69 

 

No. 039 Camshaft with abnormal sound   

Malfunction Causes 

Solution 

Engine with high water temperature 

Eliminate malfunction based on high water temperature;   

Engine oil with poor quality 

Replace engine oil;   

Oil filter blocked   Replace 

filter; 

 

Camshaft cam is worn, causing 
abnormal sound 

Check camshaft; repair or replace;   

Fit clearance between camshaft and 
camshaft bearing too large   

Check fit clearance; if necessary, repair engine or replace 
concerned malfunction parts;   

Camshaft seat burnt and damaged 

Check it is burnt and damaged; repair the engine;   

Hardness of internal spring of the 
gear not enough   

Replace the spring or assembly;   

When the engine is 
normal, sound similar 
as resonance 
appears; when 
severe, irregular noise 
appears.  

Pressure of oil pump abnormal   

Check oil pressure, which will cause abnormal sound if abnormal; 
if necessary, replace oil pump;   

 

 

Fit clearance between camshaft and wall 

Hardness of internal spring of the 
gear not enough 

Pressure of oil pump abnormal 

Camshaft seat burnt and damaged 

Engine oil with poor quality 

Oil filter blocked 

Engine with high water temperature

Camshaft with abnormal sound 

Repair

Repair 

Repair 

Replace 

Replace

 

Replace

 

Replace

 

Cam worn 

Replace

Normal 

Normal 

Normal 

Normal 

Normal 

Normal 

Normal 

Worn 

Not good

blocked 

Burnt 

Abnormal 

Stiffness 

Too large 

Abnormal 

 
 

 

 

70 

 
No. 040 Camshaft driving gear with abnormal sound   

Malfunction Causes 

Solution 

Lubricating oil with poor quality   

Replace lubricating oil   

Fit clearance not matched   

Strained clearance of driving gear not matched, causing 
abnormal sound; 

Improper assembling   

Check driving gear of admission camshaft and that of exhaust 
camshaft are correctly assembled; if not, reassemble;     

Matching angle under stress not even   

Adjust angle of driving gear; if necessary, replace it;   

Hardness of internal spring of the gear not 
enough 

Replace the spring or assembly; 

Check inlet filter screen of oil pump is blocked; if so, clean or 
replace;  

Check clearance between drive gear and driven gear of oil 
pump. And check relief valve is blocked; if so, repair or replace; 

Engine oil pressure too low 

Check lubricating system is leaking, and mainly check clearance 
of connecting rod tile; if leaking, eliminate it;   

Camshaft driving 
gear with 
abnormal sound 

Driving gear worn   

check driving gear is with obvious metal damaging traces, 
causing noises; if so, replace it;   

 

Reassemble 

Camshfat driving gear with abnormal sound 

Improper 
assembling 

Lubricating oil with poor 
quality 

Matching angle under stress not even 

Fit clearance of gears not 
matching

Hardness of internal spring of the gear not 
enough 

Engine oil pressure too 
low 

Driving gear worn 

Replace 

Repair 

Replace 

Repair 

Replace 

Replace

Normal 

Worn 

Normal 

Normal 

Normal 

Normal 

Normal 

Too low

Stiffness 
insufficient 

Not matching

Unusual

Poor

Improper

 
 

 

 

71 

 
No. 041 Cylinder knocking sound   

Malfunction Causes 

Solution 

Put screwdriver at filler port, and put your ear against the 
screwdriver lever, and carefully observe and listen;   

Flame out for cylinders gradually; if sound of this cylinder weakens 
or disappears, then it is confirmed that this cylinder has abnormal 
sound;  

To differentiate from other abnormal sound, fill in some lubricating 
oil at spark plug hole of this cylinder; if the sound weakens or 
disappears, then it is confirmed as piston knocking sound;   

Piston and cylinder wall severely 
worn, with too large clearance 

When knocking sound is very severe and filler port is smoking 
externally, it is because that clearance between piston and cylinder 
wall is too large;   

Fuel grade too low, with poor 
quality 

Check fuel quality, and confirm its grade; if not reaching specified 
requirements, replace it;   

Ignition time too early 

Check ignition timing. When the engine is at idling speed, ignition 
advance angle is 10°--12°; if not correct, adjust advance angle of 
initial ignition of the engine. When accelerating, ignition advance 
angle could automatically be increased to 20°--30°. If unusual, 
check ignition control system or replace ECU; 

Engine oil filter blocked 

Replace engine oil filter;   

Knock sensor malfunction   

Check knock sensor; if piston knocking is caused due to damaged 
knock sensor, replace it;   

Carbon deposit within the 
cylinder too many   

Check carbon deposit within the cylinder; if too many causing 
glowing ignition and piston knocking, clean it;   

Clearance of connecting rod tile 
too large 

Check and repair the engine;   

Piston ring blocked   

Check operations of piston ring; if blocked, repair or replace it;   

Compression ratio too large   

Check cylinder cover is grinding; if grinding too large causing 
combustion chamber smaller, and compression ratio too large 
causing piston knocking, replace cylinder cover;   

When the engine 
operates at idling speed, 
upper of cylinder body 
generates clear and 
rhythmical metal 
knocking sound “Dang”. 
When cooling, the sound 
becomes obvious. With 
rising engine 
temperature and speed, 
the sound becomes 
smaller or disappears. 

Clearance of piston ring too 
large  

Check piston ring; if necessary, replace it;   

 

 
 

 

 

72 

 

Fuel grade too low, with poor quality 

Ignition time too early 

Clearance of connecting rod tile 
too large 

Piston ring blocked 

Filter element blocked 

Clearance of piston too large 

Carbon deposit within the cylinder 
too many 

Knock sensor malfunction 

Piston and cylinder wall severely worn its 
clearance 

Cylinder knocking 
sound 

Repair 

Repair 

Repair 

Replace 

Replace 

Adjust 

Replace 

Replace 

Replace 

Normal 

Too large

Normal 

Normal 

Normal 

Normal 

Normal 

Normal 

Normal 

Blocked

Blocked

Large clearance 

Too many

Abnormal

Too early

Poor quality

Worn