hey i have a s4 convertible.bought it about 3 months ago..i was wondering how often do you add coolant to car because i would have to add mine up to the full line in the reservoir tank about once each gas tank. the coolant level goes down really quick.sometimes the reservoir tank is empty when i check --> shouldnt the add coolant level buzzard come on? does anyone kno what could be? or is this somewhat normal.? the car has a new radiator. and i dont see any leaks.
thanks for any help..ive search and couldnt find an answer.

 

You should not have to add coolant. If you are there is a leak in the system somewhere, or the dreaded coolant seal leak inside the engine.

Start with the basics. Look everywhere for leaks and check your radiator cap. If the engine is not overheating and the coolant buzzer isn't coming on when the coolant is low, check the to see if the sensor is even plugged in or working.