overheat

so i bought a car the other day and literally on my way home it over heated (when i was test driving everything was fine) coolant was bubbling in the reservoir and spilled out the overflow, so topped up with water and drove home. did some tests rad cap and everything is good, took out thermostat and it opened in boiling water, still didnt put thermo back in. then drained the system and put water in for now to not waste money. and the double checked all the hoses for leaks and everythings good

when idling the temp goes up and stays in middle then took it for about an 10 min drive and the temp started going over the middle, pulled back home and the water in reservoir was bubbling, the top rad hose is really hot and bottom rad hose just slightly less hot. oil looks good not milky or anything, rad cap good, heater and ac works as should, no issues starting car, any ideas?

car is an skyline r34 with an rb20de neo engine and before yous ask it was private sale can't take it back