BMW 5 Series vs Audi A6: Which Used Executive Saloon Should You Buy in Ireland? (2026)

These two have been fighting over the same Irish driveway for twenty years: the M50 commuter who wants something quieter than a Passat, the rep doing 40,000 km a year, the family that wants one big, safe, automatic diesel. Both are excellent. Both will also cost you real money if you buy the wrong year or the wrong gearbox. Here's how they line up in 2026, with Autoza's own listing data rather than guesswork.

What do a used 5 Series and A6 actually cost in Ireland?

Autoza's live listings give the honest picture. The 5 Series pool runs from 2010 to brand-new; the A6 pool is younger, 2014 to 2024. That's why the Audi median is higher — you're not paying a premium for the badge, you're paying for fewer old cars in the mix.

Two things jump out. First, year for year the A6 is often the cheaper car with more kilometres on it — Irish A6s tend to have lived hard as motorway cars, and the 2019–2021 band shows it (€25,950 at ~172,000 km versus €27,990 at ~126,000 km for the BMW). Second, the 530e plug-in is the bargain of the pair: a median of €25,388 buys a 2017-on 530e, while the only A6 plug-ins on the market are 2023 cars at €36,450.

Under €15,000 you're into 2010–2016 5 Series territory (median €9,970, ~238,000 km) or 2014–2018 A6s (median €13,200, ~241,000 km). Both are 240,000 km cars at that money. Budget for the service history, not the paint. Browse the live BMW 5 Series listings and Audi A6 listings to see what's actually available this week, and run any finance figure through the finance calculator before you fall in love with a car.

Which engines matter in Ireland: 520d and 530e vs 2.0 TDI and 40 TDI?

Ignore the brochure. In Ireland, four engines account for almost every used example you'll see.

BMW 520d (F10 2010–2016, G30 2017–2024)

• The volume car. 2.0-litre diesel, 8-speed ZF automatic on nearly all of them (96% of Autoza's 5 Series stock is automatic). Real-world 5.5–6.5 L/100km on the B47-engined G30, per Autoza's owner-reported figures.
• Buy the B47. BMW's later 2.0 diesel (F10 from 2014, all G30s) doesn't carry the timing-chain reputation of the older N47. More on that below.
• Cheap to tax: the G30 520d auto was rated 108 g/km NEDC, which is €190 a year on a pre-2021 registration.

BMW 530e plug-in hybrid (2017-on)

• 2.0 petrol plus a battery that covers a Dublin school run on electric power alone when new; useless for a Galway–Dublin haul unless you plug in at both ends.
• Motor tax €140–€170 a year (Band A1 on either table), and it's the cheapest way into a G30 on Autoza right now. Boot drops to 410 litres from the saloon's 530 because of the battery.

Audi A6 2.0 TDI (C7 2011–2018) and 40 TDI (C8 2018-on)

• The C7 2.0 TDI ultra 190 with the S tronic gearbox was rated 109 g/km NEDC — the same €190 tax as the 520d. Early front-wheel-drive C7s (to about 2014) used the Multitronic CVT instead; avoid it unless the history is spotless.
• The C8 40 TDI is a 204 hp mild-hybrid diesel with the 7-speed S tronic. Rated 112 g/km NEDC (€200) on a 2018–2020 registration — but 145–158 g/km WLTP, which on a 2021-or-later registration is Band C1/C2 at €270–€280. That's the biggest running-cost gap between these two cars, and almost nobody mentions it.
• Quattro is where the A6 earns its money. A 40 TDI quattro on a wet Mayo road in November is a different car from a rear-drive 520d on run-flats. If you live west of the Shannon and drive early, that's a genuine reason to pick the Audi.

Audi A6 50 TFSI e plug-in (2020-on)

• Petrol plug-in with quattro. Rare and pricey used in Ireland — the 2023 cars on Autoza sit at a median of €36,450. The right car for a company driver; check its exact CO2 on the motor tax calculator before assuming Band A1.

Which is cheaper to run: motor tax, servicing and the faults people actually report?

Motor tax first, because it's the one figure you can pin down exactly. Ireland has two tables — NEDC for cars first registered July 2008 to December 2020, WLTP for January 2021 onward — and the same band letters mean different money on each (Department of Transport rates effective 1 January 2021, gov.ie, accessed September 2026).

CO2 figures vary with wheel size and spec, so treat the table as the typical case and confirm the exact registration in our motor tax calculator — the full band tables are in our motor tax guide.

Company-car BIK: this is where the plug-ins win

Revenue's benefit-in-kind charge is set by CO2 category (Tax and Duty Manual Part 05-01-01b, updated December 2025). A 520d or 40 TDI at 100–139 g/km is Category C: 30% of OMV at low business mileage, falling to 12% above 48,001 km. A 530e or 50 TFSI e under 60 g/km is Category A: 22.5% falling to 9%. The €10,000 OMV reduction applies to both through 2026 and drops to €5,000 in 2027. Plug-ins get no extra relief beyond their category — but the category gap alone is worth thousands a year to a Category C driver.

Servicing and the faults commonly reported

Both are premium cars with premium bills. Independent labour in Ireland runs about €70–€110/hr and main dealers €110–€160/hr (Autoza's verified 2026 Irish rate card), so a good BMW or Audi specialist is worth finding before you buy, not after.

