In this study, organic liquid Octamethylcyclotetrasiloxane (OMCTS) confined to molecularly thin layers is studied. It has been shown that when shear force is applied on a thin layer of OMCTS, the sliding is characterized by a stick-slip pattern. Surface force balance (SFB) experiments, supported by molecular dynamic simulations suggest that the stick-slip friction is a result of an abrupt phase transition between solid like and liquid like phases during sliding. This transition, in principle, should be expressed as the change in surface separation during shear because of density differences between the solid and liquid phase, which is expected to be in the order of 0.5 nm (for 5-6 molecular layers). In this study were looking for an experimental indication for this phase transition in OMCTS thin film during stick & slip friction, by video-recording the movement of the surfaces back and forth during the sliding (movement of an interference fringes) and looking for a movement correlated to the slip spikes. For the first time we showed experimentally that no indications were found for the expansion between the confined organic liquid during its stick-slip shear behavior (within our 1.3 Å experimental resolution). Our experimental results do not support the common phase transition model for Stick - Slip. Preliminary results show that we have succeeded to conduct a clean SFB experiment with pure OMCTS confined between the surfaces, and these enable us to examine the nature of the phase transition during the stick-to-slip event.