Audi A6 vs BMW 5 Series: which is the better used buy?

On DVSA MOT records the Audi A6 and the BMW 5 Series are too close to call — 0.3 percentage points apart on first-time MOT passes once you allow for the age of each fleet, which is inside what the choice of cars counted can move. A winner is named only at 2 points or more. A pass with rectification at the station counts as a pass here, and as a failure in DVSA's own initial-test measure. Choose on the fault patterns and running costs below.

MOT first-time pass rate

Counted from DVSA’s anonymised MOT test records. “vs age-matched” compares each model against what the national fleet scores at the same age — the only fair better-or-worse number, because an older fleet fails more whatever its build quality.

Audi A6

Pass rate83.1%

Age-matched national76.6%

Difference+6.5

Tests12,504

BMW 5 Series

Pass rate82.9%

Age-matched national76.7%

Difference+6.2

Tests20,829

Model	Pass rate	Age-matched national	Difference	Tests
Audi A6	83.1%	76.6%	+6.5	12,504
BMW 5 Series	82.9%	76.7%	+6.2	20,829

These figures count every generation still on the road, not only the one described below: mostly Audi A6s registered 2006–2022 and BMW 5 Series registered 2003–2022.

Source: DVSA MOT Anonymised Data 2025 (Open Government Licence v3.0). National first-time pass rate 77.3%. Class 4 tests in Great Britain, test type NT (a normal annual test), retests excluded. A pass, or a pass with rectification at the station, counts as a first-time pass; DVSA's own initial-test measure counts a rectified pass as a failure and so reports a lower figure. Testing in Northern Ireland is run separately by the DVA under its own rules. The difference is worked out before rounding, so it can be 0.1 away from the two rounded figures beside it.

Audi A6

C8, 2018–2024 · premium executive saloon

The C8 Audi A6 (2018–2024) is mechanically solid but suffers from MIB3 infotainment freezes pre-2022, DPF blockages on short-trip 2.0 TDI diesels, and owner-reported 48V mild-hybrid battery faults. The 2022 facelift fixed the infotainment. Best-buy years: 2022–2024. Worst: 2018.

What goes wrong

Safety recall R/2020/138recall
Moisture may enter the belt-driven starter-alternator
34,982 vehicles in the whole recall (DVSA’s figure for every model it covers) · built between 1 June 2017 and 31 March 2020
Large recall — 34,982 vehicles. Check a car by registration on GOV.UK.
Safety recall R/2020/265recall
Moisture may enter the belt driven starter-alternator
11,936 vehicles in the whole recall (DVSA’s figure for every model it covers) · built between 10 August 2018 and 11 March 2020
Large recall — 11,936 vehicles. Check a car by registration on GOV.UK.
MIB3 infotainment freezemoderate
Screen goes black or freezes on Apple CarPlay / Android Auto; reboot required
2018–2021 · Free under software update; £350–£800 if hardware MMI swap needed
Check: During test drive, connect phone via Apple CarPlay and use it for 15+ minutes. Try switching audio sources. Reproduce the freeze and have it noted on inspection.
DPF blockage (2.0 TDI on short trips)major
Limp mode warning; engine warning light; "DPF full" message
All TDI variants · Mileage-independent — driving pattern matters more · £450–£900 forced regeneration + drive cycle; £1,800+ if DPF replacement
Check: Avoid TDI variants that have only ever done short city trips. Ask about typical journey length. Look for forced-regen events in service history.

Typical asking price:: £12,990–£25,995, median £18,595 (middle 80% and median, cars on Autoza on 29 October 2026)
Fuel economy:: 42–49 mpg for 2.0 TDI; 28–33 mpg for 55 TFSI petrol
Vehicle tax:: £200/year standard rate from the second year, hybrids included — the alternative-fuel discount ended on 1 April 2025 (2026/27 rates). A car registered from April 2017 that listed at over £40,000 new (options included) also pays the £440/year Expensive Car Supplement in years 2–6 — it is the price when new that counts, not what you pay for it used.
Best years:: 2022, 2023
Years to avoid:: 2018

Used Audi A6s for sale Full A6 fault guide Used Audis

Also compare:

A6 vs E-Class

BMW 5 Series

G30, 2017–2024 · premium executive saloon

The G30 BMW 5 Series (2017–2024) is generally robust in UK conditions. Owners report timing-chain wear on pre-2018 B47 diesels above 75,000 miles, diesels built to mid-2018 are covered by DVSA EGR-cooler recalls, and Touring rear air suspension can wear after 95,000 miles. Best-buy years: 2019–2021. Worst: no single year stands out on DVSA MOT results.

