The aim of this paper is to show the complex thermal analyses used for examining cooling properties of a liquid cooling system integrated into an aircraft fuel metering pump. The cooling is provided by flow of aviation fuel-kerosene. The main advantage of this solution is easy implementation in the place of engine bay. Two methods of thermal analyses are used according to the level of cooling system development. Thermal network analysis is intended for first estimation of thermal conditions and cooling system properties. Numerical thermal analysis based on the finite-element method is used for examination of limit operating conditions which cannot be realized during laboratory testing. The experimental measurement by an infrared camera is used for result verification and identification of thermal properties in laboratory conditions. The goal is to maintain the temperature conditions of the control electronics within the temperature limits.