BMW 1 Series F40Hatchback2019–present
Every engine fitted to the F40-generation BMW 1 Series — from the 1.5-litre three-cylinder petrol to the 2.0-litre four-cylinder and the range-topping M135i xDrive.
Real UK costs, honest failure data, and the switch to front-wheel drive that redefined this generation.
Backed by 344+ real UK 1 Series enquiries in 2025 [BMW-VERIFIED].
Engine Database
Every engine fitted to the F40 1 Series specifically — BMW's first front-wheel-drive 1 Series, powered exclusively by three- and four-cylinder modular engines.
Overview
The BMW 1 Series F40 is the third generation of BMW's entry-level premium hatchback, launched in July 2019. It marked a significant departure from its predecessors (E81/E87 and F20/F21) by switching from rear-wheel drive to front-wheel drive, based on BMW's FAAR platform shared with the Mini and 2 Series Gran Coupé. The F40 is powered exclusively by BMW's modular three- and four-cylinder engines — the B38 1.5-litre petrol three, B48 2.0-litre petrol four, and B47 2.0-litre diesel four — with power outputs ranging from 109 bhp in the 116i to 306 bhp in the M135i xDrive.
A plug-in hybrid variant, the 225xe, combines the B38 petrol with an electric motor for 218 bhp combined output. A 2024 facelift (LCI) introduced revised styling and updated infotainment.
Key Facts
Market Intelligence
The F40 1 Series generated real UK engine enquiries in 2025, with the 2.0-litre B47 diesel and B48 petrol engines accounting for the largest share of BMW 1 Series enquiries (344 total).
04Best & Worst Engines
Best Diesel Overall
B47D20A 2.0-litre (190 bhp) 120d — The 190 bhp B47 diesel delivers excellent real-world performance and economy. Post-recall EGR cooler units are reliable, and the engine is significantly more robust than the N47 it replaced.
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Who it's for: high-mileage buyers who prioritise economy and torque.
Best Petrol Overall
B48A20 2.0-litre (178 bhp) 120i — The 178 bhp B48 petrol offers the perfect balance of performance, economy, and reliability for the F40. No supercharger complexity, no twin-turbo issues — just a well-sorted, modern four-cylinder.
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Who it's for: buyers who want the best all-round F40 petrol.
Highest Risk
B47D20A (pre-EGR recall) — Early B47 diesels (2019–2020) suffer from EGR cooler failure, which can lead to coolant leaks and, in rare cases, fire risk. BMW issued a recall — any car without documented recall work carries this risk.
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Who it's for: only buyers with documented EGR cooler replacement.
Most Expensive Failure
B48A20 (M135i xDrive) — The 306 bhp B48 in the M135i xDrive is the most expensive engine in the F40 line-up to replace, with reconditioned units costing £3,800–£6,500. Cooling system issues (water pump, expansion tank) are the primary risk.
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Who it's for: performance buyers who accept the premium.
Best Value
B48A20 2.0-litre (178 bhp) 120i — The 120i offers the best balance of performance, economy, and running costs. The B48 is well-supported, parts are widely available, and the recon cost is significantly lower than the M135i.
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Who it's for: buyers who want genuine performance without the M135i's premium.
Most Overlooked
B38A15 1.5-litre (136 bhp) 118i — Often dismissed as the "entry-level" F40, the 136 bhp three-cylinder delivers surprising character and genuinely good fuel economy. It's the cheapest F40 to run and the most reliable engine in the range.
“”
Who it's for: buyers who prioritise running costs over outright performance.
Best Diesel Overall
B47D20A
2.0-litre (190 bhp) 120d — The 190 bhp B47 diesel delivers excellent real-world performance and economy. Post-recall EGR cooler units are reliable, and the engine is significantly more robust than the N47 it replaced.
“”
Who it's for: high-mileage buyers who prioritise economy and torque.
Best Petrol Overall
B48A20
2.0-litre (178 bhp) 120i — The 178 bhp B48 petrol offers the perfect balance of performance, economy, and reliability for the F40. No supercharger complexity, no twin-turbo issues — just a well-sorted, modern four-cylinder.
