2019-present · 1.5L B38 3-cylinder turbo petrol (140 hp)
BMW's entry-level hatchback on the new front-wheel-drive UKL2 platform shared with MINI. The B38 three-cylinder engine is generally reliable with proper maintenance, though timing chain tensioner and DCT gearbox behavior require attention. Infotainment software glitches are common on early cars, but fixable with dealer updates. Real-world fuel economy averages 6.9 L/100km (34-42 mpg). Main concerns: timing chain rattle on cold start, DCT jerkiness at low speeds, carbon buildup on direct injection valves, and higher-than-expected oil consumption in some units. Compared to the rear-wheel-drive F20 predecessor, the F40 offers more interior space but less driving engagement.
The B38 engine timing chain tensioner has a release valve that can weaken over time, allowing oil pressure to bleed off when the engine sits overnight. This causes a distinctive rattle for 1-30 seconds on cold start, typically appearing between 60,000-100,000 km. The timing chain is at the back of the engine requiring engine removal for access. UK costs range £1,000-3,000 depending on dealer vs specialist. The chain, guides, tensioner, and sprockets should all be replaced together. Ignoring persistent rattle can lead to chain skip and catastrophic valve damage.
DCT gearbox jerky behavior€0 - €3,500
7-speed DCT exhibits jerky shifts when cold and at low speeds · more· less
The Getrag 7DCT300 transmission used in 118i models is known for jerky behavior at low speeds and when cold, often "hopping" in low gears through town. It can almost stall when braking hard to a standstill when cold. Clunking when shifting from P to D when warm is considered normal. This is characteristic behavior of this DCT design, not necessarily a fault. However, if transmission fluid leaks develop or mechatronics fail, repair costs can reach €3,500. Oil changes at 40-45k km improve smoothness. Manual gearbox models avoid these issues entirely.
Infotainment software glitches€0 - €200
Early F40 models have OTA update issues, Android Auto problems, occasional rebooting · more· less
Early F40 cars (especially Sept 2019 builds) have software preventing over-the-air updates from working. BMW dealers can force through updates to enable future OTA capability. Android Auto is not available on F40s built before July 2020 (iDrive 6), and even post-July 2020 cars need expensive option packages (Connected Package Professional, Live Cockpit Professional) for Android Auto. Some cars experience iDrive rebooting every 20-30 seconds, fixable with dealer software reset. One known cause was Absolute Radio DAB transmission. Dealer software updates typically resolve these issues at minimal cost.
Water pump failure€700 - €1,400
Electronic water pump/thermostat typically fails at 50,000-80,000 km · more· less
The B38 uses an electronic water pump integrated with the thermostat housing. Failure is common between 50,000-80,000 km causing coolant warnings, overheating, or poor cabin heating. Parts cost €400-600 for the integrated unit with approximately 4-6 hours labor due to accessibility issues. This is a known BMW weakness across their electric water pump engines. Replacement is recommended preventatively at 60,000 miles to avoid being stranded. Use BMW or Pierburg parts (Pierburg manufactures for BMW).
Carbon buildup on intake valves€700 - €1,200
Direct injection causes carbon deposits leading to rough idle and power loss · more· less
Direct injection engines like the B38 lack fuel washing over intake valves, allowing carbon and varnish buildup. Symptoms include rough idle, sluggish throttle response, loss of power, and increased fuel consumption. Professional walnut blasting typically costs €700-1,200 including new intake manifold gaskets. BMW dealers charge closer to €1,000+. Unlike older N54/N55 engines, B-series engines appear less prone to severe carbon buildup but walnut blasting around 100,000 km is still recommended preventative maintenance. Oil catch cans can reduce future buildup.
Battery drain issues€150 - €400
Increased battery discharge from modules not sleeping or aftermarket devices · more· less
The "Increased battery discharge while stationary" message indicates electrical equipment consuming excessive current while parked. Common causes include aftermarket dashcams, faulty Intelligent Battery Sensor, defective modules (junction box, comfort access), or devices plugged into 12V outlets. Normal parasitic draw is 50-85mA; over 100mA drains the battery rapidly. New battery must be registered with vehicle computer or premature failure occurs. Battery replacement costs €150-250 plus coding. F40 owners report Varta 85Ah batteries work well and are easy to code with Bimmerlink app.
