only owned my streetka for a few weeks and already we have the first problem. Was driving home tonight and steam was coming out from bonnet, seem that the hose from expansion tank to radiator has a split. How easy are these to replace? And what is the best way to add new coolant to the system. Thanks for any advice 

Hello and welcome to the "endless problem with my StreetKa " club :)

I recommend to get your car to the good garage and check it over. I had similar problem and ended up with lots of trouble (originally was a very simple fault, but experimenting with it made it far worst).

If pressure build up in the cooling system, good chance , you have a stuck thermostat (if the car was standing long and not used before you bought it , 99% ) or a faulty water pump. It is an easy and cheap fix. If you just replace the hose and carry on using the car, you can end up with exploding HCV , header tank or cook you head gasket. 

Well we think we've fixed one problem but now have another !it was actually the HCV that had exploded and two hoses had come away , New part has been fitted AND a new problem created ...we now only get hot air through to the inside of the car , anyone know what is causing this problem . Any help would be appreciated 

14 hours ago, Classiccharm said:

Well we think we've fixed one problem but now have another !it was actually the HCV that had exploded and two hoses had come away , New part has been fitted AND a new problem created ...we now only get hot air through to the inside of the car , anyone know what is causing this problem . Any help would be appreciated 

Oh , the good old HCV. For me it is a constant problem.

Where did you get the new HCV from? Cheap (£10-20) eBay or genuine Ford? If you get the cheap aftermarket, good chance it is broken already. When I replaced mine, the first one was working around 3 weeks while the second one for a few hours. 

Also check the control pane/heater switch as well. You will need a bulb and two wires or a multimeter :
 

Thats how you checking it with a bulb:

 

And if you choose the multimeter:

Let us know how it is going. 

Just dropped the car off to a friend who's a mechanic. He's in dubai fixing cars atm but back tomorrow so is going to look at it for me :)