In this paper, the steady high speed oil flow in the spool valve and the local temperature distributions around the notches are simulated using a finite volume based CFD code. The temperature increase is due to the viscous heating effect, which is generally significant in highly-viscous fluid flow. Moreover, the deformation of the spool is simulated by the code ABAQUS (a finite element based software). These two codes are simply coupled on the spool surface, where the temperature distributions obtained from the CFD results are imposed as the boundary conditions of the deformation calculations. It is noted that this fluid-structure interaction (FSI) is modeled based on a loosely-coupled strategy, where the ABAQUS is started when the flow converges to a steady state and a stable thermal distribution has been reached. The aim of this study is to evaluate two different valve spools of the damage from jamming. Results have presented qualitative exhibitions of the temperature contours, appearances of the deformed spools, as well as the quantitative measurements of the radial deformations. Such evaluation provides the engineers a good assistant for design. Especially when the real case experiments are difficult to implement, the computer-based simulations are even powerful. (c) 2008 Elsevier Ltd. All rights reserved.