This situation can generally be determined by analyzing the chemical composition and hardness test of the connecting rod material, metallographic structure test, scanning electron microscope fracture analysis and other forces.

The possible reason is that the quenching microcracks lead to low-stress fatigue fracture, and there is pearlite in the organization.

Flake, oversized non-metallic inclusions, blocky ferrite, etc., lead to a decrease in the mechanical properties and fatigue life of the connecting rod.

Improper maintenance operation leads to bending or breaking of the connecting rod. For example, when cleaning carbon deposits by the soaking method, the cleaning fluid is not cleaned up.

Causes the Bare Engine to top the cylinder when restarting; for MG Roewe Maxus Engine equipped with a variable intake duct system, if the cleaning agent flow is not properly matched with the speed of the Bare Engine.

It may cause excessive accumulation of cleaning agent in the intake manifold, and the intake port becomes a short intake port when driving at high speed. The cleaning agent in the intake manifold is instantly sucked into the combustion chamber, causing the top cylinder.