If you are adding a thermostat to a system , which has been running on tap water and direct fan etc , i would recommend you check rest of the cooling system too , maybe get a new radiator ,pour some coolant in or flush the system , last time i checked for my margalla , copper radiator was for 9.8k and almunium was i guess 7.8k from makka autos (nagan) also get your temp guage fixed or add another aftermarket one.