• BMW N47 timing chain (early F10 520d, roughly 2010 to mid-2011). The most-reported 5 Series fault of the era: the rear-mounted chain can stretch and fail, and because it's at the gearbox end it's an engine-out job commonly quoted at €3,000–€5,000 at an independent engine specialist (Autoza's BMW 5 Series faults guide, 2026). BMW revised the design from around March 2011 and moved to the B47 engine from 2014. Confirm engine code and build date by VIN, not plate year.
• BMW diesel EGR cooler recall (2018 onward). Covered a wide run of 2010–2017-era diesels for a coolant-leak fire risk. Ask the dealer to show the recall as completed; it's free.
• Audi Multitronic CVT (front-drive C7 to ~2014). Judder at low speed and, eventually, loss of drive are commonly reported. Walk away from one that shudders pulling away.
• Audi S tronic DL501 mechatronic (C7 quattro, C8). Sticking gears, no reverse or limp mode are the commonly reported symptoms, usually on higher-mileage cars. Irish gearbox specialists quote €900–€1,800 for a rebuild versus €1,400–€2,800 for a dealer unit; a DSG oil-and-filter service is a different, far cheaper job at €350–€500 for the 7-speed.
• Audi C8 MIB3 infotainment freezes (2018–2021). Free under software update, €350–€800 if the MMI hardware needs swapping (Autoza's Audi A6 faults guide). The 2022 facelift sorted it.
• Diesel DPFs, both cars. A short-trip diesel of either badge will block its filter. A specialist clean is €250–€700; a dealer replacement is €1,000–€3,000 (Irish DPF specialist pricing, Aug 2026). If your commute is under 15 km, buy the 530e instead.

Neither needs a timing belt — both 2.0 diesels are chain-driven — so the scheduled big-ticket item is the automatic gearbox oil at roughly 60,000 km on the Audi and whatever your BMW specialist recommends for the ZF 8-speed (BMW calls it sealed for life; specialists don't).

Which is better to live with?

• Driving: BMW. Rear-wheel drive, near 50/50 balance and the ZF gearbox make the G30 the best-driving big saloon at this money. The A6 is quieter and more relaxed; pick it if the M7 at 6am is your idea of a drive.
• Cabin and tech: Audi, narrowly. The C8's twin touchscreens and Virtual Cockpit still look newer than a G30's iDrive — though iDrive is easier to use with cold hands and never freezes.
• Boot: a dead heat at 530 litres for both saloons. The A6 Avant estate takes 565 litres, and in our experience A6 estates are easier to find in Ireland than 5 Series Tourings. Plug-in versions lose space to the battery: 410 litres in the 530e, 405 litres in the A6 Avant TFSI e.
• Wet roads and winter: Audi if you can find a quattro; most Irish 520ds are rear-drive and many sit on run-flat tyres, which are pricier per corner and harsher on a boreen.
• Supply and choice: BMW, comfortably. The 5 Series is one of the most-listed automatic executive cars on Autoza, which means more choice and more room to negotiate. See the full best automatic cars in Ireland round-up for where it sits.

Head-to-head: the verdict table

The honest caveat: at 150,000–200,000 km — which is where most of these cars are — the badge matters far less than the last three owners. A 2018 A6 with a folder of stamps beats a 2019 520d with a gap in its history every time. Get an independent inspection (€300–€500 for a car like this), check the NCT history, and read our 10-step pre-purchase guide before you hand over a deposit. Trading one in? Get a free figure from Autoza's car valuation tool first.

If you're cross-shopping wider, our BMW 5 Series vs Skoda Superb piece covers the value alternative, and BMW 3 Series vs Audi A4 is the same fight one size down.

Frequently Asked Questions

Is a used BMW 5 Series or Audi A6 cheaper in Ireland?

On Autoza in September 2026 the median asking price is €22,950 for a 5 Series and €25,950 for an A6, but the A6 stock is newer (2014–2024 versus 2010–2026). Year for year, a 2016–2018 A6 (median €20,394) and 520d (median €19,450) are within about €1,000 of each other.

How much is motor tax on a BMW 520d?

A G30 520d automatic rated 108 g/km NEDC is €190 a year if first registered 2008–2020; a 2021-or-later car on the WLTP table is typically €210 (Band B2). Early F10 520ds at 119 g/km pay €200. Source: Department of Transport motor tax rates, gov.ie.

How much is motor tax on an Audi A6 40 TDI?

€200 a year (112 g/km NEDC) on a 2018–2020 registration, but €270–€280 on a 2021-or-later registration because its WLTP rating of 145–158 g/km lands in Band C1/C2. The older C7 2.0 TDI ultra S tronic is €190.

Which years of BMW 520d have the timing chain problem?

The N47 chain issue is most commonly reported on early F10 520d/525d cars built from 2010 to roughly mid-2011; BMW revised the chain from around March 2011 and fitted the B47 engine from 2014. An engine-out repair is commonly quoted at €3,000–€5,000 at an Irish independent specialist, so verify the engine code by VIN.

Is the Audi A6 S tronic gearbox reliable?

The 7-speed DL501 S tronic is generally durable but mechatronic faults (sticking gears, no reverse, limp mode) are commonly reported on high-mileage cars. Irish specialists quote €900–€1,800 for a rebuild; insist on evidence of gearbox oil changes at roughly 60,000 km.

Is the 530e worth it over a 520d?

For a short commute with home charging, yes: motor tax is €140–€170, BIK drops from Category C to Category A, and Autoza's 530e median (€25,388) undercuts the 2019-on 520d diesel median (€29,894). For 30,000 km a year of motorway driving, the 520d's diesel economy still wins.

Whichever badge you land on, the right car is the one with the history to back it up — search used vehicles on Autoza and compare live 5 Series and A6 listings side by side.