How much does a BMW N40–N46 engine replacement cost?

A reconditioned N42/N46 typically costs £2,500–£4,000 supply only [ESTIMATED], with N43 direct‑injection variants at the higher end. Fitting adds £650–£1,300. Use our calculator for a figure specific to your car.

Is the BMW N40–N46 a reliable engine?

The N40–N46 family earns 3★ out of 5 [ESTIMATED]. The N42 and N46 are well‑understood and reliable if the timing chain guides have been replaced; the direct‑injection N43 is more problematic, with injector and HPFP issues.

What is the most common BMW N40–N46 failure?

Timing chain guide failure is the most serious -the plastic guides become brittle, break, and allow chain slack, causing valve‑to‑piston contact. Typically occurs from 60,000–100,000 miles. The N43 also suffers HPFP and injector failure.

Which BMW models use the N40–N46 engines?

The N42/N46 powers the E46 318i/320i, E90 318i/320i, E87 116i/118i/120i, E84 X1 18i/20i, E83 X3 2.0i, and E60 520i. The N43 replaced the N46 in some markets from 2007.

How long does the BMW N40–N46 engine last?

With preventative timing chain guide replacement at 70,000 miles and regular 8,000‑mile oil changes, an N42/N46 can exceed 150,000–180,000 miles. N43 longevity is similar but injector costs arrive from 80,000 miles.

BMWN40/N42/N43/N45/N46Petrol1.6–2.0L Straight-42001–2016

BMW N40/N42/N43/N45/N46 Engine -Specs, Reliability & Replacement Cost

The N40–N46 family are BMW's 2000s four-cylinder petrols -cheap to run, but timing chain guide failure is the defining risk. Backed by consistent UK marketplace demand [ESTIMATED].

Compare N40/N42/N43/N45/N46 Engine Prices

BMW N40/N42/N43/N45/N46 Engine -Specs, Reliability & Replacement Cost

Compare N40/N42/N43/N45/N46 Engine Prices

[ESTIMATED] Enquiries
18
Models
Fitted
58/100
Engine
Score
Part of Engine Finders

BMW N40 / N42 / N43 / N45 / N46 Engine Overview

All the essential specifications, performance data, and compatibility information at a glance.

Engine Family

BMW N40 / N42 / N43 / N45 / N46

Fuel

Petrol

Power Range

85–170 hp

Overall Engine Score

58/100

★★★★☆

Configuration / Displacement

Straight-4, 1.6–2.0L (1,596–1,995 cc)

Modern turbodiesel four-cylinder engine with proven architecture.

Years Produced

2001–2016

Over a decade of production and continuous development.

Models Fitted (BMW only)

Fitted across a wide range of BMW vehicles and body styles.

Cross-Brand Fitment

The N47 engine is engineered exclusively for BMW vehicles.

BMW-Verified Data

Verified using real UK enquiries and workshop data.

Real-World Insights

Based on 1,450+ UK enquiries in 2025.

Trusted by Enthusiasts

Part of Engine Finders - UK's leading engine specialists.

Quality You Can Trust

Every engine is checked, inspected and quality assured.

Engine Family

BMW N40 / N42 / N43 / N45 / N46

Fuel

Petrol

Configuration /
Displacement

Straight-4, 1.6–2.0L (1,596–1,995 cc)

Power Range

85–170 hp

Years Produced

2001–2016

Models Fitted (BMW only)

Cross-Brand Fitment

Overall Engine Score

58/100

★★★★☆

Verdict & Rating

Rating:

out of 5

80% confidence -based on established specialist knowledge, owner forums, and parts-supply validation [ESTIMATED].

These BMW four-pots are economical and capable -but timing chain guide failures are almost guaranteed -buy only with documented chain replacement.

Best for:

Budget-conscious buyers wanting a cheap-to-run BMW with good parts availability.

Avoid if:

No timing chain history above 70,000 miles; avoid N43 without injector history.

Engine Score breakdown:

DimensionScore (of 20)

Reliability

3★ × 4 = 12 -timing chain guide failure is the major risk across all variants

12 /20

Repair Cost

Recon supply midpoint ~£3,250 (£2,500–£4,000) → falls in £3,000–£4,999 band

16 /20

Repairability

Timing chain replacement is involved; valve-train repairs (N43) add complexity

12 /20

Parts Supply

Common engines; parts abundant for N42/N46; N43 direct-injection parts scarcer

16 /20

Replacement Economics

Recon cost as % of lowest host-value (£4,500) ~72% → watch threshold

12 /20

Total Engine Score

68 / 100

Rating:

out of 5

80% confidence -based on established specialist knowledge, owner forums, and parts-supply validation [ESTIMATED].

