Valve leakage is a common engine fault, its failure is: insufficient engine power, difficult to start, exhaust smoke, crankshaft rocking resistance reduction. At the intake and exhaust pipe, you can hear the sound of "leaking". In the exhaust muffler part, if the sound of "choking" is heard, it means that the engine exhaust valve has air leakage; and in the intake side, the sound of "hissing" indicates that the intake valve has air leakage.(All those can be inspected by automotive videoscope.)

Cause analysis of valve leakage

1. valve and valve seat work inclined surface wear, ablation, produce spots or sunken, carbon deposit.

2. The gap between the valve stem and the valve duct is too large, the valve stem sways or bends, the valve head is askew, resulting in valve closure is not strict.

3. Weakening and losing elasticity of valve spring or breaking of valve spring can also cause the valve and valve seat can not be tightly matched.

4. Small valve clearance, valve rod heated expansion, tappet and rocker arm to open the valve, so that the valve can not be completely closed and leakage.

Resolution

The internal defects of the valve can be detected without disassembly by using Coantec automotive videoscope,which can avoid damage caused by demolition. At the same time, with Coantec automotive videoscope,we can take photos and videos of defects at any time, so as to facilitate subsequent failure analysis.