1. INTRODUCTION

Thank you for using our cost-of-ownership calculator and guide. The 2018 Bentley Mulsanne (3Y_) with its powerful 6.8-litre engine represents the pinnacle of British luxury motoring, blending opulent craftsmanship with effortless performance. This article delves into the real-world cost of owning this flagship sedan in the United Kingdom, covering everything from market pricing and depreciation to maintenance, fuel costs, and common reliability issues. With a mileage of 100,000 km, we'll focus on practical insights for potential buyers or current owners, helping you make an informed decision on this high-end vehicle.

2. ESTIMATED MARKET PRICE

In the United Kingdom, the 2018 Bentley Mulsanne (3Y_) commands a premium in the used luxury car market. For a new vehicle back in 2018, prices started around £220,000. Today, with 100,000 km on the odometer, a well-maintained used example in good condition typically sells for £80,000 to £110,000. Certified pre-owned (CPO) models from Bentley dealers, which include extended warranties and inspections, range from £100,000 to £130,000, offering better peace of mind. Prices can vary based on specifications, service history, and location, with higher-end Mulliner editions pushing towards the upper limit.

3. DEPRECIATION — PAST YEAR

Over the past year, the 2018 Bentley Mulsanne has experienced moderate depreciation in the UK market, losing approximately £10,000 to £15,000 in value for a 100,000 km example. This equates to a 10-15% drop, influenced by broader luxury car market trends, rising interest rates, and increased availability of newer models like the Flying Spur. Well-serviced cars with full Bentley history hold value better, depreciating closer to 10%, while those with incomplete records can see up to 18% loss.

4. DEPRECIATION FORECAST

Looking ahead, the Mulsanne's depreciation is expected to slow as it ages into classic status. Over the next year, anticipate a further 8-12% value loss, bringing resale to £70,000-£100,000. In three years, with mileage around 130,000-150,000 km, it could depreciate by an additional 20-25% cumulatively, reselling for £60,000-£85,000. By five years, total depreciation might reach 40-50%, with estimated resale values of £50,000-£75,000, assuming regular maintenance. Factors like fuel prices and electric vehicle incentives could accelerate this for large-engined cars.

5. BREAKDOWN FREQUENCY & REPAIR COSTS

The 2018 Mulsanne has a relatively low breakdown frequency for a luxury vehicle, with owners reporting issues every 15,000-20,000 km if properly maintained. However, when problems occur, they are costly due to the bespoke nature of Bentley parts. Average repair bills in the UK range from £1,500 for minor fixes to £10,000+ for major components. Annual unexpected repair costs average £2,000-£4,000, higher than mainstream cars but on par with rivals like Rolls-Royce.

6. ENGINE RELIABILITY & REPAIR COSTS

The 6.8-litre twin-turbo V8 engine in the 2018 Mulsanne is renowned for its smoothness and power (505 hp), earning a reliability rating of 7/10 for this mileage (100,000 km). It's built to last, but at this odometer point, wear on turbos and seals becomes evident. Common issues include turbocharger failures (£5,000-£8,000 to repair), coolant leaks from the intercooler (£2,500-£4,000), and variable valve timing problems (£3,000-£5,000). Oil consumption can rise, requiring top-ups between services. With diligent maintenance, major engine overhauls are rare before 200,000 km, but neglect can lead to £15,000+ rebuilds.

7. TRANSMISSION & GEARBOX RELIABILITY

Paired with an 8-speed ZF automatic transmission, the Mulsanne's drivetrain scores 8/10 in reliability. It's smooth and durable, but at 100,000 km, solenoid failures or torque converter issues can arise, costing £2,000-£4,000 to diagnose and fix. Full gearbox rebuilds, though uncommon, run £8,000-£12,000 in the UK. All-wheel-drive components are robust, with differential problems rare (£3,500 repair). Regular fluid changes every 60,000 km prevent most issues.

8. ELECTRICAL SYSTEM & MULTIMEDIA RELIABILITY

The Mulsanne's electronics, including the advanced infotainment system with navigation and 19-speaker audio, rate 6/10 for reliability. At 100,000 km, battery drain from faulty modules (£500-£1,500) and infotainment glitches (£1,000-£2,500 software/hardware fixes) are common. Sensor failures in parking aids or adaptive cruise control cost £800-£2,000 each. UK owners report occasional touchscreen freezes, resolvable via updates at dealers for £300-£600.

9. SUSPENSION & CHASSIS RELIABILITY

With air suspension, the chassis earns a 7/10 reliability score. Common wear at 100,000 km includes air strut leaks (£1,200-£2,000 per corner) and bushings (£800-£1,500). Full suspension refresh costs £5,000-£8,000. The rigid chassis holds up well, but pothole-prone UK roads accelerate bushing wear. Anti-roll bar links (£400-£600) are frequent replacements.

