Durability is the most important factor in the design of heat-exchangers to meet the specifications of the customers. To predict the durability, endurance tests are carried out. In this thesis, one of the endurance tests, thermal cycling is performed for three different internal coolant flows until failure which is known as Wöhler test. A tool is developed in MATLAB that could import data from all kinds of endurance tests and visualizes time histories of every channel of the test (test parameters such as temperature, pressure, flow). An algorithm is developed for Level Crossing counting method which works based on the Markov cycle counting method. This produces Level crossing curves (LCC) for all the channels of the test which says how well a test has been performed and the total number of cycles of the test. It was observed that the LCCs obtained from the tool gives accurate results when compared with those obtained from LMS software whose approach of producing LCCs is Rainflow cycle counting method. Strain measurements are performed for the same flowrates as that of the Wöhler tests. The results from strain measurements and Wöhler tests are used in the determination of Basquin’s coefficient of the Wöhler curve. It was observed that the optimal value of Basquin’s coefficient is 3.4.