bleeding the system can be tricky and can take a couple of attempts to ensure you have got rid of any airblocks. Also defo worth checking the rad fans as they do fail. Mishmoto do a excellent replacement and cheaper than OEM. Traders here do supply
always run with the aircon on. It helps prevent the rubber hoses from cracking.
You could have dicky connection. Have you changed the headunit or ever pulled that part of the dash out