I'll be changing my coolant soon any tips would be appreciated. Do i ned to open the bleed bolts on the heads or will the air expel through the filler if the cap is left off?
No need to bleed - just fill slowly and run the engine for a bit with the cap off.
Check the tank carefully for cracks. It's more than likely you'll need a new tank and there's a little clip that requires a special tool to release and install (you could always hack it off and put a jubilee clip on).