Hi guys just got my 2nd wrx this time its a 53 plate blobeye love it. Just one issue that i didnt notice on the test drive. where does the temp gauge go to once car is full heated up? mine hovers about quarter only then drops once you hit motorway. Also there is no heat coming from heaters. i have tried bleeding system past 2 days. Best result was today. Took hose that goes from header tank to top of radiator off at tank end and cap off at header tank. Turned engine on and started topping up header tank and flexing top radiator hose. Heater got warm kinda. Best result was when revs were at about 2500-3000rpm the heater went boiling and water starTed bubbling...well pouring out header tank plugged it all back up put 2 litres of water back in then heater went colder until it was cold. What am I doing wrong?

Thanks guys