This is the F10-generation 5 Series (produced until 2016) where the common diesel options are the 2.0-litre (520d) and 3.0-litre (525/530d) engines; automatics are usually the ZF 8‑speed. Diesel F10s can be excellent long-distance cars but some 2.0d engines (N47 family) had timing-chain related issues on earlier examples, and like all diesels they can suffer clogged DPFs and EGRs if used mainly for short urban trips. Make sure the ZF auto has had fluid/servicing at sensible intervals — a neglected gearbox service is an expensive item to fix later.

• Timing-chain noise on cold start or heavy acceleration (N47 2.0d): listen for rattle and ask if the chain/tensioner was replaced.
• DPF/EGR health — check for excessive soot or visible smoke and ask whether the car has seen regular long runs to allow DPF regen.
• Automatic gearbox shifts — check for smooth, prompt gear changes and ask if the gearbox fluid/servicing has been done (ZF 8HP needs attention if neglected).
• Turbo and injection behaviour under load — watch for black/blue smoke, hesitation or surging which can indicate turbo, injector or HP fuel-pump issues.
• Suspension and steering knocks or uneven tyre wear at the front/rear (bushes, drop links or steering rack wear are common on older 5 Series).