An F20 BMW 1 Series with the B47 diesel, an automatic gearbox and proof of its EGR cooler recall is the lesser risk; avoid any with a cold-start rattle, as timing chains fail on the N43, N13, B38 and N47.
16 known faults, 13 rated high severity in our database; owners report 42.2 mpg, 78% of the official figure. Everything below is built from that data and the archived owner history, not from a press car.
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Check a BMW 1 Series advert (free) →An F20 with the B47 diesel is the 1 Series carrying the least engine risk, because its known fault, an EGR cooler that can leak coolant and start a fire, is covered by a recall on 2014 to 2018 diesels. Ask for proof that work's been done, and lean towards an automatic, since manual 116d and 118d cars from 2011 to 2017 have known clutch and dual-mass flywheel failures.
Timing chains are the big worry elsewhere in the range. The N47 diesel in 116d, 118d and 120d cars from 2007 to 2015 has a known chain fault at the back of the engine between 70,000 and 110,000 miles, the N43 116i and 118i petrols from 2004 to 2011 have known chain and guide failures, and the F20's N13 and B38 petrols carry known chain faults too, with the B38 also collapsing pistons.
On a 2004 to 2011 E8x, a 118d or 120d from before March 2007 has the older M47 diesel, which is less prone to chain tensioner trouble than the N47 that replaced it, but DSC sensors and reluctor rings are a known failure across the E8x range between 60,000 and 140,000 miles. The six-cylinder 135i isn't a way round it: the N54 has known fuel pump and wastegate faults, and later six-cylinder petrols had their VANOS screws recalled.
The B47 2.0 diesel is the lesser risk, as long as its recall's been done. On 2014 to 2018 engines the EGR cooler can crack and let coolant into the exhaust gas, where the deposits can set fire to the inlet manifold. Losing coolant with no leak you can see, or a burning smell from the engine bay, are the warning signs. Some B47 cars also had a service action that reprogrammed the ECU or fitted a new EGR valve.
Be wary of the N47 diesel. Its chain sits at the back of the engine behind the flywheel, so the gearbox has to come off or the engine come out to reach it, and its guides break up, a known failure between 70,000 and 110,000 miles that can arrive with no warning. There's no fixed replacement interval, so listen for a rhythmic scraping from the rear on a cold start.
The petrols are no safer. The N43 116i and 118i from 2004 to 2011 have known chain faults, with the chain jumping a tooth or its guides breaking up between 20,000 and 75,000 miles, plus known coil pack and injector failures from 2007. The F20's N13 1.6 turbo, in 114i, 116i and 118i cars from 2011 to 2017, sheds bits of plastic tensioner into the sump and starves itself of oil, and the 2015 to 2017 B38 three-cylinder has known piston and chain failures between 20,000 and 35,000 miles.
Manual 118d and 120d E8x cars from 2007 to 2011 have known dual-mass flywheel and clutch failures between 50,000 and 100,000 miles, and F20 manual 116d and 118d cars have failed from as early as 12,000 miles. BMW calls its six- and eight-speed automatics sealed for life, but the listed oil change is at 60,000 miles or 96 months. On a 135i, the N54 has known fuel pump failures and wastegate rattle between 60,000 and 100,000 miles, and the N55's VANOS screws can loosen or snap.
Listen to a cold start with the bonnet up, as the N47, N43 and N13 chain faults can be heard. On an N47 diesel, a rhythmic scraping or metallic rattle from the back of the engine, near the bulkhead, points to the chain. On an N13 petrol, it's a rattle from the front lasting several seconds, and on an N43, a metallic rattle as it fires up. An N54 135i that cranks for ages or rattles from the exhaust side when you lift off has fuel pump or wastegate trouble.
On the drive, a manual diesel that judders pulling away, sends vibration through the pedal or won't go into gear cleanly needs a clutch and flywheel. DSC or DTC warning lights, a jerky ride or power suddenly cutting to the wheels point to failed wheel sensors or reluctor rings. Misfires or rough running on an N43 point to coil packs or injectors, engine emergency mode on a six-cylinder petrol can mean loose VANOS screws, and a flickering instrument cluster suggests the battery cable fault.
Check the bulkhead vent drains on both sides of an F20 aren't blocked with leaves, as water there gets into the wiring. Leave the iDrive running for the whole drive, since blank screens showing just the BMW logo, freezing and random restarts have all been reported. On a three-door E8x, make sure the frameless windows drop and rise properly as you open and shut the doors, and check the power steering fluid level and the track rod end gaiters for fluid seeping from the rack.
Ask for proof of the recalls: the battery cable at the power distribution box on 2007 to 2011 cars, the VANOS screws on 2005 to 2012 six-cylinder petrols, the EGR cooler on 2014 to 2018 diesels, and the replacement brake fluid reservoir cap on F20s. On a 2007 or 2008 N47, look for the chain, guide and tensioner work BMW did under its quality enhancement programme, and check the oil's been changed at least every 10,000 miles, as chain failures have been linked to longer gaps.
Paste the advert into the free check and it runs these against the listing, the MOT history and the DVLA record before you travel.
It's a risky buy unless you choose the engine carefully, because the N43 116i and 118i petrols and the N47 diesels from 2007 both have known timing chain failures. One 2007 116i had chain trouble at 22,000 miles, a 40,000-mile 118i seized when bits of broken plastic guide blocked its oil strainer with no warning light, and one 2009 118i's engine was wrecked at 74,000 miles, leaving the owner with a £7,000 bill even with BMW paying half.
