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1.5 EcoBoost vs 1.4 and 1.6 16v: which engine is more reliable?

According to our risk index, the 1.5 EcoBoost carries less risk than the 1.4 and 1.6 16v: 43/100 versus 45/100 (both moderate risk). The 1.5 EcoBoost has 2 documented serious faults, the main one being «Coolant loss through a microcrack in the engine block (4-cylinder 1.5)»; the 1.4 and 1.6 16v has 1 documented serious fault, the main one being «Timing belt breakage or premature failure».

Risk index

1.5 EcoBoost

43

Moderate risk · 2 serious faults

Lower risk

Risk index

1.4 and 1.6 16v

45

Moderate risk · 1 serious fault

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

24 sourcesHow we work

Is the 1.5 EcoBoost reliable?

These are two engines with the same name. The four-cylinder (2014-2019: Mondeo, Focus, Kuga, C-Max) has documented cases of coolant loss through a microcrack in the block, which can end in a new engine. The three-cylinder Dragon (from 2018) has hardly any mechanical faults cited, but the Kuga has been recalled several times because an injector can crack and cause a fuel leak with a fire risk.[1][2][3][4]

See the 2 of the 1.5 EcoBoost 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 1.5 EcoBoost and 1.4 and 1.6 16v
1.5 EcoBoost1.4 and 1.6 16v
Technical data
TypeEngineEngine
FuelPetrolPetrol
Displacement1,498 cm³—
TimingChainTiming belt (dry)
Power120–200 hp75–135 hp
Productionsince 2014[9][10][11][12][13]since 1998[14][15][16]
Reliability
Risk index (what is it?)43Moderate risk45Moderate risk
Documented faults26
Of high or critical severity21
Worst severityCritical severityHigh severity
Main faults
  1. Critical severity: Coolant loss through a microcrack in the engine block (4-cylinder 1.5)
  2. Critical severity: Fuel leak from cracked injectors, with a fire risk (Kuga Dragon)
  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][17]
With cautionVersions to be cautious about
  • 1.5 EcoBoost 4-cylinder 120/150/160/182 hp (Mondeo, Focus, Kuga, C-Max, S-Max, Galaxy, 2014-2019)[1][2]
  • 1.5 EcoBoost Dragon 3-cylinder 120/150/182 hp (Kuga III and Focus IV, from 2018)[3][4][18][19]
  • 1.5 EcoBoost ST 200 hp (Fiesta ST 2018-2023 and Puma ST, code YZJA)[3][11][20]
  • 1.4 16V 75-100 hp (K4J, 1999-2012)[21][22]
  • 1.6 16V 110-135 hp with variable valve timing unit (K4M, 1998-2020)[7][23][24]
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

1.5 EcoBoost

See the 10 models with the 1.5 EcoBoost

1.4 and 1.6 16v

See the 13 models with the 1.4 and 1.6 16v

Other comparisons

With the 1.5 EcoBoost

With the 1.4 and 1.6 16v

Compare other engines

That is the comparison you are viewing: change one of the two engines.

Sources

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

  1. Ford Mondeo V - Auto ReviewANWB · Consumer association · published 2 September 2024 · consulted 8 October 2026 · in Dutch
  2. Ford EcoBoost Probleme und Haltbarkeitgebrauchtwagenberater.de · Motoring press · consulted 8 October 2026 · in German
  3. Rückruf: Bei diesen Ford-Modellen besteht BrandgefahrADAC · Motoring press · published 2 February 2026 · consulted 8 October 2026 · in German
  4. Rückruf Ford Kuga: Brandgefahr wegen defekter Einspritzventileauto motor und sport · Motoring press · published 3 May 2024 · consulted 8 October 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. Ford EcoBoost engineWikipedia (en) · Other source · consulted 8 October 2026
  10. Ford EcoBoostWikipedia (de) · Other source · consulted 8 October 2026 · in German
  11. Every Ford Powered By The 1.5L EcoBoost 'Dragon'SlashGear · Motoring press · consulted 8 October 2026
  12. Ford Kuga Titanium 1.5 EcoBoost Auto-Start-Stop 150 CV 4x2 (2014-2016): precio y ficha técnicakm77 · Technical documentation · consulted 8 October 2026 · in Spanish
  13. Ford Kuga MK3 2019-2026 Probleme und Schwachstellengebrauchtwagenberater.de · Motoring press · consulted 8 October 2026 · in German
  14. Renault K-Type engineWikipedia (inglés) · Other source · consulted 27 September 2026
  15. Moteur K RenaultWikipedia (francés) · Other source · consulted 27 September 2026 · in French
  16. Anexo:Motores de RenaultWikipedia (español) · Other source · consulted 27 September 2026 · in Spanish
  17. Fiabilité et pannes du Dacia Logan 1Fiches-auto.fr · Motoring press · consulted 27 September 2026 · in French
  18. Trois problèmes avec le Ford Kuga : jauge de carburant, injecteurs et toit panoramique défectueuxcar-recalls.eu · Other source · consulted 8 October 2026 · in French
  19. Tous les problèmes sur Ford FOCUS 4 2018 (93 témoignages)fiches-auto.fr · Owners' forum · consulted 8 October 2026 · in French
  20. YZJA engine (Ford 1.5 EcoBoost)Motorinsel · Technical documentation · consulted 8 October 2026
  21. Fiabilité et pannes de la Renault Clio 2Fiches-auto.fr · Motoring press · consulted 27 September 2026 · in French
  22. Fiabilité et pannes de la Renault Clio 3Fiches-auto.fr · Motoring press · consulted 27 September 2026 · in French
  23. Fiabilité et pannes de la Renault Mégane 2Fiches-auto.fr · Motoring press · consulted 27 September 2026 · in French
  24. Fiabilité et pannes du Renault Scénic 2Fiches-auto.fr · Motoring press · consulted 27 September 2026 · in French