Knock Diagnosis; Engine Knocks Cold And Continues For Two–Three Minutes And/Or Knock Increases With Engine Torque; Repairing The Leak - Daewoo Nubira Owner's Manual

1A – 4IGENERAL ENGINE INFORMATION
2. Operate the vehicle under normal operating condi-
tions 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 deter-
mined 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:
S
The fluid level/pressure is too high.
S
The crankcase ventilation system is malfunctioning.
S
The fasteners are tightened improperly or the
threads are dirty or damaged.
Definition for Knock
Engine knock refers to the various types of engine noise.
Heavy knock is usually very loud and the result of broken
or excessively worn internal engine components. Light
Engine Knocks Cold and Continues for Two–Three Minutes and/or
Step
1 Does the engine knock when it is cold and continue
for two to three minutes or does the knock increase
with torque?
2 Inspect the flywheel.
Is the flywheel contacting the splash shield?
3 Reposition the splash shield.
Is the repair complete?
4 Inspect the balancer and the drive pulleys.
Is either the balancer or the drive pulleys loose or
broken?
5 Tighten or replace the balancer or the drive pulleys.
Is the repair complete?
6 Inspect the piston–to–bore clearance.
Is the clearance more than the value specified?
7
1. Rebore the cylinder and hone to size.
2. Replace the piston.
Is the repair complete?*
8 Inspect the connecting rod.
Is the connecting rod bent?
9 Replace the connecting rod.
Is the repair complete?
* Cold engine piston knock usually disappears when the cylinder is grounded out. Cold engine piston knock, which disap-
pears in about 1.5 minutes, is considered acceptable.

KNOCK DIAGNOSIS

Knock Increases with Engine Torque
Action
S
The flanges or the sealing surface is warped.
S
There are scratches, burrs or other damage to the
sealing surface.
S
The gasket is damaged or worn.
S
There is cracking or porosity of the component.
S
An improper seal was used, (where applicable).
Seals:
S
The fluid level/pressure is too high.
S
The crankcase ventilation system is malfunctioning.
S
The seal bore is damaged (scratched, burred or
nicked).
S
The seal is damaged or worn.
S
Improper installation is evident.
S
There are cracks in the component.
S
The shaft surface is scratched, nicked or damaged.
S
A loose or worn bearing is causing excess seal
wear.
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.
Value(s)
Go to Step 2
Go to Step 3
Go to Step 1
Go to Step 5
Go to Step 1
0.030 mm Go to Step 7
(0.001 in.)
Go to Step 1
Go to Step 9
Go to Step 1
Yes No
System OK
Go to Step 4
Go to Step 6
Go to Step 8
System OK
DAEWOO V–121 BL4