I hate to be boring, but getting back to the topic -
quote: "And once iv driven it and come to a stop it's boiled the coolant,
As the overflow filler is wobbling and has steam coming out of it,
Not excessive amounts, but steam none the less. "
- the coolant normally operates above the boiling point of water, but the coolant is not just water, and it is pressurized, so it has a higher boiling-point in those circumstances.
- some flex in the filler is no surprize. If you think it is excessive, you might ask other VE drivers if you can inspect theirs, by way of comparison;
&/or, have a look around the reservoir and see if all of the screws etc are in place and fastened.
- I've never seen steam coming out of mine, and that doesn't sound correct.
The overflow holds some coolant when cold, and receives more as the motor warms up, but the overflow has no other source of heat, and although it gets warmer as you go along, it ought not approach the operating temperature of the motor. Steam makes me wonder if you have insufficient coolant in the overflow to condense the coolant flowing out of the radiator ?
I would suggest that you consider the following points -
are you using the correct coolant ?
is the cooling system, including the overflow reservoir, filled to the correct level (as per the dipstick in the overflow) ?
do you have the correct radiator cap, and is it functioning correctly* ?
* can be difficult to determine from a visual inspection alone. Sometimes the answer is to put in a new one, and see if it makes a difference.
In three years of owning a VZ 3.6L, I had to replace the radiator cap twice. I bought them from the Holden dealer for about $25.
I can't comment on aftermarket alternatives, because I have no experience of them.
In three years of owning a VE 3.0L, I have not had to replace the radiator cap at all (165,000 on the odo).
Please let us know how you get on.