Heater / Cooling System..

[Capt Baldman]

My 1990 VN's heater is crap....takes forever to get hot, is that a common problem with this series..? (1) i think.
A Holden dealer refitted the thermostat, as it was missing, and it worked alot better for a while, until.....it over heated one day...( Cap not on properly)....now it's making all sorts of gugling or bubbling noise's.....is that because the Cooling system needs to be bleed.?
How do you do that....?

Thanks