seems like you're having a bit of fun then hehe
when does it start overheating.... hills... traffic... highway.. which?
does your heater blow hot air?
how fast does the temp go up...
why other than the gauge do you think its overheating... is it bubbling and spewing out water or what?
when you lift the hood... can you smell anything abnormal?
does it feel hot.. when you lift the hood does alot of hot air ram at you?
and you still got the waterfall? drive your car to the nearest steep hill so the radiator is at the highest point... make sure the engine is still cool... turn off... take off radiator cap... start the car... keep topping up the radiator while it's running (with the heater on full blat) and keep doing this till you don't see any bubbles come out... put the cap on and see how she goes
what colour is the oil on your oil cap?
pull out your dipstick... is it normal coloured oil?
lemme know how you get on