The 2023 C3 Aircross diesel is a small crossover based on the C3 hatch with five seats and a reasonably practical boot — dealers sometimes mislabel body-type, but this is a passenger SUV. Diesel variants commonly use a modern BlueHDi engine with DPF and an AdBlue dosing system, so it's best suited to buyers who do regular longer runs; the manual gearbox is simple and cheaper to maintain but watch clutch condition on cold-start city use.

• DPF and AdBlue system — ensure there are no persistent warning lights, check for excessive soot or history of short-trip use that can block the DPF, and confirm the AdBlue filler and cap are intact.
• Clutch condition and pedal bite — test for slipping under load and check the bite point (manual clutch wear can show by 3 years if used heavily in town).
• Manual gearbox selection and syncros — listen for crunching or grinding when changing gears and check for smooth engagement in all ratios.
• Turbo/EGR soot symptoms — watch for black smoke on acceleration, hesitation, or rattles which can indicate soot build-up or turbo issues affecting diesel performance.
• Rear seat mounts and boot area — check ISOFIX anchors, seat-fold mechanisms and boot floor for heavy wear or water ingress if the previous owner used roof-boxes or family equipment.