Here is a link with info on the engine design for reference.
https://toyota-club.net/files/faq/18-03-20_faq_df_r4_eng.htm#A25A-FKS
Cooling system
1 - water inlet with thermostat, 2 - water pump, 3 - throttle body, 4 - EGR valve, 5 - EGR cooler, 6 - water by-pass outlet, 7 - flow...