On mine it's between a third and a half.

On 26/02/2017 at 9:14 PM, frankieh said:

I guess I'm mostly wondering why the recent change..  other than replacing the plastic pipe I've changed nothing.     It's definately coming from the overflow as the puddle is directly under the outlet and all "car" between the overflow and the ground is coated in green coolant.   There doesn't appear to be any other leakage.  I made a point of checking at work where I park it and sure enough the only place with a puddle of coolant is the front drivers corner right under the overflow hose.  

 

I suppose it's possible that the radiator cap has lost pressure or seal and it's allowing it out under lower pressure, I have a spare here so I can try it.

I may get slammed for this on old post😂, did you find your solution? 

My 05 BA2 T M6 always sat just slightly above 1/4 and after the 160k coolant change at 33.3/40% it sits between 1/3 and 1/2 now. It's 16yo totally stock and still going hard but noticed on YouTube most T's sit below the 1/2 mark. Everyday I don't ring RACQ for a tow is a blessing 🤞