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Torque shop: Unmodified old car fails emission test
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Poor emissions can be caused by worn piston rings or other components not working as they should.
PHOTO: LIANHE ZAOBAO
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An overhaul is a time-consuming and expensive repair job which entails taking the engine apart and replacing major components.
The most common reason to do so is when the piston rings are worn. This condition leads to engine oil seeping into the combustion chamber. The burnt engine oil will be expelled together with the combusted fuel-air. However, this may not be the reason your car failed its inspection routine.
