The executive-class C7 A6 with the four-cylinder diesel — a car built around long-distance comfort, paired with an engine that rewards exactly that kind of driving.
The A6 is a larger, heavier car than the A4 it shares underpinnings with, which means the four-cylinder diesel works somewhat harder here — still comfortably within its limits on the motorway, but worth knowing if most of your driving is urban.
Later facelift examples (from around 2015) received the EA288 engine update covered on the linked engine page; earlier C7s used the preceding EA189 generation, which is worth asking about specifically given its different Dieselgate-era emissions history.
This is about the car itself — for engine-specific failure points, see the dedicated engine page below.
Facelift (post-2015) C7 A6 models share their 2.0 TDI with several other VW Group executive cars of the same era. Full detail on EGR/DPF behaviour lives on the dedicated engine page.
FULL ENGINE BREAKDOWNAudi 2.0 TDI (EA288) — Reliable or Not →Confirm which engine generation the specific car has — pre- or post-facelift — since this affects both emissions history and some of the known failure points.
If the car has air suspension, cycle it through its settings and check it holds height overnight rather than sagging.
Ask directly about driving pattern — as with other modern diesels, a mostly-urban history raises EGR/DPF risk meaningfully.