What goes wrong

Safety recall R/2022/255recall
Undetected EGR System leaks may cause thermal activity in the intake manifold
322,745 vehicles in the whole recall (DVSA’s figure for every model it covers) · built between 8 March 2016 and 14 September 2020
Large recall — 322,745 vehicles. Check a car by registration on GOV.UK.
Safety recall R/2022/206recall
The exhaust gas recirculation cooler may leak over time and cause thermal incident
319,399 vehicles in the whole recall (DVSA’s figure for every model it covers) · built between 22 February 2017 and 15 May 2018
Large recall — 319,399 vehicles. Check a car by registration on GOV.UK.
Engine — B47 diesel timing chaincritical
Rattle on cold start that fades after 5–10 seconds; metallic chain noise when accelerating
Pre-2018 (B47 engine code, mostly 520d / 525d) · Above 75,000 miles · £2,500–£4,500 (chain, guides, tensioner, gaskets, labour)
Check: Cold-start in person — never accept "the engine is already warm". Borescope inspection at a BMW specialist (£80–£120) is the cheapest insurance.
Rear air suspension (Touring)moderate
Tail sits low overnight; harsh ride; air pump runs constantly
All G31 Touring (rear self-levelling air suspension is standard) · Typical failure 95,000–110,000 miles · £800–£1,400 per side (genuine BMW); aftermarket from £350
Check: Park overnight before viewing — check the rear ride height is level side to side next morning. Listen for the air pump cycling at idle.

Typical asking price:: £11,340–£23,500, median £15,499 (middle 80% and median, cars on Autoza on 29 October 2026)
Fuel economy:: 44–51 mpg real-world for 520d on UK roads (B47 engine)
Vehicle tax:: £200/year standard rate from the second year, hybrids included — the alternative-fuel discount ended on 1 April 2025. A car registered from April 2017 with a list price over £40,000 when new adds the £440/year Expensive Car Supplement in years 2–6 (£640 in all). Cars registered 2001–2017 pay a CO2 band, roughly £20–£790/year (2026/27 rates).
Best years:: 2019, 2020, 2021

Used BMW 5 Series for sale Full 5 Series fault guide Used BMWs

Also compare:

5 Series vs E-Class

Which one suits you

Audi A6

Good for: Buyers prioritising interior quality, long-distance comfort, and quattro all-wheel-drive grip in UK winters.

Less good for: Buyers averse to electronics complexity, anyone who only ever does short city trips (TDI), drivers without tolerance for MIB3 quirks pre-2022.

BMW 5 Series

Good for: Long-distance commuters, motorway drivers, anyone covering 15,000+ miles/year. Excellent depreciation curve from 4 years onwards.

Less good for: Short-trip city driving (DPF issues), drivers who skip routine servicing, anyone unwilling to budget £700–£1,000/year for maintenance.

Frequently Asked Questions

Which is more reliable, the Audi A6 or the BMW 5 Series?

Neither stands out on the MOT measure. Their first-time MOT pass rates sit 0.3 percentage points apart once each is compared against the national rate for cars of the same age, which is too close to call (we name a winner only at 2 points or more). A pass with rectification at the station counts as a pass here, and as a failure in DVSA's own initial-test measure. The MOT checks safety and emissions items, not the engine, clutch or gearbox, so this is one measure of how each car holds up rather than a full reliability verdict. Pick on the specific faults each is prone to instead.

How do the MOT pass rates of the Audi A6 and the BMW 5 Series compare?

83.1% of Audi A6s pass their MOT first time (12,504 tests in DVSA's records) and 82.9% of BMW 5 Series pass their MOT first time (20,829 tests). The national first-time rate is 77.3%, but cars of the Audi A6's age average 76.6% and cars of the BMW 5 Series's age 76.7% — so the Audi A6 runs 6.5 points better than its age group and the BMW 5 Series runs 6.2 points better than its own. A pass with rectification at the station counts as a pass here, and as a failure in DVSA's own initial-test measure.

Which years of the Audi A6 and BMW 5 Series should I avoid?

Audi A6: Pre-2022 infotainment freezes are the most reported complaint on owner forums. Software updates helped, but owners of 2018–2019 cars report they never fully resolved it on the hardware those cars shipped with. The DVSA MOT table on this page rates 2019 registrations above all cars registered that year, so it is not named as a year to avoid. BMW 5 Series: Chain stretch on early B47 diesels is the most discussed issue on owner forums and can be expensive when it happens. Frequency is unknown to us — we hold no recall or failure count for it — so treat it as a reason to check the service history and listen to a cold start, rather than as a fault every early car has. The DVSA MOT table on this page rates 2017 and 2018 registrations above all cars registered those years, so they are not named as years to avoid. Judge a 5 Series by its registration, service history and the checks below rather than by year.

Is the Audi A6 or the BMW 5 Series cheaper to run?

On fuel the two are too close to call: the most economical versions return up to 49 mpg (Audi A6) and 51 mpg (BMW 5 Series), on the figures in our model guides. For cars registered from April 2017, vehicle tax works the same way for both: the £200/year standard rate from the second year, hybrids included, plus the £440/year Expensive Car Supplement in years 2–6 on a car that listed at over £40,000 new — the price when new, not what you pay for it used. Any Audi A6 or BMW 5 Series registered between 1 March 2001 and 31 March 2017 pays a CO2 band instead, roughly £20–£790/year (2026/27 rates). Insurance differs mainly by driver and postcode rather than by model, so treat any model-level insurance figure with caution.

MOT figures are counted from DVSA records and are the only measured statistic here. Prices, economy and tax bands are indicative and vary by specification, condition and where the car has lived. Last reviewed: 2026-10-06 / 2026-10-06.