Otherwise 306 made in 2000 won’t serve you long enough. In 1993 the company produced vehicles with 1.4 engine having code of KFW(TU3JP). Only exact type of antifreeze will suit Peugeot 306 cooling system. Only Red antifreeze type is suitable and you’ll need 6.5 liters of it. Make sure you service system at Peugeot with installed 1.4 engine correctly.
It will be advantageous to follow Peugeot’s rules for 2000 306 service. It’s obvious that every NFZ(TU5JP) motor needs good service as stated by Peugeot in instruction. If you choose other than Red coolant or use less than 7.8 liters, you can’t expect normal work. Produced in 1994 the 1.4 engine in 306 model will serve longer by this.