2018 BMW 340i: common problems and MOT failures
What MOT testers find on the BMW 340i first registered in 2018: we looked at the 627 MOTs these cars had during 2023–2025. Plus known faults and what to look at before you buy one.
Common 2018 BMW 340i MOT failures and advisories
The share of 2018 BMW 340i MOT tests where testers flagged each area, as a fail or an advisory. Rough prices are typical independent-garage costs.
- Tyres21% of testsRough price £70–£150
At the viewing: Check the tread on all four tyres, including the inside edges, and look for cracks or bulges.
- Brakes7% of testsRough price £150–£350
At the viewing: Look for a lip on the disc edges and feel for judder or pulling when braking firmly from about 40mph.
- Seats and seatbelts4% of testsRough price £80–£250
At the viewing: Pull each seatbelt sharply. It should lock, and retract cleanly.
- Lights and electrics3% of testsRough price £10–£80
At the viewing: Ask a friend to check every light, including brake lights and indicators, while you operate them.
- Wipers, windscreen and mirrors3% of testsRough price £15–£250
At the viewing: Check for chips in the driver's view, and test the wipers and washers.
- Suspension3% of testsRough price £120–£400
At the viewing: Listen for knocks over speed bumps, and look behind each front wheel for a snapped coil spring.
Known faults on the 2018 BMW 340i
Reported by owners, mechanics and buying guides for this model and age. Check which engine the car has, as some apply to one engine only.
- 2.0 petrol and diesel
Timing chain wear
The four-cylinder petrol and diesel engines can suffer timing chain wear, especially with late oil changes. A failed chain is an engine-out repair.
At the viewing: Listen for a rattle or whine from the back of the engine, especially from cold. Ask for oil changes on time.
- Diesel
Blocked EGR valve or particulate filter (diesel)
Diesels used mostly for short trips can block the EGR valve or clog the particulate filter, causing poor running.
At the viewing: Ask what journeys it’s done and watch for warning lights or a lack of power.
If it needs doing: DPF clean or regeneration, about £160–£500. ClickMechanic
Noisy differential
A whine from the rear as the car passes you can mean the differential has been neglected.
At the viewing: Ask someone to drive it past you slowly and listen for a whine from the back.
Questions to ask the seller before buying a 2018 BMW 340i
Ask before you travel to see it. A seller who knows the car will have answers, and receipts.
- Has the timing chain been checked or replaced, and have oil changes been on time?
- Can I see the service history and receipts for any big jobs?
Looking at a BMW 340i?
Check the actual car: its own MOT history, mileage and what to ask the seller. Free, no sign-up.
Other years
Every year of the BMW 340i compared
| Year | MOT tests | Most flagged |
|---|---|---|
| 2019 | 250 | Tyres 19% |
| 2017 | 1,451 | Tyres 21% |
| 2016 | 387 | Tyres 17% |
Where this comes from: the DVSA's anonymised results for every MOT test done in Great Britain during 2023–2025, counting the MOTs of BMW 340i cars first registered in 2018. "Flagged" includes advisories, so it isn't the same as a fail rate. How we score