The second-generation 1 Series kept BMW's trademark rear-wheel drive and offered two quite different engines over its production run. Pre-LCI models (2011-2015) use the N13 1.6-litre turbo four-cylinder co-developed with PSA at 170 hp. The 2015 LCI initially kept that 1.6 at 136 hp, and the B38 1.5-litre turbo three-cylinder arrived in July 2015, so not every LCI car is a three-cylinder. The N13 is the more problematic of the two, with timing chain and turbo concerns. The B38 is proving more robust overall but still young enough that long-term data is limited.· more· less
Engaging rear-wheel-drive handlingB38 LCI models more reliable
Chain stretches and tensioner weakens, causing cold-start rattle and potential engine damage · more· less
The N13 engine shares its timing chain design with several BMW engines known for premature wear. The chain stretches over time while the tensioner loses its ability to maintain pressure, particularly overnight. This produces a distinctive rattle on cold start lasting a few seconds to half a minute. Typically appears between 80,000 and 150,000 km, though some cars make it further with diligent oil changes. If the chain skips a tooth, it can cause piston-to-valve contact and catastrophic engine damage. Replacement at an independent specialist costs around €1,000-1,500 (chain, guides, tensioner, sprockets). If engine damage has already occurred, costs can escalate to €2,500 or more. BMW improved the tensioner design in later N13 production runs. The B38 LCI engine does not share this issue to the same degree.
Turbo wastegate rattle and diverter valve failure (N13)
€300 - 1,5002 of 8
Wastegate linkage develops play causing metallic rattle, diverter valve membrane tears · more· less
The N13's turbocharger has two common weak points. First, the wastegate linkage develops play over time, producing a metallic rattle particularly at idle and low revs. A flapper repair kit costs around €50-80 and can be fitted without removing the turbo. Second, the diverter valve uses a rubber membrane that tears with age and heat cycling, causing boost leaks and loss of power. The membrane alone is inexpensive (€30-50) but access can add labor costs. If the entire turbo needs replacement due to internal damage from ingested debris (cracked intake hose pieces), costs rise to €1,200-1,500 at an independent specialist. Typically develops between 60,000 and 100,000 km.
Both the N13 and B38 use an integrated PCV (positive crankcase ventilation) system in the valve cover. The internal membrane cracks over time, causing increased oil consumption, rough idle, and potential misfires. Additionally, the valve cover gasket itself degrades, leading to external oil leaks visible around the top of the engine. BMW often recommends replacing the entire valve cover assembly rather than just the membrane, though aftermarket repair kits exist for the PCV alone. Parts cost €100-250 for an aftermarket cover or repair kit, with labor adding €150-300. Typically appears between 60,000 and 120,000 km.
Electric power steering rack knocking
€800 - 2,2004 of 8
Internal wear causes a metallic clunk over bumps, particularly from the passenger side · more· less
A widespread issue across the entire F20 range regardless of engine. The electric power steering rack develops excessive play between its internal gear components and the EPS motor, causing a metallic clunking noise when driving over uneven surfaces. Some cars were covered under a BMW Quality Enhancement programme, though this was not widely publicized. DIY adjustment of the rack's preload bolt can sometimes eliminate the noise for minimal cost. If a new steering rack is required, expect €1,500-2,200 fitted at an independent specialist, or up to €2,700 at a BMW dealer. Typically develops between 40,000 and 80,000 km. Check whether the Quality Enhancement repair has been performed.
Water pump and thermostat housing failure
€400 - 8005 of 8
Coolant pump or plastic thermostat housing fails, typically after 80,000 km · more· less
The N13 drives its main coolant pump mechanically through a friction gear and adds a separate electric auxiliary pump for turbocharger cooling. Both engines use a plastic thermostat housing that degrades with heat cycling. The thermostat housing is known to crack and leak coolant. The main pump can develop bearing noise and the auxiliary pump can fail electrically. Symptoms include coolant warning light, engine overheating, or poor cabin heating in winter. Specialists recommend replacing both components together since they share the same cooling circuit and have similar lifespans. Parts cost approximately €200-350, with labor around €200-450 depending on accessibility. Common between 80,000 and 130,000 km.
High-pressure fuel pump failure (N13)
€500 - 1,0006 of 8
HPFP fails causing hard starting, stalling, or loss of power · more· less
The N13 engine's high-pressure fuel pump can fail, typically between 60,000 and 100,000 km. Symptoms include difficult starting, engine stalling, and loss of power under acceleration. The fault code 11A002 (high pressure fuel plausibility) is commonly associated with this issue. A replacement pump costs €350-600 for the part, with labor around €150-400 depending on the workshop. Using quality fuel and maintaining regular service intervals helps extend pump life. This issue is specific to the N13 and does not affect the B38 LCI models.
