BMW 5 Series 520i Engine ReplacementCompare Prices & Get Quotes
Get quotes today from trusted UK BMW 5 Series 520i engine specialists. Compare prices on reconditioned, rebuilt and used 2.0-litre turbo petrol engines for the E60, F10 and G30 520i - supply & fit available nationwide.
Supply & Fit Available
12-Month Warranty
Nationwide Delivery
100+ Suppliers
From £1,500 to £3,600
Used from £1,200 · Reconditioned from £1,800 · Common codes: N46B20, N20B20, B48B20
From £1,200
Tested, bare/short engine
From £1,800
Rod bearings addressed, tested
From quote
Upgraded bearings, full teardown, revised valvetrain
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3 Simple Steps3 Simple Stepsto Finding the Best BMW 5 Series 520i Replacement Engineto Finding the Best BMW 5 Series 520i Replacement Engine
Most replacements completed within 3-5 days.
Variant HistoryBMW 5 Series 520i - Engine History & Specs at a Glance
The BMW 5 Series 520i has been the entry-level petrol variant across three generations of the executive saloon. From the naturally aspirated N46B20 in the E60, through the turbocharged N20B20 in the F10, to the modern B48B20 in the G30, the 520i badge has consistently delivered accessible four-cylinder petrol power with BMW's signature rear-wheel-drive dynamics and executive refinement.
Variant HistoryBMW 5 Series 520i - Engine History & Specs at a Glance
The BMW 5 Series 520i has been the entry-level petrol variant across three generations of the executive saloon. From the naturally aspirated N46B20 in the E60, through the turbocharged N20B20 in the F10, to the modern B48B20 in the G30, the 520i badge has consistently delivered accessible four-cylinder petrol power with BMW's signature rear-wheel-drive dynamics and executive refinement.
BMW 5 Series 520i
Fuel TypePetrol (naturally aspirated to 2007, turbocharged from 2010, MHEV from 2020)
Engine Size2.0L (1,995-1,998cc)
Power Output Range150-184hp across the variant's historyEngine History Timeline
E60 520i launched with N46B20 2.0-litre naturally aspirated four-cylinder 150-170hp, Valvetronic
E60 LCI updates N46B20 with minor ECU calibration changes
F10 520i debuts with N20B20 2.0-litre turbocharged four-cylinder 184hp, TwinPower Turbo
F10 LCI continues with N20B20; B48B20 introduced in G30 520i 184hp, closed-deck block
G30 LCI updates B48B20 with 48V mild hybrid 184hp, improved efficiency
G60 520i launched with B48B20 208hp, 48V mild hybrid
Key Specs Snapshot
Fuel TypePetrol (naturally aspirated to 2007, turbocharged from 2010, MHEV from 2020)Engine Size2.0L (1,995-1,998cc)Power Output Range150-184hp across the variant's historyYears Produced2003-presentEvery engine fitted to the BMW 5 Series 520i is covered below, with UK rebuilt pricing and known failure points specific to each 2.0-litre petrol generation.
BMW 5 Series 520i Engine Codes - Specifications & Replacement CostBMW 5 Series 520i Engine Codes - Specifications & Replacement Cost
2.0L Naturally Aspirated Petrol (2003-2010)
Power Output150-170hp (110-125kW) @ 6,200rpmTorque200-210Nm @ 3,600rpmDisplacement1,995ccYears Fitted2003-2010 (E60 520i)Engine FeaturesNaturally aspirated inline-four, Valvetronic, DOHC 16-valve, aluminium block
Compatible Trim Levels
- 520i
- 520i SE
- 520i Sport
- 520i M Sport
Find your exact engine code, specs and UK replacement cost guide.
Used
Tested, ready-to-fit engine
£800-£1,400
Reconditioned
Addressed known issues, tested
£1,400-£2,200
Rebuilt
Full teardown, upgraded internals
£1,800-£2,800
Common Failure
Timing chain tensioner wear causing rattling on cold start, valve cover and oil filter housing gasket leaks, VANOS solenoid failure, cooling system degradation.
