Daewoo NUBIRA - Connecting Rod Bearing Noise Symptom; Main Bearing Noise; Noise Diagnosis

1A – 8IGENERAL ENGINE INFORMATION
DAEWOO V–121 BL4
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 toOil Pres-
sure Test
Go to Step 3
3 Inspect the crankshaft end play.
Is there excessive crankshaft end play?
0.1 mm
(0.0039 in.)
Go toCrank-
shaft Replace-
ment Proce-
dure
Go to Step 4
4 Inspect the crankshaft journals.
Are the crankshaft journals out–of–round?
0.004 mm
(maximum)
(0.0006 in.)
Go toCrank-
shaft Replace-
ment Proce-
dure
Go to Step 5
5 Inspect the belt tension.
Is there excessive belt tension?
Go toTiming
Belt Replace-
ment Proce-
dure
Go to Step 6
6 Inspect the crankshaft pulley.
Is the crankshaft pulley loose?
Go toCrank-
shaft Replace-
ment Proce-
dure
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 toCrank-
shaft Replace-
ment Proce-
dure
Go to Step 3
3 Check the oil pump pressure.
Is the oil pump pressure low?
Go toOil Pres-
sure Test
Go to Step 4
4 Inspect the crankshaft connecting rod journals.
Are the journals out–of–round?
Go toCrank-
shaft Replace-
ment Proce-
dure
Go to Step 5
5 Inspect the connecting rods.
Is there a misaligned connecting rod?
Go toPistons
and Rods Re-
placement Pro-
cedure
Go to Step 6
6 Inspect the connecting rod bolts.
Are the connecting rod bolts torqued properly?
System OK Go toPistons
and Rods Re-
placement Pro-
cedure