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BMW N43/N46 vs 1.4 and 1.6 16v: which engine is more reliable?

According to our risk index, the 1.4 and 1.6 16v carries less risk than the BMW N43/N46: 45/100 (moderate risk) versus 59/100 (high risk). The BMW N43/N46 has 1 documented serious fault, the main one being «Wear and breakage of the timing chain guides»; the 1.4 and 1.6 16v has 1 documented serious fault, the main one being «Timing belt breakage or premature failure».

Risk index

BMW N43/N46

59

High risk · 1 serious fault

Risk index

1.4 and 1.6 16v

45

Moderate risk · 1 serious fault

Lower risk

The index (0–100) weights the severity and frequency of the three most serious documented faults. How it is calculated

19 sourcesHow we work

Is the BMW N43/N46 reliable?

The BMW N43 and N46 (2004-2012) are naturally aspirated four-cylinder engines fitted to the 1 Series E87, 3 Series E90, X1 E84 and Z4 E85/E86, among others. They have a reputation for being solid if properly maintained, but share well-known wear of the timing chain guides and tensioner, of the Valvetronic and of the VANOS valves; the direct-injection N43 adds documented failures of the injectors, ignition coils and the NOx sensor.[1][2][3][4]

See the 4 of the BMW N43/N46 faults

Is the 1.4 and 1.6 16v reliable?

The K4J (1.4) and K4M (1.6), both naturally aspirated 16-valve units, are simple and generally reliable petrol engines: no source consulted documents oil consumption or faults that destroy the block. Their most-cited weak point is the ignition coils, followed by the crankshaft sensor and, on versions with a variable valve timing unit, its pulley; a neglected belt can cause serious damage, as one case in the Renault Laguna II documents.[5][6][7][8]

See the 6 of the 1.4 and 1.6 16v faults

Side-by-side comparison

Comparison of BMW N43/N46 and 1.4 and 1.6 16v
BMW N43/N461.4 and 1.6 16v
Technical data
TypeEngineEngine
FuelPetrolPetrol
Displacement——
TimingChainTiming belt (dry)
Power121–170 hp75–135 hp
Production2004–2012[1][2][9][10]since 1998[11][12][13]
Reliability
Risk index (what is it?)59High risk45Moderate risk
Documented faults46
Of high or critical severity11
Worst severityCritical severityHigh severity
Main faults
  1. Critical severity: Wear and breakage of the timing chain guides
  2. Medium severity: Injector, ignition coil and NOx sensor failures (N43)
  3. Medium severity: Wear of the Valvetronic and the VANOS solenoid valves
  1. Medium severity: Ignition coil failure
  2. High severity: Timing belt breakage or premature failure
  3. Medium severity: Crankshaft position sensor failure
Most expensive documented repairNo reliable dataNo reliable data
Which versions to buy
BuyRecommended versionsNone
  • 1.6 16V 105-110 hp Dacia, without variable valve timing unit (K4M, 2004-2020)[8][14]
With cautionVersions to be cautious about
  • N46B20 127-148 hp, indirect injection (2004-2007)[3][4]
  • N46NB20 150-170 hp, revised ECU (2006-2012)[3][4][15]
  • N43B16 121 hp, 1.6 litres (2007-2011)[1][3]
  • N43B20 121-168 hp, 2.0 litres (2007-2013)[1][3]
  • 1.4 16V 75-100 hp (K4J, 1999-2012)[16][17]
  • 1.6 16V 110-135 hp with variable valve timing unit (K4M, 1998-2020)[7][18][19]
AvoidVersions to avoidNoneNone

Severity of each fault: green, low; amber, medium; red, high; dark red, critical. How we rate them

Cars that each one is fitted to

BMW N43/N46

1.4 and 1.6 16v

See the 13 models with the 1.4 and 1.6 16v

Other comparisons

With the BMW N43/N46

With the 1.4 and 1.6 16v

Compare other engines

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Sources

Every fact on this page links to its source. If you find an error, let us know.

  1. BMW N43Wikipedia (inglés) · Other source · consulted 27 September 2026
  2. BMW N46Wikipedia (inglés) · Other source · consulted 27 September 2026
  3. BMW N43: Bei diesem Benziner ist Ärger vorprogrammiertGebrauchtwagenberater · Motoring press · consulted 27 September 2026 · in German
  4. BMW N46: Typische Probleme & HaltbarkeitGebrauchtwagenberater · Motoring press · consulted 27 September 2026 · in German
  5. Fiabilité et pannes de la Renault Mégane 1Fiches-auto.fr · Motoring press · consulted 27 September 2026 · in French
  6. Fiabilité et pannes du Renault Scénic 1Fiches-auto.fr · Motoring press · consulted 27 September 2026 · in French
  7. Fiabilité et pannes de la Renault Laguna 2Fiches-auto.fr · Motoring press · consulted 27 September 2026 · in French
  8. Fiabilité et pannes du Dacia Duster 1Fiches-auto.fr · Motoring press · consulted 27 September 2026 · in French
  9. BMW N43Wikipedia (alemán) · Other source · consulted 27 September 2026 · in German
  10. BMW N46Wikipedia (alemán) · Other source · consulted 27 September 2026 · in German
  11. Renault K-Type engineWikipedia (inglés) · Other source · consulted 27 September 2026
  12. Moteur K RenaultWikipedia (francés) · Other source · consulted 27 September 2026 · in French
  13. Anexo:Motores de RenaultWikipedia (español) · Other source · consulted 27 September 2026 · in Spanish
  14. Fiabilité et pannes du Dacia Logan 1Fiches-auto.fr · Motoring press · consulted 27 September 2026 · in French
  15. BMW X1 E84 – Bekannte Probleme & SchwachstellenGebrauchtwagenberater · Motoring press · published 9 May 2023 · consulted 27 September 2026 · in German
  16. Fiabilité et pannes de la Renault Clio 2Fiches-auto.fr · Motoring press · consulted 27 September 2026 · in French
  17. Fiabilité et pannes de la Renault Clio 3Fiches-auto.fr · Motoring press · consulted 27 September 2026 · in French
  18. Fiabilité et pannes de la Renault Mégane 2Fiches-auto.fr · Motoring press · consulted 27 September 2026 · in French
  19. Fiabilité et pannes du Renault Scénic 2Fiches-auto.fr · Motoring press · consulted 27 September 2026 · in French