BMW 418d common problems and MOT failures
What goes wrong on a used BMW 418d, year by year: known faults from UK buying guides, the parts flagged at MOT more than on other cars (from 2,950 MOTs done during 2023–2025), and what to check before you buy one.
Pick the year
Most years have their own guide. The year is when the car was first registered (it’s on the logbook, or check the reg below).
What usually goes wrong with a BMW 418d?
Known faults reported by owners, mechanics and UK buying guides, in our own words. Most apply to certain years or engines only, so check which the car has.
- Cars registered 2014–2017 · 2.0 petrol and diesel
Timing chain wear
The four-cylinder petrol and diesel engines (shared with the 3 Series) 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.
Source: Parkers: BMW 3 Series (2012-2019) used review (the 4 Series shares its engines and running gear)
- Cars registered 2014–2017 · 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
Source: Parkers: BMW 3 Series (2012-2019) used review (the 4 Series shares its engines and running gear)
- Cars registered 2014–2017
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.
Source: Parkers: BMW 3 Series (2012-2019) used review (the 4 Series shares its engines and running gear)
Common BMW 418d MOT failures to check
Parts flagged at MOT well above the usual rate for cars the same age. From the DVSA’s results for every MOT done in Great Britain during 2023–2025.
Steering rack inner joints
up to 17.5× usualStands out on cars registered in 2015 and 2016.
Rough price £100–£450 our estimateAt the viewing: On a straight road the steering wheel should sit straight. Listen for knocks when turning, and check the steering feels even.
Transmission oil leaks
up to 9.5× usualStands out on cars registered in 2015 and 2016.
Rough price £80–£600 our estimateAt the viewing: Look under the engine and where the car is usually parked for fresh oil. Ask whether the leak has been looked at.
BMW 418d MOT pass rate by year
Older cars fail more, so compare each year with all cars registered the same year.
Questions to ask the seller before buying a BMW 418d
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?
- Any recent work on the steering rack inner joints? (Flagged at MOT 17.5× as often on the BMW 418d as on other cars the same age.)
- Any recent work on the transmission oil leaks? (Flagged at MOT 9.5× as often on the BMW 418d as on other cars the same age.)
- Can I see the service history and receipts for any big jobs?
Looking at a BMW 418d?
Check the actual car: its own MOT history, whether it already shows these weak spots and what to ask the seller. Free, no sign-up.
Where this comes from: MOT figures are the DVSA’s anonymised results for every MOT test done in Great Britain during 2023–2025, grouped by the year each car was first registered. How many are on the road is from the Department for Transport’s vehicle licensing statistics. Known faults are from UK buying guides, in our own words, with links. How we score