2020 Audi A6 S Line 40 TDI Quattro S-A 2.0L Diesel · GF20 UJY

The 2.0-litre 40 TDI diesel is one of the more frugal powertrains in the A6 range, with manufacturer figures in the high 40s to low 50s mpg range, and real-world motorway driving typically returning mid-40s mpg. Diesel A6 saloons sit in a reasonable VED band for their registration year, and as a Euro 6 DG compliant vehicle it remains free from inner-city emissions charges that affect older diesels. Insurance for an S Line A6 Quattro is on the higher side — expect to be in groups 30-35 depending on the insurer and your profile — so obtain a quote before viewing.

Routine servicing through Audi main dealers is premium-priced, but independent specialists familiar with the VW Group platform typically charge 30-40% less while using the same parts. Front brake discs and pads are common consumables and cost more on Quattro variants than on front-drive cars due to the larger calipers. Expect an annual outlay covering fuel, tax, insurance and maintenance in the region of £1,400-£1,800 for a typical private owner, with diesel mileage bringing fuel costs down but tyres and brakes adding to the variable side. A timing belt service on the 2.0 TDI is generally not required as it uses a chain, but the DSG gearbox oil and filter change is the single biggest scheduled item to budget for.

The most pressing inspection point is the current odometer reading, since the sole MOT record shows zero miles and provides no real condition signal. With a 2020 car now six years old, expect somewhere in the region of 35,000-50,000 miles for a private vehicle or higher for an ex-fleet example, and verify this matches the Audi service history. Inspect the alloy wheels carefully for kerb damage — S Line trim runs larger wheels that are costly to refurbish — and check tyre brand, age (DOT date code on sidewall), and evenness of wear across each axle. Uneven wear can indicate tracking or suspension issues common to sport-suspended S Line models.

For the 2.0 TDI engine, look for any signs of oil leaks around the cam chain area and check the condition of the oil on the dipstick — black, gritty oil suggests missed services. On a cold start, listen for any rattle from the timing chain area, which can indicate stretched chains and is a known concern on higher-mileage examples. Check the Diesel Particulate Filter (DPF) — if the car is being used mainly for short trips, the filter may be filling without adequate regeneration, leading to expensive replacement. Finally, on the S-tronic gearbox, ensure it selects smoothly between P, R, N and D, and that there is no shudder on low-speed manoeuvres, which is an early warning of mechatronic or clutch wear on these gearboxes.