The BMW 5 Series 520i has evolved from the naturally aspirated N46 to the turbocharged N20 and the modern B48, each with its own well-documented wear patterns. The N20 engine family drives the highest volume of replacement enquiries due to early timing chain guide degradation, while the B48 suffers from cooling system weaknesses. Every rebuilt engine supplied through EnginesMarket includes upgraded components designed to address these original failure points - plus a minimum 12-month unlimited mileage warranty.
Why the F10 520i N20 Engine Rattles on Start-Up
Affected Vehicles
BMW 5 Series 520i (F10 2010-2016, N20B20)
Typical Failure Mileage
40,000-70,000 miles
Root Cause
The N20's plastic timing chain guides degrade under heat cycling, leading to chain slack, rattling on cold start, and eventual chain slip or snap. If ignored, the chain can skip teeth, allowing pistons to contact valves - catastrophic engine failure requiring full replacement.
Why It Happens
The N20's plastic timing chain guides degrade under heat cycling, leading to chain slack, rattling on cold start, and eventual chain slip or snap. If ignored, the chain can skip teeth, allowing pistons to contact valves - catastrophic engine failure requiring full replacement.
Dealer (parts + labour)
£2,500-£3,500
Specialist (parts + labour)
£1,400-£1,900
What it involves
Replace timing chain, guides, tensioner, oil pump sprocket
Suitability
Viable if caught early before chain jumps; 60,000+ mile lifespan
1 - 2 daysDealer (parts + labour)
£4,500-£6,500
Specialist (parts + labour)
£2,200-£3,400
What it involves
Supply & fit rebuilt N20B20 with reinforced chain guides, upgraded tensioner, 12-month warranty
Suitability
Required if chain has snapped causing valve/piston damage
1 - 2 daysAll prices are indicative UK market ranges based on current UK specialist supplier data.| Repair Tier | Dealer (Parts + Labour) | Specialist (Parts + Labour) | What It Involves | Suitability | Estimated Time |
|---|---|---|---|---|---|
 Preventative - Timing Chain & Tensioner Kit Minor | £2,500-£3,500 | £1,400-£1,900 | Replace timing chain, guides, tensioner, oil pump sprocket | Viable if caught early before chain jumps; 60,000+ mile lifespan | 1 - 2 days |
 Full Replacement - rebuilt/reconditioned engine Best Value | £4,500-£6,500 | £2,200-£3,400 | Supply & fit rebuilt N20B20 with reinforced chain guides, upgraded tensioner, 12-month warranty | Required if chain has snapped causing valve/piston damage | 1 - 2 days |
Vehicle Value Check
Vehicle Value Check
A typical BMW 5 Series 520i is worth £4,000-£18,000 depending on generation, mileage, and condition (`[THIRD-PARTY]` - Auto Trader market observation). For an F10 520i worth £4,000-£8,000, a rebuilt engine at £2,200-£3,400 can represent 40-70% of the vehicle's value - evaluate body, gearbox, and interior condition carefully before committing. For G30 examples worth £10,000+, replacement is generally viable.
Our Recommendation
Our Recommendation
If your F10 520i develops a cold-start rattle that disappears as the engine warms, act immediately - preventative chain replacement saves thousands. Once the chain snaps, the engine is beyond economic repair. Frequent oil changes (every 8,000-10,000 miles) are critical for N20 longevity.
Don't Let Engine Failure Write Off Your BMW 5 Series 520i
A failed N46, N20 or B48 doesn't have to mean the end of the road for your 520i. Whether you're facing timing chain guide failure on the N20, cooling system issues on the B48, or oil leaks on any generation, EnginesMarket connects you with trusted UK BMW petrol specialists who supply rebuilt engines with upgraded components specifically designed to address the original failure points. Every engine comes with a minimum 12-month unlimited mileage warranty, nationwide delivery, and supply & fit options across the UK. Compare prices today - and get back on the road without paying the main dealer premium.