“”
Who it's for: buyers who want the best all-round F40 petrol.
Highest Risk
B47D20A
(pre-EGR recall) — Early B47 diesels (2019–2020) suffer from EGR cooler failure, which can lead to coolant leaks and, in rare cases, fire risk. BMW issued a recall — any car without documented recall work carries this risk.
“”
Who it's for: only buyers with documented EGR cooler replacement.
Most Expensive Failure
B48A20
(M135i xDrive) — The 306 bhp B48 in the M135i xDrive is the most expensive engine in the F40 line-up to replace, with reconditioned units costing £3,800–£6,500. Cooling system issues (water pump, expansion tank) are the primary risk.
“”
Who it's for: performance buyers who accept the premium.
Best Value
B48A20
2.0-litre (178 bhp) 120i — The 120i offers the best balance of performance, economy, and running costs. The B48 is well-supported, parts are widely available, and the recon cost is significantly lower than the M135i.
“”
Who it's for: buyers who want genuine performance without the M135i's premium.
Most Overlooked
B38A15 1.5-litre (136 bhp) 118i — Often dismissed as the "entry-level" F40, the 136 bhp three-cylinder delivers surprising character and genuinely good fuel economy. It's the cheapest F40 to run and the most reliable engine in the range.
“”
Who it's for: buyers who prioritise running costs over outright performance.
Engine
Typical Mileage
Common Major Failure
Repair Cost (Specialist)
Replacement Cost (Recon)
Ownership Verdict
Best Value -reliable, simpleBest Petrol -the sweet spot
Premium Choice -performance costs
Risk vs Reward -check EGR recall statusWatch -battery adds complexityEngineTypical MileageCommon Major FailureRepair Cost (Specialist)Replacement Cost (Recon)Ownership VerdictBest Value -reliable, simpleBest Petrol -the sweet spotPremium Choice -performance costsRisk vs Reward -check EGR recall statusWatch -battery adds complexity
The F40 rule
A £3,800–£6,500 M135i recon against a £12,000–£15,000 early F40 sits at 25–54% of the car's value -on a sub-£12,000 example, that brushes our 70% BMW threshold, and we'll honestly tell you to walk away. Against a well-kept £18,000+ example, the same recon drops to a routine 21–36% -a repair decision, not a financial one. Value the car first.
Key Takeaways
Which F40 Costs Least To Own?
B38 1.5-litre 118i -cheapest recon, simplest architecture.
Which F40 Costs Most To Own?
B48 M135i xDrive -cooling system repairs and xDrive complexity add cost.
Which F40 Is Best Value?
B48 2.0-litre 120i -the sweet spot between performance and running costs.
B47
Diesel EGR Cooler Failure
Affected models:
F40 116d, 118d, 120d, 125d (2019–2020, pre-recall).
Typical failure mileage:
60,000–120,000 miles.
Root cause:
The EGR cooler on early B47 diesel engines can develop internal coolant leaks, leading to coolant loss and, in rare cases, fire risk. BMW issued a recall for this issue -any car without documented recall work carries this risk.
Tiered Cost Table
Preventative (Repair)
Dealer
Specialist
£800–£1,500 (recall work free if applicable)
£500–£1,200
EGR cooler replacement, coolant flush
Catastrophic (Replacement)
Dealer
Specialist
£4,000–£6,000
£2,800–£5,000
Full reconditioned engine
Our Recommendation
On any F40 diesel, check the EGR cooler recall status immediately -a £500–£1,200 preventative repair is cheaper than the £2,800–£5,000 replacement that follows if ignored.
B48/B38
Cooling System Leaks
Affected models:
F40 116i, 118i, 120i, 128ti, M135i xDrive (all petrol variants).
Typical failure mileage:
60,000–120,000 miles.
Root cause:
The cooling system on B38 and B48 engines -including the expansion tank, water pump, and plastic fittings -can develop leaks over time. Coolant loss can lead to overheating and, if ignored, engine damage.