VANOS solenoid failure
€200 - 5007 of 8
Solenoid valves clog or fail, causing rough idle, poor performance, and cold-start issues · more· less
The VANOS variable valve timing solenoids on both the N13 and B38 can become clogged with oil sludge or fail electrically. Symptoms include rough idle, reduced power particularly at low revs, poor fuel economy, and extended cranking on cold starts. The solenoids are relatively accessible and affordable to replace: parts cost approximately €80-150 per solenoid (two are used), with around one hour of labor. Regular oil changes with quality oil significantly reduce the likelihood of this issue. Most commonly appears between 60,000 and 100,000 km.
Window regulator failure
€200 - 4008 of 8
Window motor or regulator mechanism fails, typically after 60,000 km · more· less
Electric window regulators on the F20 are a known weak point, particularly on the driver's side due to higher usage. The mechanism can fail (window drops into door panel or moves slowly) or the motor burns out (no response when pressing the switch). A replacement regulator costs €80-150 for the part, with about one hour of labor. Some owners report this happening as early as 60,000 km, though 80,000-120,000 km is more typical.
Engine choice matters: N13 needs more attention than B38
The BMW 118i F20's reliability depends heavily on which engine it has. Pre-LCI cars with the N13 require closer attention to the timing chain, turbo components, and cooling system. LCI models with the B38 three-cylinder have proven more robust overall, with fewer major issues reported. Regardless of engine, the steering rack knocking affects many F20s and should be checked on any prospective purchase. With proper maintenance and proactive monitoring of known weak points, the 118i can provide reliable service.
Service history
Complete BMW dealer or specialist records essential. Verify oil changes at maximum 15,000 km intervals.
Oil level and condition
Check dipstick for level and colour. Dark or gritty oil suggests overdue service. Low oil may indicate consumption issues.
Cold start
Must start the engine completely cold. Listen carefully during the first 30 seconds for any rattling or unusual sounds.
Test drive
Minimum 20 minutes including varied road surfaces and speeds. Check for warning lights, vibrations, and gear changes.
Specific for this vehicle
Identify the engine: N13 or B38
Check the VIN or engine cover. Pre-LCI cars and early LCI cars have the N13 four-cylinder; the B38 three-cylinder arrived in July 2015. This determines which issues to focus on.
Listen for timing chain rattle on cold start (N13)
Start the engine cold and listen for rattling in the first 30 seconds. Any rattle longer than 2-3 seconds indicates chain stretch. This is the most critical check on N13 cars.
Check for steering rack knocking
Drive slowly over speed bumps and uneven surfaces. Listen for metallic clunking from the passenger side footwell area. Ask if the Quality Enhancement repair was performed.
+ 4 more checksShow less
Inspect for coolant leaks
Check around the thermostat housing and water pump area for coolant traces. Low coolant level or a sweet smell from the engine bay are warning signs.
Check turbo response (N13)
Accelerate from low revs in 3rd gear. The turbo should build boost smoothly. Hesitation, surge, or an EPC/drivetrain warning suggests wastegate or diverter valve issues.
Test all windows
Operate all four windows fully up and down. Listen for grinding or slow movement, which indicates regulator wear.
Check for oil leaks around valve cover
Look at the top of the engine for oil residue around the valve cover gasket area. Smell for burning oil, which indicates a leak dripping onto the exhaust manifold.
Improperly welded electric power steering contacts, possible loss of steering assistance (December 2016 recall, narrow VIN subset of F20/F21 built July 2011 - June 2016, about 50 cars in Germany and 500 worldwide)Verify completed
Contact BMW with the VIN to verify all recalls have been completed. The Takata airbag recall is particularly important and has been expanded multiple times — confirm even if a previous check showed clear.
Warranty Status
Factory warranty (2 years)Expired on all used F20 118i models
Warranty term by marketUK cars had 3 years with unlimited mileage through the F20 period; Germany added a third year from November 2016. Expired on all used cars.
Rust perforation warranty (12 years)May still apply on 2014+ models — verify with BMW
All BMW 118i F20 models are well outside their original factory warranty. BMW's 12-year rust perforation warranty may still be valid on later production cars. Third-party extended warranties are available but many explicitly exclude N13 timing chain issues as a known defect.
Sources: Research draws on model-specific owner forums and owner communities, recall information from official authorities, German automotive press, and multiple workshop cost references cross-checked against each other.
This report is for informational purposes only and does not constitute professional advice. Estimates may be inaccurate. Always have a qualified specialist inspect the vehicle before purchase. We accept no liability for decisions made based on this information.
