Noticed the radiator overflow container was empty… refilled with additional coolant… a few days later, noticed coolant in container was very low… I took it to a local repair garage, they inspected the water pump and discovered it had a broken impeller. I replaced it with a new pump… Audi refused to honor new car warranty because repair was not completed by an Audi dealer. Seven months later a class action suit acknowledged the problem and included repairs by non Audi dealers… I'm still awaiting reimbursement of repair costs…