Audi A6 vs Mercedes-Benz E-Class: which is the better used buy?

On DVSA MOT records the Audi A6 is the more reliable used buy: it passes its first MOT 3.3 percentage points more often than the Mercedes-Benz E-Class once both are compared against what the national fleet scores at the same age. That comparison covers 36,417 real tests, not a survey.

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.

Model	Pass rate	Age-matched national	Difference	Tests
Audi A6	83.1%	76.6%	+6.5	12,504
Mercedes-Benz E-Class	80.2%	77%	+3.2	23,913

Source: DVSA MOT Anonymised Data 2025 (Open Government Licence v3.0). National first-time pass rate 77.3%. Applies to Great Britain — Northern Ireland is tested by the DVA under a separate manual.

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 Haldex pump wear on quattro variants near 60,000 miles. The 2022 facelift fixed the infotainment. Best-buy years: 2022–2024. Worst: 2018–2019.

What goes wrong

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.
Haldex pump (quattro)moderate
Loss of all-wheel drive feel; transmission fault codes; "drivetrain malfunction"
All quattro variants with Haldex (front-biased) · Around 60,000 miles · £450–£700 pump replacement + Haldex fluid service
Check: Service history should show Haldex fluid change every 35,000 miles. Diagnostic scan should show no Haldex codes.
MHEV 48V battery faultsminor
Stop-start system disabled; "Mild Hybrid" warning; reduced fuel economy
2019+ (when 48V system became standard on most variants) · £800–£1,200 battery pack replacement
Check: Test stop-start engagement at every traffic light during drive. Should engage reliably when warm.

Typical asking price:: £16,000–£45,000 (2018–2024)
Real-world 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. Cars registered 2001–2017 pay a CO2 band, roughly £20–£790/year (2026/27 rates).
Best years:: 2022, 2023
Years to avoid:: 2018, 2019

Full A6 fault guide Used Audis

Mercedes-Benz E-Class

W213, 2016–2023 · premium executive saloon

The W213 Mercedes E-Class (2016–2023) is the most refined of the German big three but suffers from OM654 diesel injector recalls (2017–2019), 9G-Tronic harsh shifts requiring software update, and rear air suspension leaks on Estate variants. Post-2020 examples are most reliable. Best-buy: 2020–2022. Worst: early 2017 OM654.

What goes wrong

OM654 diesel injector recallmajor
Rough idle, smoke under acceleration, rare cases of fuel-air mixture issues
2017–2019 (E220d, E300d, E350d) · Free under recall; £1,800+ if not completed and fault has developed
Check: Verify recall completion via VIN at a Mercedes UK dealer or the gov.uk recall checker. Recall reference: campaign 5499006.
9G-Tronic harsh shiftsminor
Notchy 2-3 and 3-4 upshifts; flare on downshifts
2016–2018 · Free under software update at MB dealer; £600+ if mechatronic affected
Check: During test drive, hold gears manually and observe shift quality. Service history should show software update applied.
Rear air suspension leak (Estate)moderate
Tail end sits low overnight; pump cycles excessively; "AIRMATIC fault" warning
All Estate variants with rear air suspension · 75,000+ miles · £500–£900 per side air bellow + valve service
Check: Park overnight on level ground. Check rear ride height next day. Listen for compressor at idle (pump should rest).
MBUX voice control glitchesminor
"Hey Mercedes" not responding; wake-word recognition errors; UI freeze
2018–2020 · Free under software update
Check: Test "Hey Mercedes" wake-word during inspection. Three failed attempts in a row signals software not updated.

Typical asking price:: £10,000–£40,000 (2016–2023)
Real-world economy:: 42–50 mpg for E220d real-world
Vehicle tax:: £200/year standard rate from the second year, hybrids included — the alternative-fuel discount ended on 1 April 2025. Cars registered 2001–2017 pay a CO2 band, roughly £20–£790/year (2026/27 rates).
Best years:: 2020, 2021, 2022
Years to avoid:: 2017, early 2018

Full E-Class fault guide Used Mercedes-Benzs

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.

Mercedes-Benz E-Class

Good for: Long-distance comfort buyers; motorway commuters; buyers prioritising interior refinement above sportiness.

Less good for: Short-trip city users (DPF on diesel), drivers who don't budget for MB-specialist servicing (£500+ per service).

Frequently Asked Questions

Which is more reliable, the Audi A6 or the Mercedes-Benz E-Class?

The Audi A6. It passes its first MOT 3.3 percentage points more often than the Mercedes-Benz E-Class once both are age-adjusted, across 36,417 DVSA-recorded tests.

What is the MOT pass rate for the Audi A6?

83.1% of Audi A6s pass their MOT first time, from 12,504 tests in DVSA's records. The national first-time rate is 77.3%, but cars of this model's age average 76.6% — so it runs 6.5 points better than its age group.

What is the MOT pass rate for the Mercedes-Benz E-Class?

80.2% of Mercedes-Benz E-Classs pass their MOT first time, from 23,913 tests. Against the 77% that cars of its age average, it runs 3.2 points better.

Which years should I avoid?

For the Audi A6, Pre-2022 infotainment freezes were genuinely dealer-breaking — multiple UK dealers reported buyers returning cars under Consumer Rights Act remedies. Software updates eventually helped but never fully resolved on hardware that shipped in 2018–2019. For the Mercedes-Benz E-Class, The OM654 injector recall affected 2017–2019 diesels — many were left to the second owner to discover. Software-related gearbox harshness was common before the 2019 update.

Which is cheaper to run?

The Audi A6 returns 42–49 mpg for 2.0 TDI; 28–33 mpg for 55 TFSI petrol in real UK driving; the Mercedes-Benz E-Class returns 42–50 mpg for E220d real-world. Vehicle tax: A6 — £200/year standard rate from the second year, hybrids included — the alternative-fuel discount ended on 1 April 2025. Cars registered 2001–2017 pay a CO2 band, roughly £20–£790/year (2026/27 rates).; E-Class — £200/year standard rate from the second year, hybrids included — the alternative-fuel discount ended on 1 April 2025. Cars registered 2001–2017 pay a CO2 band, 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: 2026-08-14 / 2026-08-14.