I have a Toyota Yaris 2006 1.3. The air con was working 100% until i replaced the head gasket. After that the air con only works while my car is idling. If i slightly rev the car it cuts out. Took it in to check the coolant level and everything seems to be fine. There is however a strange noise coming from the compressor after i revved the car and when it stops the cold air comes back. Any help will much be appreciated.