An approach to cope with changing market needs is to design engineering systems that can be changed easily. However, in order to identify suitable candidates to be made more changeable, one has to be able to analyse the changeability of engineering systems. Hence, this paper introduces a dependency modelling technique that seeks to support companies in assessing the changeability of complex engineering systems. The research was carried out based on the design research methodology with a focus on method development. The primary result of this work is the provision of a design support that can be used to provide an estimation of system changeability by examining (1) the initiating points of change, (2) the direct propagation of change, (3) the indirect propagation of change, (4) the likelihood of change, and (5) the impact or effort of change. The technique developed uses a matrix-based approach and draws on the change prediction method to generate change indices for individual system components. By referring to the change indices generated, the changeability of engineering systems can be examined systematically. A heavy-duty diesel engine is used in this work as an example to demonstrate how the technique can be applied.