2018 Audi Q8 3.0L Diesel · A7 DYT

Fuel economy and tax: The 2.9L TDI diesel is a common choice for the Q8, offering decent fuel efficiency for its class (50-55mpg in mixed traffic). However, diesel tax bands are higher than petrol, and with the vehicle’s age, you may be in Band D (£185/year) or potentially Band C if it’s been kept in good condition. Insurance groups for the Q8 vary widely, but the 2018 model in this trim is likely in Group 25-30, which can push annual insurance costs to £1,000-£1,500 depending on the buyer’s profile and additional cover. Maintenance costs: Diesel vehicles of this age can incur higher maintenance costs, particularly for turbochargers, DPFs, and emissions-related components. The Q8’s diesel systems are prone to DPF blockages, which can cost £800-£1,500 to clear, and turbo failures are less common but possible. Annual maintenance budgets should account for £500-£800 in routine servicing, with potential surprises if the brake system or suspension needs attention. The estimated annual running cost for this vehicle, factoring in fuel (£1,200-£1,500), tax (£185), insurance (£1,200), and maintenance (£600), would likely sit in the £3,185-£4,285 range—higher than a petrol Q8 but comparable to other diesel Audis of similar age and mileage.

MOT-specific checks to prioritise: The 2024 MOT failure for nearside front tyre wear (5.2.3 (e)) suggests the vehicle may have been driven unevenly or had misaligned wheels. Inspect the tyres for cracks, bulges, or uneven tread wear beyond the legal minimum (1.6mm). The rear brake pads were also under scrutiny in 2023 and 2024—check for thin pads, warped discs, or excessive heat discolouration, which could indicate a failing system. The MOT history shows no other critical failures, but this doesn’t rule out issues like worn suspension components (struts, bushings), or electrical faults (e.g., brake lights, ABS sensors). Model-specific weak points:

• Diesel particulate filter (DPF): The 2.9L TDI is prone to DPF blockages, especially if the vehicle has been driven at high speeds or in stop-start traffic. A DPF test (£50-£100) can confirm its status—if it’s clogged, expect a costly replacement (~£1,000+).
• Turbocharger: While less common, turbo failures can occur in diesel Audis, particularly if the engine has been driven aggressively. Listen for whining noises or reduced power at higher RPMs.
• Infotainment system: The Q8’s digital interfaces can be finicky. Test all controls, screens, and connectivity (e.g., Bluetooth, satellite navigation) to avoid a £500-£1,000 repair bill later.