Audi A6

All V6 engines in the A6 C6, including the 2.8 FSI BYT, sooner or later develop timing chain problems. Neglected maintenance and short-trip driving accelerate wear significantly.

Symptoms: Rattling on cold start that eases when warm; in advanced cases audible also during driving

The Multitronic CVT gearbox is considered a weak point of the A6 C6. Poor response to driver inputs, juddering, and premature transmission failure are common, especially without regular oil changes.

Symptoms: Juddering, shift point issues, delayed gear changes, in worst case breakdown

FSI engines are known for HP pump failures, particularly from 100,000–150,000 km. Failure causes starting problems and severe power loss. Repair is expensive.

Symptoms: Engine starts poorly or not at all, severe power loss, engine warning light

The V6 engine is under heavy thermal load. The thermostat and water pump wear earlier than on smaller engines. Failure can lead to overheating and engine damage.

Symptoms: Temperature gauge rises quickly or too high, coolant loss, poor heater output

The continuously variable Multitronic gearbox (01J/0AW) is considered the most serious weakness. Judder, rev fluctuations and complete failure. Early build years up to 2007 are particularly badly affected.

Blocked drain channels under the battery and sunroof allow water to enter the cabin. The comfort control module in the driver's footwell is damaged, leading to MMI total failure.

The Multitronic CVT tends to judder when pulling away, rpm fluctuations at partial load and, in the worst case, complete failure. All front-wheel-drive models are affected.

The high vehicle weight (up to two tonnes) accelerates wear of control arms, joints and anti-roll bar bushes. From around 150,000 km, extensive suspension work is virtually unavoidable.

Older A6 C6 examples show corrosion starting at the sills, door sill lower edges and tailgate. Where paint is damaged in the underbody area, corrosion progresses rapidly.

The cast-aluminium front control arms are prone to rubber bush wear. The long steel bolts in the wheel carrier corrode particularly badly and become extremely difficult to remove.

Pre-facelift vehicles (up to 2001) in particular show rust at the front wheel arches, door sill lower edges, and on the Avant at the roof edge above the windscreen.

Blocked drain holes under the battery lead to water ingress into the interior and can damage control units. Leaking cabin air filter housing seals exacerbate the problem.

The shaft seal between gearbox and propshaft on the A6 C5 eventually loses its seal. Gearbox oil drips onto the catalytic converter and burns off there. Often only diagnosed by smell or visual inspection from underneath.