Actually its a Leone (Australian name)
Here is the deal.
A few months back my cooling fluid has started to collect in the expansion bottle, overflowing it after some driving, even with the cap on.
After checking for coolant leaks, and finding none, I am scratching my head. It seems that AIR is somehow getting into the cooling system, thus displacing the fluid into the expansion bottle.
The system is under pressure OK, as when I open it hot, fluid shoots out, and when I open it cold air gets sucked in/out.
Fluid is definitely running out through the expansion bottle (I think), as I have to keep topping it up.
Here is the clincher: this seems to happen mostly after prolonged driving at over 80 km/h (I think).
The water burbles in the expansion tank when I turn the engine off. Dont know whether this is air or coolant.
Also, I dont think its the head gasket as there is no coolant in the oil and no oil in the coolant.
Sorry about the long post, but I am getting desparate.
Help?