
BMW 1 Series F40 Engines -The Complete UK Guide
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].
Explore F40 EnginesBMW 1 Series F40 Engine Codes -The Complete 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
BMW 1 Series F40 -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
Platform
FAAR (front-wheel-drive architecture, shared with Mini)
Predecessor
BMW 1 Series F20/F21 (2011–2019)
Successor
Current model -on sale
Sibling body styles
None -F40 is sole 1 Series hatchback body style
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).
Best & 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.
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Who it's for: buyers who prioritise running costs over outright performance.

BMW 1 Series F40 -Ownership Economics
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.
Common Problems

F40 Engine Replacement Costs -By Engine and Condition
Core Variants
Diesel & Petrol Lineup
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.
Market Intelligence
Most Requested E90 Engines (2025)
- 1.1. B47D20A 2.0 Diesel (930 B47-wide enquiries)
- 2.2. B48A20 2.0 Petrol (344 1 Series-wide)
- 3.3. B38A15 1.5 Petrol (344 1 Series-wide)
Most Requested E90 Variants
- 1.1. 120d (2.0 diesel)
- 2.2. 118i (1.5 petrol)
- 3.3. M135i xDrive (2.0 high-output petrol)
Average E90 Replacement Cost
£2,800–£6,500 supply-only [BMW-QUOTE]
Most Common E90 Failures
- 1.1. B47 diesel EGR cooler failure
- 2.2. B48/B38 cooling system leaks
- 3.3. B47 diesel DPF clogging (urban use)

BMW 1 Series 120d (B47D20A)
5
enquiries

BMW 1 Series 118i (B38A15)
4
enquiries

BMW 1 Series M135i xDrive (B48A20)
3
enquiries
FAQ

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