Oil consumption€0 - €150
Some B38 units consume up to 1L per 1,500 miles, considered normal by BMW · more· less
BMW states that B-series engines may consume up to 1 liter of oil per 1,500 miles (2,400 km) under certain driving conditions, particularly during the first 10,000 miles break-in period. Oil consumption around 15-20% of B38 owners report experiencing oil leaks or higher consumption. Root causes can include piston ring issues, PCV system malfunctions, or valve cover gasket degradation. Regular oil level checks are essential. Use BMW Longlife-17 spec oil (replaces LL-14) for B38 engines. Cost is mainly for top-up oil unless repair is needed.
Suspension wear€400 - €1,200
Some owners report premature shock absorber wear and suspension noise · more· less
Some F40 owners report firm ride quality, excessive noise over rough roads, and premature suspension component wear. Shock absorber replacement costs €250-580 per pair (parts + labor), though it's recommended to replace pairs. The F40 uses MacPherson struts in front which are more expensive to replace than simple shocks. Wheel alignment is necessary after strut replacement adding €80-120. Shock absorbers typically last 50,000-100,000 miles. The F40's sport-tuned suspension may wear faster than comfort-oriented competitors.
Generally reliable for a modern BMW, but requires proper maintenance
The F40 118i with B38 engine is reasonably reliable when maintained properly. Most issues are software-related or normal wear items. The timing chain and DCT gearbox are the main mechanical concerns to monitor. Following BMW service schedules and using quality fluids is essential. Manual transmission models avoid DCT issues entirely. Overall reliability is mid-table for the class, better than previous generations when serviced correctly.
Pre-Purchase Inspection Checklist
General checks
Service history
Complete BMW dealer or authorized specialist records essential. Verify oil changes every 15,000 km maximum, not BMW's 18,000 km interval.
Tires
Check tread depth, age (date codes), uneven wear patterns. Front tires wear faster on FWD F40.
Cold start
Must start engine completely cold. Listen for timing chain rattle in first 30 seconds.
Body condition
Check for accident damage, paint mismatch. F40 is aluminum-bodied so check for proper repairs.
Test drive
Minimum 20 minutes including varied speeds and conditions to assess DCT behavior.
Specific for this vehicle
Cold start timing chain noise
This is the most critical check. Start engine stone cold and listen for rattle/chatter in first 30 seconds. Persistent rattle beyond 5 seconds indicates tensioner wear requiring expensive repair.
DCT gearbox operation (if automatic)
Drive for 15+ minutes. Some jerkiness when cold is normal, but should smooth out when warm. Clunking P-to-D when warm is characteristic. Check for fluid leaks underneath gearbox area.
Infotainment system test
Test all iDrive functions, Bluetooth pairing, navigation. Ask if OTA updates work. Early 2019 cars may need dealer software update. Check if Android Auto/CarPlay works if important to you.
Check for battery discharge warning
Ask owner if "Increased battery discharge" message appears. Inspect 12V outlet for aftermarket devices. Check if battery has been recently replaced and properly registered.
Oil level and consumption
Check oil level is correct. Ask owner about oil consumption between services. Some oil use is normal but excessive consumption (>1L per 2,000 km) may indicate issues.
Coolant system inspection
Check coolant level and condition. Look for leaks around water pump area (front of engine). Ask if coolant warning lights have appeared. Water pump failure is common at 50-80k km.
Suspension noise test
Drive over rough roads and speed bumps. Listen for excessive knocking or rattling from suspension. Check shock absorbers for oil leaks.
Verify recall completion
Check with BMW using VIN that driver's airbag recall and camshaft bearing cap screw recall have been completed if applicable.
Camshaft bearing cap screws (2019-2020)Verify completed
Contact BMW with your VIN to verify all recalls completed. The camshaft bearing cap screw recall is important - loose screws could cause serious engine damage.
Warranty Status
Factory warranty2 years (expired on 2019-2021 models)
Extended warranty availabilityAvailable from BMW dealers
Typical extended warranty cost€500-900/year depending on age and mileage
Most F40 models from 2019-2021 are now outside factory warranty. BMW extended warranty is available through dealers. Independent warranty providers may offer competitive rates. Check what exclusions apply, particularly for DCT gearbox and software issues.
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.