No, actually the Quran does not override the authentic Ahadeeth, because the Ahadeeth are the container of the sunnah, it is the sunnah reaches us today. The Ahadeeth are checked for authenticity by information provided by those who narrated the Ahadeeth themselves, and the information was passed down and we have it today. So every Hadith that is authenticated must be followed, in other words the Quran and authentic Hadith/sunnah come together.
Furthermore, the Quran is not meant to be an encyclopedia, and hence does not contain details on how to do things. Like Salat for example, about 90% of salat is not in the Quran. And hence, one will find rulings/orders in the Ahadeeth that isn't in the Quran, and it is an obligation on us to follow these orders/rulings from the Ahadeeth/Prophet. (We must follow His sunnah in regards to religion, in general).
وَمَا آتَاكُمُ الرَّسُولُ فَخُذُوهُ وَمَا نَهَاكُمْ عَنْهُ فَانْتَهُوا
وَاتَّقُوا اللَّهَ إِنَّ اللَّهَ شَدِيدُ الْعِقَابِ
And whatever the Messenger has given you - take; and what he has
forbidden you - refrain from. And fear Allah ; indeed, Allah is severe
Surat Al Hashar Ayah 7
And further more, the Quran and Authentic Sunnah do not and cannot contradict each other (as is clear in Ansari's answer). The Sunnah/Ahadeeth are also an explanation of the Quran, those who rely on the Quran, and their own (personal) understanding/interpretation only, are prone to deviation. An example, lets say that one wants to know what the ruling is for stealing, and the ruling is cutting the hand, but in Arabic Hand (يد) can mean from the finger tips to the wrist, or from the finger tips to the elbow, or it can mean the whole arm. And if the sunnah did not exist to clarify, there would be these three opinions which two of them are wrong.
So The Sunnah is an explanation/tafseer for the Quran, if you want to find a ruling you go to the Quran, but then you go to the Sunnah, and just like one cannot stop at the Quran, one cannot stop at the sunnah, and hence must go to how the Sahabah understood and implemented it. So the main point here in my answer is that the Quran and the Sunnah are two connected inseparable sources in Islam, in which rulings can be deduced (mind you, there are more than two, but I will just mention the Quran and the Sunnah here). I pray my answer is clear, and I apologize for it's lengthiness.
Sources: Islamic Online university Foundations of Islaamic Studies part 2