Abstract: Fire investigation of vehicle fires caused by engine wading, including passenger car fire and special car fire are introduced. It is analyzed that, the direct fire cause is engine block damage, and the leaked oil is burnt, while the basic reason is intake cylinder after engine water intake, and high temperature vaporized water accumulated in the top space of piston causing bending and fracture of connecting rod, and breaking the cylinder block. Based on the analysis, the characteristics and investigation methods of wading vehicle fires are summarized. 

Key words: automobile fire, cylinder block damage; connecting rod bent； fire investigation