blondeaozichick: ok, I will try that ... thanks bourbsy ( and I assume that when you mean bleed the coolant its the same as bleeding the brakes and getting all fluid out then refilling) if not.. I don't know what you mean by bleeding the coolant
can I do the bleeding or do I need to get a mechanic to do it cos it needs a special tool or equipment?
It means bleeding the air out, not draining and replacing all the fluid. It is similar to the brakes in that there is a bleed nipple to get the air out. You'll need to have a good hose between the radiator and the expansion tank before you bleed it.
The bleed nipple can be a bit hard to get open if it hasn't been opened in a few years. You might be better off getting someone to bleed it for you. Take it to a holden dealer and get them to do it... they'll probably only charge you a few bucks.