so changed my coolant and now after driving on the highway there is alot of foam i used suburu genuine coolant and conditioner, and also my coolant overflow tank over flowed for some reason it wasnt overly full or anything.

 

Did you change the coolant for any reason like a ruptured rubber hoses? If so, sometimes replacing the bust hose makes another leak due to increased pressure. As it leaks it also draws in air making the coolant aerated.

A worse scenario is a blown head gasket between the cylinder and coolant passage. This aerates the coolant as the piston pushes combustion gasses into the coolant. You'd also notice small amounts of water coming out of the exhaust as water leaks into the cylinder and is passed out the exhaust valve.

Have a look into the radiator as the engine is turned on and reved, and see if the coolant becomes more aerated as you rev it. Might be a good telltale. Good luck