression gauge into each sparkplug port.
  5. Crank test each cylinder with four to five compressionstrokes using the starter motor.
  6. Crank test each cylinder with four to five compressionstrokes using the starter motor.
  7. The lowest reading should not be less than 70% ofthe highest reading. The compression gauge readingshould not be less than 689 kPa (100 psi) for any ofthe cylinders.
  8. The lowest reading should not be less than 70% ofthe highest reading. The compression gauge readingshould not be less than 689 kPa (100 psi) for any ofthe cylinders.
  9. Examine the gauge readings obtained after the four"puffs" per cylinder are obtained from cranking thestarter motor. The readings are explained in the followingdescriptions:
  10. Examine the gauge readings obtained after the four"puffs" per cylinder are obtained from cranking thestarter motor. The readings are explained in the followingdescriptions:

Oil Pressure Test

StepActionValue(s)YesNo
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 1.2S : 0.040mm (0.00157 in.) 1.4D : 0.042 mm (0.00165 in.)
Connecting 1.2S : 0.040 mm (0.00157 in.) 1.4D : 0.070 mm (0.00275 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 byvisually finding the leak and replacing or repairing thenecessary parts. On some occasions, a fluid leak maybe difficult to locate or repair. The following proceduresmay 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 operatingtemperature, park the vehicle over a largesheet of paper.
    2. Wait a few minutes.
    3. Find the approximate location of the leak bythe drippings on the paper.
  3. Visually check around the suspected component.Check around all the gasket mating surfaces forleaks. A mirror is useful for finding leaks in areas thatare hard to reach.
  4. If the leak still cannot be found, it may be necessary toclean the suspected area with a degreaser, steam, orspray solvent.
    1. Thoroughly clean the area.
    2. Dry the area.
    3. Operate the vehicle for several miles at normaloperating temperature and varying speeds.
    4. After operating the vehicle, visually check thesuspected component.
    5. If you still cannot locate the leak, try using thepowder 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 theleak 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 tothe manufacturer's directions when using the kit.
  1. Pour the specified amount of dye into the engine oil filltube.
  2. Operate the vehicle under normal operating conditionsas directed in the kit.
  3. Direct the light toward the suspected area. The dyedfluid will appear as a yellow path leading to thesource.

Repairing the Leak

Once the origin of the leak has been pinpointed andtraced back to its source, the cause of the leak must bedetermined in order for it to be repaired properly. If agasket is replaced, but the sealing flange is bent, thenew gasket will not repair the leak. The bent flange mustbe repaired also. Before attempting to repair a leak,check for the following conditions and correct them asthey 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 brokenor excessively worn internal engine components. Light knock is a noticeable noise, but not as loud. Light knockcan be caused by worn internal engine components.Loose or broken external engine components can alsocause heavy or light knock.

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

StepActionValue(s)YesNo
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?
1.2S : 0.045 mm (0.00177 in.) 1.4D : 0.040 mm (0.00157 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

StepActionValue(s)YesNo
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?
1.2S : 0.040 mm (0.00157 in.) 1.4D : 0.042 mm (0.00165 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?
1.2S : 0.040 mm (0.00157 in.) 1.4D : 0.070 mm (0.00275 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

StepActionValue(s)YesNo
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?
1.2S : 0.040 mm (0.00157 in.) 1.4D : 0.070 mm (0.00275 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

StepActionValue(s)YesNo
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?
1.2S : 0.31 mm (0.012 in.) 1.4D : 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?
12.S : 0.040 mm (0.00157 in.) 1.4D : 0.042 mm (0.00165 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 bleedlifter 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 fewminutes. This is a normal condition.

Knocks at Idle Hot

StepActionValue(s)YesNo
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?
1.2S : 0.025~0.045 mm (0.0010~0.0018 in.) 1.4D : 0.020~0.040 mm (0.0008 ~ 0.0016 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?
1.2S : 0.4~0.6 mm (0.016~0.024 in) Toward Thrust Side
1.4D : 0.7~0.9 mm (0.0276~0.0354 in.) Toward Thrust Side
Go to Step 19
System OK
19
Install the correct piston.
Is the repair complete?
-
Go to Step 1
-

Noise Diagnosis

Main Bearing Noise

StepActionValue(s)YesNo
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 specifiedvalue?
1.2S : 0.31 mm (0.012 in.) 1.4D : 0.1 mm (0.003 in.)
Go to Crankshaft Replacement Procedure
Go to Step 4
4
Inspect the crankshaft journals.
Are the crankshaft journals out-of-round?
1.2S : 0.005 mm (0.0002 in.) max. 1.4D : 0.004 mm (0.00016 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

StepActionValue(s)YesNo
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

StepActionValue(s)YesNo
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

StepActionValue(s)YesNo
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 tolerancesthat are measured in the ten-thousandths ofan inch. When any internal engine parts are serviced,care and cleanliness are important. A liberal coating ofengine oil should be applied to friction areas during assembly,to protect and lubricate the surfaces on initialoperation. Proper cleaning and protection of machinedsurfaces and friction areas is part of the repair procedure.This is considered standard shop practice even ifnot specifically stated.
Whenever valve train components are removed for service,they should be kept in order. They should beinstalled in the same locations, and with the same matingsurfaces, as when they were removed.
Battery cables should be disconnected before any majorwork is performed on the engine. Failure to disconnectcables may result in damage to wire harness or otherelectrical parts.

On-Engine Service

Caution : Disconnect the negative battery cable beforeremoving or installing any electrical unit, orwhen a tool or equipment could easily come in contactwith exposed electrical terminals. Disconnectingthis cable will help prevent personal injury anddamage to the vehicle. The ignition must also be inLOCK unless otherwise noted.

Notice : Any time the air cleaner is removed, the intakeopening should be covered. This will protect against accidentalentrance of foreign material, which could followthe intake passage into the cylinder and cause extensivedamage when the engine is started.



To Previous PageTo Next Page
© Copyright Chevrolet Europe. All rights reserved