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1.0 EcoBoost vs 1.2 Dualjet and 1.2 VVT: which engine is more reliable?

According to our risk index, the 1.2 Dualjet and 1.2 VVT carries less risk than the 1.0 EcoBoost: 23/100 (low risk) versus 71/100 (high risk). The 1.0 EcoBoost has 3 documented serious faults, the main one being «Degradation of the timing belt running in oil»; the 1.2 Dualjet and 1.2 VVT has no documented serious faults.

Risk index

1.0 EcoBoost

71

High risk · 3 serious faults

Risk index

1.2 Dualjet and 1.2 VVT

23

Low risk · 0 serious faults

Lower risk

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

18 sourcesHow we work

Is the 1.0 EcoBoost reliable?

It is a turbocharged direct-injection three-cylinder that has won Engine of the Year several times, but it has two very well-documented weak points: two belts running in oil (timing and oil pump) that can disintegrate and seize the engine, and cases of coolant leaks and overheating in early units. It is best bought with a service history and the belts checked or replaced on time.[1][2][3][4]

See the 4 of the 1.0 EcoBoost faults

Is the 1.2 Dualjet and 1.2 VVT reliable?

The Suzuki 1.2 VVT and 1.2 Dualjet (K12B/K12C/K12M) is a naturally aspirated petrol engine with a timing chain and indirect injection, fitted since 2008 to the Splash, Swift, Ignis and Baleno, with an SHVS mild-hybrid variant since 2016. It is reliable: there is no serious documented fault with the engine block itself; the main points are a clutch that wears out sooner than expected on some cars and two SHVS recalls that have already been resolved.[5][6][7][8][9]

See the 5 of the 1.2 Dualjet and 1.2 VVT faults

Side-by-side comparison

Comparison of 1.0 EcoBoost and 1.2 Dualjet and 1.2 VVT
1.0 EcoBoost1.2 Dualjet and 1.2 VVT
Technical data
TypeEngineEngine
FuelPetrolPetrol
Displacement999 cm³—
TimingWet belt (belt-in-oil)Chain
Power100–155 hp82–92 hp
Productionsince 2012[1][10][11][12]since 2008[5][6]
Reliability
Risk index (what is it?)71High risk23Low risk
Documented faults45
Of high or critical severity30
Worst severityCritical severityMedium severity
Main faults
  1. Critical severity: Degradation of the timing belt running in oil
  2. Critical severity: Oil pump belt and tensioner failure
  3. Critical severity: Coolant leaks and overheating from the turbo hose
  1. Medium severity: Clutch: premature wear and clutch cable anchor failure
  2. Medium severity: SHVS mild-hybrid system: recalls for the starter generator belt and software
  3. Medium severity: Water pump pulley fixing (2013-2014): recall
Most expensive documented repairup to €1,200Degradation of the timing belt running in oilPublished figure[2]No reliable data
Which versions to buy
BuyRecommended versionsNone
  • 1.2 VVT 86-92 hp (K12B, one injector per cylinder, 2008-2013)[8]
  • 1.2 Dualjet non-hybrid 89-91 hp (K12B/K12C, dual injector, 2013-2020)[9][13][14]
  • 1.2 Dualjet SHVS mild hybrid 82-90 hp (K12C/K12D, since 2016)[9]
With cautionVersions to be cautious about
  • 1.0 EcoBoost 100/125 (Fox, 2012-2017)[2][3][15]
  • 1.0 EcoBoost 100/125/140 with cylinder deactivation (from ~2017)[16][17]
  • 1.0 EcoBoost Hybrid 48V mild hybrid (125/155 hp, from 2019)[1][18]
None
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

1.0 EcoBoost

See the 11 models with the 1.0 EcoBoost

1.2 Dualjet and 1.2 VVT

See the 7 models with the 1.2 Dualjet and 1.2 VVT

Other comparisons

With the 1.0 EcoBoost

With the 1.2 Dualjet and 1.2 VVT

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. Ford EcoBoost engineWikipedia · Other source · consulted 26 September 2026
  2. Alerta Ford: la correa de distribución del 1.0 EcoBoost puede romper el motor y la NHTSA ya investigaMotor16 · Motoring press · consulted 26 September 2026 · in Spanish
  3. Los Ford 1.0 EcoBoost tricilíndricos están dando problemas de correas bañadas que recuerdan al caso PureTechMotor.es · Motoring press · consulted 26 September 2026 · in Spanish
  4. Gripa el motor por problema en el manguito se queda sin refrigeranteOpinautos · Owners' forum · consulted 26 September 2026 · in Spanish
  5. Suzuki motor KWikipedia · Other source · consulted 27 September 2026 · in Spanish
  6. Suzuki K engineWikipedia · Other source · consulted 27 September 2026
  7. Suzuki Swift (NZ) – Typische Probleme & SchwachstellenGebrauchtwagenberater.de · Motoring press · consulted 27 September 2026 · in German
  8. Suzuki Splash (2008–2014) – Bekannte Probleme & KrankheitenGebrauchtwagenberater.de · Motoring press · consulted 27 September 2026 · in German
  9. Suzuki Ignis (MF, ab 2016) – Bekannte Probleme & SchwachstellenGebrauchtwagenberater.de · Motoring press · consulted 27 September 2026 · in German
  10. Prueba: Ford Fiesta 1.0 EcoBoost 100 CV (2013)km77 · Motoring press · consulted 26 September 2026 · in Spanish
  11. Ford Mondeo Berlina Trend 1.0 EcoBoost 92 kW (125 CV) (2015-2018): precio y ficha técnicakm77 · Technical documentation · consulted 26 September 2026 · in Spanish
  12. Ford B-MAX Trend 1.0 EcoBoost 100 CV (2012-2018): precio y ficha técnicakm77 · Technical documentation · consulted 26 September 2026 · in Spanish
  13. Suzuki Ignis : avis, qualités et défauts des propriétairesFiches-auto.fr · Owners' forum · consulted 27 September 2026 · in French
  14. Suzuki Swift 2 : avis, qualités et défauts des propriétairesFiches-auto.fr · Owners' forum · consulted 27 September 2026 · in French
  15. Ford EcoBoost engines: reliability, problems and should you buy one?Carbuyer · Motoring press · consulted 26 September 2026
  16. Ford's Self-Clogging 1.0-Liter EcoBoost Engine Is Finally Getting RecalledThe Drive · Motoring press · consulted 26 September 2026
  17. The Largest Ford EcoBoost Recalls In 15 Years Of ProductionCarBuzz · Motoring press · consulted 26 September 2026
  18. Stellantis no es el único afectado por la correa de distribución bañada en aceiteAutofácil · Motoring press · consulted 26 September 2026 · in Spanish