BMW 118d
Modular four-cylinder diesel, successor to the N47. Timing chain now at the front of the engine — the N47's biggest problem is eliminated. EGR and DPF remain wear items.
Economy Diesel
Frugal yes, fun no. The engine keeps up with traffic but every overtake needs a run-up.
Engine Weaknesses 6
Early B47 engines (2014–2016) are prone to premature chain elongation. The tensioner can no longer compensate. Rattling on cold start is the typical warning sign before chain snap and engine damage.
Symptoms: Metallic rattling or clattering on cold start; subsides after warm-up; in advanced cases audible during driving; MIL may illuminate
Overheating and leaking EGR coolers can vaporise glycol and trigger self-ignition. BMW recalled affected vehicles. If coolant enters the combustion chamber, hydraulic lock and engine damage are possible.
Symptoms: Coolant level drops without visible leak; whitish smoke from exhaust; rough idle; MIL; limp mode; rarely smoke from engine bay
With frequent short-trip use the DPF never reaches sufficient regeneration temperature. Soot accumulation blocks the filter and the engine enters limp mode. Long-term, oil level rises due to fuel intrusion.
Symptoms: MIL with message 'Particulate filter fault'; severe power loss; increased fuel consumption; black exhaust smoke on cold start; oil level rising
Common-rail injectors operate at up to 2,500 bar and wear at higher mileages. Knocking noise on cold start and misfires on individual cylinders. Replacement is complex and expensive.
Symptoms: Knocking noise on cold start; fault code 'injection quantity out of tolerance' or 'cylinder X misfire'; stumbling; increased consumption
From about 150,000 km onwards, failures of the electronic thermostat and electric water pump become more frequent. Overheating without early warning is possible. Replacing both parts simultaneously is recommended.
Symptoms: Coolant temperature rises unusually quickly or too high; heater blows cold; fault codes relating to the water pump; rarely a sudden failure
Primarily urban short-trip use causes the EGR valve to coke up. Power loss and increased emissions.
Symptoms: Power loss, rough running, engine check light, black smoke
Vehicle Weaknesses 7
The electronically controlled water pump in B38 and B48 engines can fail and cause overheating. The thermostat can also stick. Catching it early prevents engine damage.
BMW issued a recall on F40 models for faulty motor position sensors in the electric parking brake. The fault can cause the brake to release unintentionally.
The steering rack can develop clicking or scraping noises. BMW revised the pressure pad. In isolated cases a full rack replacement is necessary.
Windscreen wipers squeak loudly when in use, loose door seals, and generally criticised interior quality given the price point. Minor connectivity and software issues with CarPlay/Bluetooth.
According to TÜV reports, the parking brake on the F40 fails inspection more frequently. Otherwise the F40 is considered a relatively reliable generation with few typical weak points.
The 7-speed dual-clutch gearbox (DKG/Steptronic) on the F40 jerks noticeably when creeping and manoeuvring. Most pronounced at low temperatures and in stop-and-go traffic.
Rattling from the front axle area reported on the F40, attributed to worn anti-roll bar bushings or control arm bushings. Typically appears from 60,000 km.