Excessive oil consumption in a 2014 Audi A5, requiring weekly oil top-offs, indicates a significant internal issue, often accompanied by a rattling noise when the oil level gets too low. This problem can manifest under various operating conditions but is particularly noticeable during regular driving scenarios. The severity of the issue is high, as it not only necessitates frequent oil additions but also poses a risk of engine damage. Warning signs include the need to frequently add oil, a noticeable decrease in engine performance, and unusual noises from the engine compartment, which worsen when the oil level is not maintained.

The likely root cause of this issue is worn piston rings or valve seals, leading to oil leaking into the combustion chamber and burning off during operation. Another potential cause could be a problem with the PCV (Positive Crankcase Ventilation) system, which can cause excessive crankcase pressure and lead to oil being pushed past the piston rings into the combustion chamber. If not addressed, this issue can result in significant engine damage, including scored cylinders and damaged bearings, due to inadequate lubrication and excessive heat from the burning oil.