Gas Turbine Lubrication Oil and its Cooling System

can someone explain how the cooling process of a gas turbine lubricating system works in relation to the fin fan cooler and the 3 way thermal valves.taking frame 5 as case study.

Is it that the oil is pumped to the system for lubrication and in the process ,the oil build up temperature and so it goes directly to the fin fan cooler(heat exchanger),temperature is reduced and then returns back to the sump and this cycle continues.or the oil get circulated round the system and return to the sump and this cycle continues until there is temperature build up and so the 3 way thermal valve is actuated and so the oil goes to the fin fan cooler for cooling