In this paper, due to the importance of the amount and distribution of the liner temperature in the performance of the internal combustion engine, the effect of the crosshead cylinder-drilling method on this parameter was experimentally investigated. For this purpose, the experimental tests were performed on a 3-cylinder engine with and without inter-cylinder holes. To measure the temperature of the liner, thermocouple sensors were installed in the areas of the bore bridges on the engine block and the areas between the combustion chambers on the engine cylinder head. Then the tests were carried out during a fixed and standard procedure in full load mode for two modes of with and without inter-cylinder holes in different working conditions including various water temperatures and engine speeds. The experimental results showed that this method can effectively and significantly reduce the temperatures of the critical areas of the bore bridges and areas between the combustion chambers. This amount of reduction for the bore bridges for the temperatures of 90, 100 and 110 degrees was on average equal to 32, 62 and 53 degrees of Celsius, respectively. For the areas between the combustion chambers for the temperatures of 90, 100 and 110 degrees, this amount of reduction reached 4, 8 and 8 degrees of Celsius respectively. The results indicate the desirable effectiveness of the cross-head cylinder-drilling method in the temperature of the critical areas between the cylinders, which can effectively be used in the development of new engines.