my tf exec sedan 3l 5 speed is pushing coolant out the overflow hose about the same time this started happening i lost the little steel ring of the inside of my radiator cap do you think this could be the problem any other ideas ?

Get yourself a new radiator cap.

It sounds like the water is escaping as it is trying to build up pressure, and is leaking into the hose.

This should fix your problem, and I suggest you don't drive it far in the meantime.

http://www.ebay.com.au/itm/Tridon-CC1390-Tridon-Recovery-Radiator-Cap-/252192134800?fits=Make%3AMitsubishi|Model%3AMagna&hash=item3ab7d29690:g:ug4AAOSwnH1WW~2Y

my tf exec sedan 3l 5 speed is pushing coolant out the overflow hose about the same time this started happening i lost the little steel ring of the inside of my radiator cap do you think this could be the problem any other ideas ?

It's not overheating. The radiator cap has a valve in it, as the engine warms up the valve is closed and coolant pressure builds up to the pressure marked on the cap, above that water is released into the bottle. When the car cools down, the valve opens and reservoir coolant is sucked back in.

This is Basic Mechanics 101.

Replace the cap. The current one is stuffed.