The aim of the study was to determine the effect of pouring temperature and pattern thickness onthefluidity, microstructure, andporosity of thecasting products. The casting method used is the evaporativecasting method. Thematerialused isAl-13.8% Si alloy (recycled) from the piston material of theL300 car. The furnace used is a type of crusibel furnace. Al alloys are melted in the furnace until they melt. Then pour it into the mold with atemperature variation of 650?C, 675?C, 700?C, 725?C, and 750?C Thetestresultsshowthat: (1) The higher the pouring temperature and the thickness of the pattern, the fluidity tends to increase . (2) The higher pouring temperature of Si phase dendrite is from small grains to long and thick debris. (3) The higher the pour temperature and thickness of the pattern, the percentage of porosity tends to decreas.