BMW 1 Series F20 Engines -The Complete UK Guide
Every engine fitted to the F20 1 Series -from the 1.6-litre N13 turbo petrol to the 3.0-litre B58 straight-six in the M140i. Real UK costs and honest reliability data for the last rear-wheel-drive 1 Series hatchback. Backed by 344+ real UK F20 enquiries in 2025 [BMW-VERIFIED].
Explore F20 Engines
BMW 1 Series F20 Engine Codes -The Complete Database
Every engine fitted to the F20/F21 1 Series -spanning three engine generations (N13, N20, N47, N55, B38, B37, B47, B48, B58) across petrol, diesel and six-cylinder variants.
Overview
BMW 1 Series F20 -Overview
The F20 is the second generation of the BMW 1 Series, launched in September 2011 as the successor to the E87.
It introduced a longer wheelbase (+30mm), wider track (+51mm front, +72mm rear), and improved interior space while retaining rear-wheel drive -a layout that set it apart from front-driven hatchback competitors. The engine line-up was all-turbocharged from launch, initially featuring 1.6-litre four-cylinder petrols (N13) and 2.0-litre four-cylinder diesels (N47). A significant February 2015 facelift (LCI) brought new engine families -the B38 three-cylinder, B48 four-cylinder and B58 six-cylinder -replacing the older N13, N20 and N47 units. The range-topper evolved from the N55-powered M135i to the B58-powered M140i in 2016.
Key Facts
Platform
BMW L7 (rear-wheel drive)
Predecessor
E87 1 Series
Successor
F40 1 Series (front-wheel drive)
Sibling body styles in this generation
F21 (3-door hatchback)
Market Intelligence
The F20 1 Series generated 344 real UK engine enquiries in 2025 [BMW-VERIFIED], concentrated on the diesel variants (116d, 118d, 120d) as the range reaches affordable used-car territory.
Best & Worst Engines
Best Petrol Overall
B58B30 (M140i, 340 bhp)
“BMW's B58 straight-six is a masterpiece -smooth, responsive, and robust. The M140i is the last of the rear-drive 1 Series hot hatches, and this engine is the highlight. Fewer known issues than the N55 it replaced, and a stronger bottom end.”
Who it's for: enthusiasts who want the ultimate F20 experience.
Best Diesel Overall
B47D20A (post-LCI 116d/118d/120d, 116–190 bhp)
“The B47 is a significant improvement over the N47 -timing chain issues are far less frequent, and the engine is smoother and more refined. The 120d (190 bhp) offers the best blend of performance and economy.”
Who it's for: buyers who want diesel economy without the N47's timing chain anxiety.
Highest Risk
N47D20C/D (pre-LCI 116d/118d/120d/125d)
“The N47 diesel family carries the infamous rear-mounted timing chain risk -cold-start rattle is the warning, and a snapped chain means full replacement. The 125d's twin-turbo setup adds further complexity.”
Who it's for: buyers on a budget who are willing to accept the chain risk.
Most Expensive Failure
N55B30 (M135i, 320–326 bhp)
“The N55 is a great engine, but it's the most expensive to replace in the F20 range -HPFP, VANOS and turbo issues can add up quickly. The B58 that replaced it is more robust.”
Who it's for: M135i buyers with deep pockets and full service history.
Best Value
B48B20 (post-LCI 120i/125i, 184–224 bhp)
“The 2.0-litre B48 petrol is the sweet spot -more reliable than the N13 it replaced, with strong performance and reasonable running costs. The 125i (224 bhp) offers near-M135i performance without the six-cylinder running costs.”
Who it's for: buyers who want petrol performance without the M135i's premium.
Most Overlooked
B38B15 (post-LCI 116i/118i, 109–136 bhp)
“The 1.5-litre three-cylinder B38 is often dismissed as 'the entry-level engine' -but it's a gem. Smooth, characterful, and significantly more reliable than the N13 it replaced. The 118i (136 bhp) is surprisingly punchy and returns excellent fuel economy.”
Who it's for: buyers who prioritise running costs and don't need six-cylinder power.
BMW 1 Series F20 -Ownership Economics
The F20 rule
A £3,200–£6,000 N47 recon against a £3,000–£12,000 F20 sits at 27–200% of the car's value【EM-VERIFIED】. On a sub-£4,000 example, that brushes our 70% BMW scrap threshold -we'll honestly tell you to walk away. Against a well-kept £8,000+ example, the same recon drops to 40–75% -a repair decision, not a financial one. Value the car first. For B58 M140i cars, the high retained value (£10,000–£18,000+) means replacement is almost always viable.
Key Takeaways
Which F20 Costs Least To Own?
B38 116i/118i -simple three-cylinder, fewer failure modes, cheap parts.
Which F20 Costs Most To Own?
N55 M135i -HPFP and VANOS repairs add up fast.
Which F20 Is Best Value?
B47 120d (post-LCI) -strong performance, excellent economy, and none of the N47's timing chain anxiety.
Common Problems
F20 Engine Replacement Costs -By Engine and Condition
No Generation variance from the EM_Proprietary_Data baseline figures -F20 1 Series shares the L7 platform with other BMW models, with similar engine-bay access, so costs are inherited directly per the Authority Model, with no divergence note required.
Core Variants
Diesel & Petrol Lineup
Scope note: All variants listed are F20 (5-door) and F21 (3-door) 1 Series. The 116d EfficientDynamics Edition (2012–2015) used a 1.6-litre N47 diesel rather than the 2.0-litre. M135i (2012–2016) used the N55 six-cylinder; M140i (2016–2019) used the B58 six-cylinder. Post-LCI (2015–2019) models switched from N13/N20/N47 to B38/B48/B47/B58 engines.
Market Intelligence
Most Requested E90 Engines (2025)
- 1.1. N47D20 (largest share of diesel enquiries)
- 2.2. B47D20
- 3.3. B58B30 (M140i)
Most Requested E90 Variants
- 1.1. 120d
- 2.2. 118d
- 3.3. M140i
Average E90 Replacement Cost
£4,200 reconditioned, supply only [BMW-QUOTE]
Most Common E90 Failures
- 1.1. N47 timing chain stretch
- 2.2. N13 timing chain/VANOS
- 3.3. B38/B48/B58 cooling system leaks
BMW 1 Series
F20 118d
5
enquiries
BMW 1 Series
F20 M140i
3
enquiries
BMW 1 Series
F20 120i
3
enquiries
FAQ
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