2014 130 GTI is losing antifreeze.....no noticeable leaks......no white smoke from exhaust.....black particles under cap of antifreeze bottle cap.....no oil n the base....any suggestions?
pressurize the system hot and cold. run in water at high speed/rpm with water bottle on the overflow coolant tube. how much coolant is it losing? head gasket is first suspect but may only leak at high rpms.