Compare rebuilt N20B20 engine prices for your BMW 5 Series 520i
12-Month Minimum
UK Specialists Vetted
Best Price GuidanceImportant Information
Important Information
"All prices are indicative UK market ranges based on historical quote data and repair requests from our network of engine specialists. Dealer pricing is estimated based on published main dealer labour rates and genuine OEM parts pricing. Specialist pricing reflects actual quote data from EnginesMarket's UK network. Actual costs vary depending on damage severity, vehicle condition, variant, and workshop location within the UK. Use our free comparison tool to get tailored quotes for your specific BMW 5 Series 520i. Every engine supplied through EnginesMarket carries a minimum 12-month unlimited mileage warranty - always confirm exact terms with your chosen supplier."
BMW 5 Series 520i Engine ReplacementFrequently Asked Questions
Question 1How much does a BMW 5 Series 520i engine replacement cost in the UK-
A BMW 5 Series 520i engine replacement typically costs £1,500-£3,600 supply-only for rebuilt units, or £2,800-£5,500 fitted by a specialist. Prices vary by engine code and generation.
- Used N46B20 engines: £800-£1,400 supply-only
- Used N20B20 engines: £1,200-£1,900 supply-only
- Reconditioned B48B20 units: £2,200-£3,200 supply-only
- Rebuilt N20B20 units: £2,200-£3,400 supply-only
- Professional fitting adds £800-£1,500 depending on workshop location
Question 2Which engine does the BMW 5 Series 520i have - N46, N20 or B48-
The 520i badge spans three engine families depending on the generation:
- E60 520i (2003-2010): N46B20, 150-170hp, naturally aspirated
- F10 520i (2010-2016): N20B20, 184hp, turbocharged
- G30 520i (2017-present): B48B20, 184hp, turbocharged, closed-deck block
- G60 520i (2023-present): B48B20, 208hp, 48V mild hybrid
Question 3Is the BMW 5 Series 520i N20 engine reliable- I've heard about timing chain problems.
The N20B20 is a capable engine, but early units (pre-2015) are prone to timing chain guide degradation between 40,000-70,000 miles. The problem is caused by plastic guides that become brittle under heat cycling.
- Timing chain rattle on cold start is the first warning sign
- Preventative chain replacement costs £1,400-£1,900 at a specialist
- Post-2015 N20 units received revised guide materials
- B48 engines in G30 models have largely resolved timing chain concerns
Question 4What are the signs of cooling system failure on a BMW 5 Series 520i B48-
The B48 engine's most common cooling system issues include:
- Coolant level drops without visible external leaks
- Coolant vent line cracking (between cylinder head and expansion tank)
- Oil filter housing cracking causing coolant loss
- Warning lights on the dashboard
- Overheating if coolant loss is ignored
Question 5Is it worth replacing the engine on a high-mileage BMW 5 Series 520i-
For an F10 520i worth £4,000-£8,000, a rebuilt N20 at £2,200-£3,400 can make financial sense if the body, gearbox, and interior are in good condition. For G30 examples, replacement is generally viable given higher retained values.
- Compare replacement cost against vehicle value - replacement is viable up to 70% of car's value
- F10 520i values have stabilised; a good example justifies investment
- B48 engines in G30 command higher value - replacement more easily justified
- Always factor 12-month warranty into replacement decision
Question 6Can I replace my N20 engine with a B48 in my BMW 5 Series 520i-
While both are 2.0-litre turbo petrol engines, swapping an N20 for a B48 is not straightforward and is rarely cost-effective:
- Different engine mounts, wiring harness, and ECU calibration
- B48 requires different cooling system components
- DME coding and immobiliser adaptation required
- Specialist verification essential before ordering
Why Choose UsCompare BMW 5 Series 520iEngine PricesToday
11,000+ BMW 5 Series engines supplied through our network, including 520i variants
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Comparing quotes for your BMW 5 Series 520i is free, no-obligation, and specific to your exact executive saloon and its engine code - N46B20, N20B20, or B48B20. Whether you need a used replacement, a reconditioned unit, or a full rebuilt engine with upgraded components, our network of trusted UK BMW petrol specialists delivers transparent pricing and nationwide coverage. Don't let a failed engine end the life of the UK's favourite executive saloon - compare prices today and get back on the road with confidence.
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