only just done the heater valve on my sisters 125ztec the valve is 35 quid new and take ten mins to change under bonet you will see a long rubber seal that can be removed at the back end of engine bay near windscreen remove it in the centre you will see 2 pipes coming out of a plastic fiting at the back you will see 2 more pipes and a little siver motor that is the heater valve remove the wireing plug all 4 pipes and replace the same as removal its quite simple and easy to do yourself