BMW 3 Series F31 Engines -The Complete UK Guide
Every engine fitted to the F31 Touring – from the 1.6-litre N13 four-cylinder to the 3.0-litre N57 six-cylinder diesel and the B58 that replaced the N55. Real UK replacement costs, honest reliability data, and the timing chain concerns that defined the N20 and N47 era. Backed by real UK F31 enquiries in 2025 [BMW-VERIFIED].
Explore F31 Engines
BMW 3 Series F31 Engine Codes -The Complete Database
Every engine fitted to the F31 Touring – from the entry-level four-cylinder to the range-topping six-cylinder diesel.
Overview
BMW 3 Series F31 -Overview
The BMW F31, launched in 2012 as the Touring (estate) version of the sixth-generation 3 Series, combines the practicality of a load-lugging estate with the dynamic prowess expected of a BMW.
Built on the same platform as the F30 saloon, the F31 features a 40:60 front-to-rear weight distribution and a range of turbocharged four- and six-cylinder engines. A 2015 facelift brought B-series engines and updated technology, while the range-topping 335d xDrive offered 313 hp and all-wheel-drive traction.
Key Facts
Platform
BMW L7 (F30/F31/F34)
Predecessor
BMW 3 Series E91
Successor
BMW 3 Series G21
Sibling body styles in this generation
F30 (saloon), F34 (Gran Turismo)
Market Intelligence
The F31 generated real UK engine enquiries in 2025 [BMW-VERIFIED], with the N47/B47 diesel and N20/B48 petrol accounting for the majority of demand as these cars enter their second and third ownership cycles.
Best & Worst Engines
Best Diesel Overall
B47D20A (post-2015, LCI) – "The B47 is a significant improvement over the N47 – timing chain issues are less prevalent, and the EGR cooler recall has addressed a known weakness. It's smoother, cleaner and more reliable than its predecessor."
“”
Who it's for: buyers who want diesel economy without the N47's timing chain anxiety.
Best Petrol Overall
B58B30A (340i, post-2015) – "The B58 straight-six is BMW's finest modern engine – 326 hp of silky-smooth power with none of the N55's earlier weaknesses. Water pump and cooling system are the only real demands; this engine is widely considered bulletproof."
“”
Who it's for: buyers who want effortless six-cylinder power with modern reliability.
Highest Risk
N20B20 (320i/328i, pre-2015) – "The N20 four-cylinder carries a significant timing chain guide weakness – failure can occur as early as 60,000 miles, leading to a £4,000+ engine replacement. Cold-start rattle is the warning sign."
“”
Who it's for: only buyers who have confirmed chain guide replacement or are budgeting for it.
Most Expensive Failure
N57D30B (335d xDrive) – "The triple-turbo diesel is a complex piece of engineering – turbocharger failure and EGR cooler issues can lead to bills exceeding £5,000. The all-wheel-drive system adds further complexity."
“”
Who it's for: buyers who want diesel performance and accept the associated running costs.
Best Value
B48B20A (320i, post-2015) – "The B48 four-cylinder delivers 184 hp with none of the N20's timing chain anxiety. It's smoother, more efficient and more reliable than its predecessor – the sweet spot of the F31 petrol range."
“”
Who it's for: buyers who want modern four-cylinder reliability without the N20 gamble.
Most Overlooked
B38B15 (318i, post-2015) – "The 1.5-litre three-cylinder is often dismissed as underpowered, but it delivers 136 hp with excellent economy and a characterful exhaust note. It's the cheapest F31 to run and maintain."
“”
Who it's for: buyers who want F31 estate practicality with minimal running costs.
BMW 3 Series F31 -Ownership Economics
The F31 rule
A £2,800–£5,000 N47/B47 recon against a £6,000–£15,000 F31 sits at 19–83% of the car's value. On a sub-£8,000 diesel F31, that brushes our 70% BMW threshold – we'll honestly tell you to walk away unless the car has documented chain work. Against a £12,000+ low-mileage example, the same recon drops to a routine 23–42% – a repair decision, not a financial one. The B58 replacement at £7,000 is well within the value of a £20,000 340i.
Key Takeaways
Which F31 Costs Least To Own?
B38B15 (318i) – cheapest entry, lowest insurance, simple three-cylinder.
Which F31 Costs Most To Own?
N57D30B (335d) – triple-turbo complexity and premium running costs.
Which F31 Is Best Value?
B48B20 (320i/330i) – the sweet spot between performance and running costs.
Common Problems
F31 Engine Replacement Costs -By Engine and Condition
Core Variants
Diesel & Petrol Lineup
Scope note: All variants listed are F31 only. The F30 saloon and F34 Gran Turismo share most of these engines but are covered on their own Generation Pages, since body style affects boot space and weight rather than engine fitment. The 335d xDrive was the only diesel offered with all-wheel drive in the F31 range.
Market Intelligence
Most Requested E90 Engines (2025)
- 1.1. N47D20C / B47D20A (320d) – diesel enquiries dominate
- 2.2. N57D30A (330d) – six-cylinder diesel
- 3.3. B48B20B (330i) – post-LCI petrol enquiries [PATTERN DATA].
Most Requested E90 Variants
- 1.1. 320d
- 2.2. 330d
- 3.3. 330i [PATTERN DATA].
Average E90 Replacement Cost
£1,500–£8,000 supply only [BMW-QUOTE].
Most Common E90 Failures
- 1.1. N20 timing chain guides
- 2.2. N47 timing chain stretch
- 3.3. EGR cooler failure (diesel)
- 4.4. B-series water pump wear [PATTERN DATA].
BMW 320d
F31 (N47D20C)
6
enquiries
BMW 330d
F31 (N57D30A)
4
enquiries
BMW 330i
F31 (B48B20B)
3
enquiries
FAQ
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