In the present study a method for estimating local heat transfer distributions of internal cooling systems is described. Experimental data and finite element analysis are applied for this method. The investigations considered in this paper are based on experiments performed on a two-pass cooling channel connected by a 180 deg bend with internal rib arrangements. The solid walls of the cooling channels are made of a metallic material. During the experiment the temperature response of the outer surface induced by heated internal flow is recorded by infrared thermography. The internal heat transfer distribution is obtained using an optimization routine. For each loop of the optimization a transient thermal simulation of the solid body is performed applying the boundary and inlet conditions of the experiment. The temperature of the outer surface calculated by the finite element simulation is compared to the measured temperature recorded by infrared thermography. The difference of these temperature distributions is minimized by adapting the distribution of the internal heat transfer coefficients. The adaptation is conducted on single elements of the inner surface and will be presented in detail in the paper. This approach allows us to achieve a high resolution in heat transfer while minimizing the required iterations. The combination of experimental data and finite element analysis allows us to consider three-dimensional conduction effects in the solid and the streamwise fluid temperature development. Results are compared to literature data.