10. BODY & EXTERIOR

Bentley's paint quality is excellent, with a 9/10 corrosion protection rating thanks to galvanised steel and underbody treatments—rust is rare even in damp UK climates. Spare parts availability is good through dealers but pricey: bumpers (£3,000-£5,000), fenders (£2,500-£4,000), windscreen (£1,500-£2,500), and chrome trim (£800-£1,500 per piece). Aftermarket options are limited, increasing costs for body repairs.

11. SCHEDULED MAINTENANCE COSTS

For the 6.8-litre engine at 100,000 km, Bentley's recommended service interval is every 15,000 km or annually. A major service costs £1,500-£2,500, including oil change (10W-40 synthetic, £300-£500), filters (£200-£400), spark plugs (£400-£600 for a set), and brake pads (£800-£1,200 front/rear). The timing chain is maintenance-free but inspected (£500 if adjusted). At this mileage, expect a £3,000-£4,000 comprehensive service including belts and fluids.

12. TAXES, REGISTRATION & INSURANCE

In the UK, annual vehicle excise duty (VED) for this high-emission V8 is £580 (Band M). First-year registration for used cars is minimal (£55), with ongoing MOT tests at £55 annually. Average comprehensive insurance for a 100,000 km Mulsanne is £2,500-£4,000 per year, depending on driver profile and location—higher in urban areas like London due to theft risk.

13. FUEL / ENERGY COSTS

The 6.8-litre V8 averages 14-16 L/100km combined (18-20 mpg), worse in city driving. At current UK petrol prices of £1.45/L, monthly fuel for 1,000 km is £200-£230, or £2,400-£2,760 annually. For heavier use (15,000 km/year), expect £4,000-£4,500.

14. TYRES

Factory-recommended sizes are 265/50 R20 front and 285/45 R20 rear. OEM Bentley/Pirelli tyres cost £300-£400 each, so a full set is £1,200-£1,600. Quality alternatives like Michelin Pilot Sport 4S are £250-£350 per tyre (£1,000-£1,400 set), offering similar performance with better wet grip for UK roads.

15. FILTERS & CONSUMABLES

Cabin air filter: £50-£100. Oil filter: £30-£60. Air filter: £80-£150. Brake fluid: £20-£40 per flush. Wiper blades: £40-£60 pair. These are dealer-priced; independents offer 20-30% savings, but use OEM for warranty.

16. TOTAL ANNUAL OWNERSHIP COST

Summary of Yearly Costs (for 15,000 km usage)
  • Depreciation: £10,000-£15,000
  • Maintenance & Repairs: £3,000-£5,000
  • Fuel: £4,000-£4,500
  • Insurance: £2,500-£4,000
  • Taxes & Registration: £600-£700
  • Tyres & Consumables: £800-£1,200
  • Total: £20,900-£30,400

17. PROS & CONS

Pros
  • Unparalleled luxury and comfort for long journeys
  • Powerful, refined 6.8-litre engine with effortless performance
  • Timeless design and high build quality
  • Strong resale value retention for well-maintained examples
  • Excellent ride quality with air suspension
Cons
  • Extremely high running costs, especially fuel and maintenance
  • Poor fuel efficiency in an era of green incentives
  • Expensive repairs due to specialist parts and labour
  • Limited practicality for families (boot space is adequate but not class-leading)
  • High insurance and road tax premiums

18. WHAT TO CHECK BEFORE BUYING

Before purchasing a 2018 Mulsanne with 100,000 km and the 6.8 engine, inspect the service history for full Bentley dealer records—gaps could indicate neglected turbo or suspension work. Test for smooth engine operation, checking for oil leaks or unusual noises from the V8. Verify transmission shifts are seamless without hesitation. Examine air suspension for leaks (listen for compressor cycling). Scan electronics for error codes, and check bodywork for accident repairs. A pre-purchase inspection by a Bentley specialist (£500-£800) is essential to uncover hidden issues like electrical gremlins or chain tensioner wear.

19. VERDICT

The 2018 Bentley Mulsanne (3Y_) 6.8 is worth its price for those seeking ultimate luxury and status, but only if you can afford the steep ownership costs—it's not for budget-conscious buyers. Reliability is solid for a high-end car when maintained properly, with the engine and chassis holding up well at 100,000 km. We recommend buying if you value bespoke craftsmanship and have access to a trusted Bentley service network; avoid if fuel efficiency or low running costs are priorities. Overall, a qualified buy for enthusiasts, scoring 8/10 for luxury but 5/10 for economy.