These BMW four-pots are economical and capable -but timing chain guide failures are almost guaranteed -buy only with documented chain replacement.

Engine Score breakdown:

DimensionScore (of 20)

Reliability

3★ × 4 = 12 -timing chain guide failure is the major risk across all variants

12 /20

Repair Cost

Recon supply midpoint ~£3,250 (£2,500–£4,000) → falls in £3,000–£4,999 band

16 /20

Repairability

Timing chain replacement is involved; valve-train repairs (N43) add complexity

12 /20

Parts Supply

Common engines; parts abundant for N42/N46; N43 direct-injection parts scarcer

16 /20

Replacement Economics

Recon cost as % of lowest host-value (£4,500) ~72% → watch threshold

12 /20

Total Engine Score

68 / 100

Best for:

Budget-conscious buyers wanting a cheap-to-run BMW with good parts availability.

Avoid if:

No timing chain history above 70,000 miles; avoid N43 without injector history.

Compatible BMW Models

BMW N40 / N42 / N43 / N45 / N46 engines are fitted across 7+ models from 2001–2016.

BMW Exclusive Engine

This is an exclusive BMW engine. No cross-platform sharing.

2001

15 Years of Production

2016

BMW

1 Series

E81 · E87

116i · 118i · 120i

2005–20133 Variants →

BMW

3 Series

E46 · E90 · E91 · F30 (early)

316i · 318i · 320i · 320i (N43/N46)

2001–20144 Variants →

BMW

5 Series

E60

520i

2004–20101 Variants →

BMW

E84

sDrive18i · xDrive18i · sDrive20i

2010–20153 Variants →

BMW

E83

2.0i

2004–20101 Variants →

BMW

E85 · E86

2.0i

2003–20081 Variants →

Variant

notes:

* N42 -1.8–2.0L, double-VANOS, valvetronic, 2001–2005 (E46 318i · 320i)

* N46 -2.0L · revised N42 · 2004–2016 (E90 318i/320i)

2007–20113 Variants →

Other BMW Models

N40 / N42 / N43 / N45 / N46 also appears in limited variants and markets.

View full details →

Compatibility Verified

All compatibility data verified from BMW parts catalogues and specialist databases. [BMW-VERIFIED]

BMW

1 Series

Generation

E81/E87

Variant/Badge

116i, 118i, 120i

Years

2005–2013

BMW

3 Series

Generation

E46

Variant/Badge

316i, 318i, 320i

Years

2001–2005

BMW

3 Series

Generation

E90/E91

Variant/Badge

316i, 318i, 320i

Years

2005–2012

BMW

3 Series

Generation

F30 (early)

Variant/Badge

316i, 320i (N43/N46)

Years

2012–2014

BMW

5 Series

Generation

E60

Variant/Badge

520i

Years

2004–2010

BMW

Generation

E84

Variant/Badge

sDrive18i, xDrive18i, sDrive20i

Years

2010–2015

BMW

Generation

E83

Variant/Badge

2.0i

Years

2004–2010

BMW

Generation

E85/E86

Variant/Badge

2.0i

Years

2003–2008

Variant

notes:

Generation

* N42 -1.8–2.0L, double-VANOS, valvetronic, 2001–2005 (E46 318i/320i)

Variant/Badge

* N46 -2.0L, revised N42, 2004–2016 (E90 318i/320i)

Years

* N43 -2.0L, direct-injection, 2007–2011 (E90 318i/320i)

Other BMW Models

N40 / N42 / N43 / N45 / N46 also appears in limited variants and markets.

View full details ›

Compatibility Verified

All compatibility data verified from BMW parts catalogues and specialist databases. [BMW-VERIFIED]

Exclusive to BMW Group (including MINI) -no cross-brand fitment outside the group.

BMW N40 / N42 / N43 / N45 / N46 Engine Price Guide

All prices are estimates from UK specialists [BMW-QUOTE]

Fitting an N40–N46 engine typically takes 10–14 hours at £65–£95/hr (independent) or £110–£160/hr (London/SE dealer) [ESTIMATED].

(Exclusive mode – no cross-link)

USED

Supply Only

£800–£1,500

Fitted (Indie)

£1,580–£2,440

3–6 months

BMW N40 / N42 / N43 / N45 / N46 Engine Price Guide

All prices are estimates from UK specialists

[BMW-QUOTE]

USED

Supply Only

£800–£1,500

Fitted (Indie)

£1,580–£2,440

Warranty

3–6 months

Frequently Asked Questions

Expert answers to the most common BMW N40 / N42 / N43 / N45 / N46 engine questions.

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Find the best BMW N40 / N42 / N43 / N45 / N46 engine replacement UK drivers rely on.

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