I think oil will be less soluble in water in high temperature. Oil is not soluble in water because it is not favoured by entropy change, so we cannot make oil soluble just by changing temperature. Rather increasing temperature would remove energy barrier and decrease solublity. [Energy barrier: Lets talk about small portion oil that is in the solution. These oil molecules will be sorrounded by many well ordered water molecules (of high potential energy). This energy is somewhat analogous to surface energy. Any two oil molecule cannot easily access each other because they are covered by sheat of water molecules. It required energy for removing this water molecules .... only after then there can be any interaction between two oil molecule. When we provide energy this energy barrier is overcome and oil molecules coalesce.] What do you think?