Chery QQ Service Manual 465 Engine Mechanical System
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Chery Automobile Co., Ltd
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Bearing clearance is too big.
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Crankshaft connecting rod journal wear
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The oil is too thin or/and oil filter is too dirty
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Oil pressure is too low
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The shaft journal of crankshaft connecting rod is out of round.
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Connecting rod malposition
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Connecting rod nut fixed torque is not correct
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Bearing shell is not correct or bearing shell is malposition
3 Piston noise
It is hard to distinguish the noise generated by piston pin or connecting rod, loose of piston
pin may result in sharp double knocking sound, usually, it can be heard when the engine is
idling or the engine speeds up suddenly then slow down; the piston pin will be ticking
slightly if the piston is installed not properly, the noise becomes more obvious if the engine
works without heavy load; too much clearance between piston and cylinder liner will result
in sound of knocking the cylinder from inside, this kind of noise is similar to metal knocking
sound, just like the piston slap the cylinder shell from inside during the process of stroke.
Engine noise slowing down after warming up is a sign for piston to slap cylinder, there is too
much clearance between piston and cylinder liner when the engine is cold, sound of slaping
is much louder.
The following circumstance can lead to piston noise:
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Piston pin wear or too loose
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Piston pin is installed not properly.
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There are too much clearance between piston and cylinder liner.
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Lubrication is not enough.
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The carbon deposit at piston crown knocks cylinder head.
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Piston ring groove wear or fracture
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Piston fracture
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Connecting rod malposition
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Piston ring wear or damage
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The clearance of piston ring groove is too big.
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The clearance of piston ring ends is not enough.
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Piston malposition is at a angle of 180 degree
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The shape of piston skirt is not correct.
4 Flywheel noise
Check whether or not the flywheel is loose or cracked according to the following steps:
4.1 Drive the vehicle at the speed of 32 km/h.
4.2 Turn off the engine
The flywheel may be loosened or damaged if you hear the kind of pinging sound, this kind
of pinging sound comes to maximum while decelerating. Bearing knocking sound can result
from looseness of bolts. It depends on stability of idling to generated how much slapping
sound when the engine is idling at high speed, the noise can be made or can not be made if
transmission drive put into gear. Check the connecting bolts between transmission and
flywheel, crankshaft and flywheel first, before make sure whether or not there is some