Dynamic development of internal combustion engines creates a need to adopt a strategy concerning operational use of these driving units based on the knowledge of their technical condition. The assessment of technical condition belongs to tasks of technical diagnostics. This article presents an analysis of issues concerning vibration diagnostics of automatic compensators of clearances in piston valves of combustion engine. Scientific experiments focused on delivering information necessary to create (and also to validate) diagnostic models enabling assessment of technical condition of those elements of combustion engine that are essential taking into account effectiveness and durability that were carried out and described here. On the basis of the worked out diagnostic model, the algorithm for assessment of the technical condition of automatic compensators of valve clearance was created. (C) 2015 Elsevier Ltd. All rights reserved.