Tiered Cost Table
Preventative (Repair)
Dealer
Specialist
£500–£1,200
£300–£800
Water pump, expansion tank, coolant pipes
Catastrophic (Replacement)
Dealer
Specialist
£4,000–£7,000
£2,800–£6,500
Full reconditioned engine
Our Recommendation
On any F40 petrol approaching 60,000 miles, have the cooling system inspected -a £300–£800 preventative repair is cheaper than the £2,800–£6,500 replacement that follows if ignored.
B47
Diesel DPF Clogging (Urban Use)
Affected models:
F40 116d, 118d, 120d, 125d (all diesel variants).
Typical failure mileage:
60,000–120,000 miles.
Root cause:
Diesel particulate filters clog with soot when the car is used predominantly for short urban journeys that don't allow the DPF to regenerate. Warning lights and reduced power are the symptoms; ignored, it can require DPF replacement or engine damage.
Tiered Cost Table
Preventative (Repair)
Dealer
Specialist
£500–£1,000
£300–£800
Forced DPF regeneration, injector clean
Catastrophic (Replacement)
Dealer
Specialist
£1,000–£2,000 (DPF) / £4,000–£6,000 (engine)
£800–£1,500 (DPF) / £2,800–£5,000 (engine)
DPF replacement or full engine replacement
Our Recommendation
On any F40 diesel used predominantly in urban environments, ensure regular motorway runs to allow DPF regeneration -a £300–£800 preventative service is cheaper than the £800–£1,500 DPF replacement that follows if ignored.
VariantEngine Code
Used (Supply)
Reconditioned (Supply)
Rebuilt (Supply)
Labour HoursScope note: All variants listed are F40 1 Series only. The F40 marked BMW's switch to front-wheel drive -the M135i xDrive uses BMW's xDrive all-wheel-drive system to deliver 306 bhp. The 128ti is a front-wheel-drive hot hatch positioned between the 120i and M135i. The 225xe is the plug-in hybrid variant.
Most Requested Engines (2025)
Most Requested Variants
Average Replacement Cost
£2,800–£6,500 supply-only
[BMW-QUOTE]
Most Common Failures
Live FeedBMW 1 Series 120d
B47D20A
BirminghamEGR cooler coolant leak5
enquiries
Updated MonthlyBMW 1 Series 118i
B38A15
LondonWater pump failure4
enquiries
Updated MonthlyBMW 1 Series M135i xDrive
B48A20
ManchesterCoolant loss, overheating3
enquiries
Updated MonthlyMost Requested Engines (2025)
Most Requested Variants
Average Replacement Cost
£2,800–£6,500 supply-only
[BMW-QUOTE]
Most Common Failures
Most Requested Engines (2025)
Most Requested Variants
Average Replacement Cost
£2,800–£6,500 supply-only
[BMW-QUOTE]
Most Common Failures
Scope note: All variants listed are F40 1 Series only. The F40 marked BMW's switch to front-wheel drive -the M135i xDrive uses BMW's xDrive all-wheel-drive system to deliver 306 bhp. The 128ti is a front-wheel-drive hot hatch positioned between the 120i and M135i. The 225xe is the plug-in hybrid variant.
Most Requested Engines (2025)
Most Requested Variants
Average Replacement Cost
£2,800–£6,500 supply-only
[BMW-QUOTE]
Most Common Failures
Most Requested Engines (2025)
Most Requested Variants
Average Replacement Cost
£2,800–£6,500 supply-only
[BMW-QUOTE]
Most Common Failures
Most Requested Engines (2025)
Most Requested Variants
Average Replacement Cost
£2,800–£6,500 supply-only
[BMW-QUOTE]
Most Common Failures
Live FeedBMW 1 Series 120d
B47D20A
BirminghamEGR cooler coolant leak5
enquiries
BMW 1 Series 118i
B38A15
LondonWater pump failure4
enquiries
BMW 1 Series M135i xDrive
B48A20
ManchesterCoolant loss, overheating3
enquiries
Updated MonthlyTrusted F40 Engine Suppliers
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UK Engine Replacement Services for F40
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