N47 chain failures have been reported at 59,000, 63,000 and 74,000 miles on 2007 and 2008 118d cars, at 67,000 on a 2007 120d, and at 114,000 on a 2011 118d serviced on time at a dealer. BMW has helped some owners: one 2008 120d owner saw a £2,500 bill cut to £1,300, and another got a £2,350 quote on a 118d down to £650, with the dealer and BMW both chipping in.
Manual diesels from 2007 have known dual-mass flywheel and clutch failures, and one 118d went through five of them; BMW first tried software to raise the idle speed, then fitted a redesigned flywheel and clutch to cars still under warranty. Wheel sensors and reluctor rings are a known fault too: one 139,000-mile 120d owner paid £1,500 for both rear driveshafts and sensors, and a 2009 116i owner paid £1,215 for new output shafts and rear sensors after the car slowed to a stop at 43,000 miles.
The E8x scored five stars for occupant protection. Early petrol cars from 2004 to 2007 have had ECU failures, the steering rack can leak fluid into the track rod end gaiters without you noticing, and a 2010 125i convertible lost all four ABS sensors before 30,000 miles. Coupes can let rain into the boot through the vent flaps behind the rear bumper, where it upsets the electrics, so lift the boot floor and check for damp.
Real-world economy on this generation: BMW 1 Series 42.1 mpg, BMW 1 Series Convertible 41.0 mpg, BMW 1 Series Coupe 42.5 mpg, BMW 1 Series 42.4 mpg.
The F20's N13 petrol is its weak spot, with known timing chain tensioner failures from 25,000 miles on 114i, 116i and 118i cars. One 2012 118i owner was quoted £2,800 in parts after broken plastic tensioners dropped into the sump at 52,000 miles. A 2014 116i that had run low on oil lost its chain, guides and oil pump at 50,000 miles, with the owner's £2,500 estimate cut to £685 after BMW helped. A specialist quoted another owner £795 for a rattling chain at 66,000 miles.
The B38 three-cylinder in 2015 to 2017 118i cars doesn't escape either: it has known piston collapses and chain failures between 20,000 and 35,000 miles. One September 2015 118i's piston collapsed at 34,000 miles and its owner was first quoted £10k by the dealer for a new engine, another 2015 car's chain failed at 33,000 miles, and a 2016 118i on sale had already needed a new cylinder head at 20,000 miles.
The N47 diesel's known chain fault runs to 2015 cars, and one 2013 116d had its chain replaced under warranty. Manual 116d and 118d cars have known clutch and flywheel failures from 12,000 to 50,000 miles, and one 2015 118d's clutch and flywheel seized at 12,000 miles. The B47 diesel's EGR cooler was recalled over a fire risk. One 2017 118d automatic started jerking and kicking down at 25,000 miles until a blocked EGR valve was replaced under warranty.
The iDrive screen can go blank, freeze or restart itself, and one 2017 140i was still doing it after a new unit. On F20s, water getting through the brake fluid reservoir cap led to a replacement cap programme, and one 2014 120d xDrive also needed a new DSC hydraulic unit. A stone through the grille damaged the radiator and air-con condenser on one 140i, costing that owner more than £1000. The F20 earned a five-star Euro NCAP rating.
Real-world economy on this generation: BMW 1 Series 42.4 mpg, BMW 1 Series 39.7 mpg.
Sellers rarely admit these faults outright
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Check an advert now (free) →Owners report 42.2 mpg across the BMW 1 Series engines with data, about 78% of the official figure, from 4,453 submissions.
BMW 1 Series Real MPG by engine →The F20's ride and handling are slick, and there's a wide choice of petrol and diesel engines, so it isn't hard to find one that suits how you drive. One 120d Coupe owner found it great to drive at 75mph on the motorway, where it feels safe and secure.
Its nav and media system is packed with tech but still simple to find your way around. Tyres can last well too: one M135i owner covered 30,000 miles on a set of 18-inch runflats, with wider ones on the back than the front.
An F20 BMW 1 Series with the B47 diesel, an automatic gearbox and proof of its EGR cooler recall is the lesser risk; avoid any with a cold-start rattle, as timing chains fail on the N43, N13, B38 and N47. Our database holds 16 known BMW 1 Series faults, 13 rated high severity, and the sections above say which generation and engine carry them.
An F20 with the B47 diesel is the 1 Series carrying the least engine risk, because its known fault, an EGR cooler that can leak coolant and start a fire, is covered by a recall on 2014 to 2018 diesels. On the fault record the F20/F21 (2011 to 2019) carries 7 known faults against 9 on the E81/E87/E82/E88 (2004 to 2011). Each generation's section above gives the detail. BMW 1 Series faults by generation.
Listen to a cold start with the bonnet up, as the N47, N43 and N13 chain faults can be heard. Read the MOT history for repeat advisories and ask for invoices for any work the seller mentions. Then paste the advert into the free check, which reads it against every known BMW 1 Series fault before you travel.
Owners report 42.2 mpg on average, about 78% of the official figure, from 4,453 submissions. Chain (N47, 2.0D, 2.0 DIESEL): no fixed replacement interval, so budget for it if the history does not show it done. The known faults page lists a rough repair cost against each fault. BMW 1 Series Real MPG by engine.
If you used the Honest John car-by-car reviews before the site closed in 2026, this is where the BMW 1 Series buying advice now lives. It is written from the archived owner reports and model notes (archived page, 135 items read for this model), our own known-faults database, the confirmed service intervals and the Real MPG figures. Every number on the page comes from that data, not from the text. The same data feeds our free advert check.
CarAdCheck is not affiliated with Honest John or Volkswagen Financial Services. What happened to Honest John, and where each feature lives now.
The BMW 1 Series is one decision. Reading the advert, the history and the seller are the rest, and these cover them.
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