1.0 EcoBoost vs 1.2 12V: which engine is more reliable?

According to our risk index, the 1.2 12V carries less risk than the 1.0 EcoBoost: 57/100 versus 71/100 (both 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 12V has 2 documented serious faults, the main one being «Timing chain stretch and tensioner wear».

Risk index

1.0 EcoBoost

High risk · 3 serious faults

Risk index

1.2 12V

High risk · 2 serious faults

Lower risk

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

Reviewed on 27 September 202620 sources How 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 12V reliable?

The 1.2 12V is a simple, low-power, naturally aspirated three-cylinder engine (54-70 hp), with two documented design faults: the timing chain tensioner, which can end up destroying the engine, and -on the Volkswagen Polo IV- a catalytic converter too close to the cylinder head that can burn the exhaust valves. Ignition coil failures are also common, and there are isolated cases of oil consumption and vibration.^{[5][6][7][8][9]}

See the 5 of the 1.2 12V faults

Side-by-side comparison

Comparison of 1.0 EcoBoost and 1.2 12V
Item	1.0 EcoBoost	1.2 12V
Technical data
Type	Engine	Engine
Fuel	Petrol	Petrol
Displacement	999 cm³	1,198 cm³
Timing	Wet belt (belt-in-oil)	Chain
Power	100–155 hp	54–70 hp
Production	since 2012^{[1][10][11][12]}	2001–2014^[5][13][14]
Reliability
Risk index (what is it?)	71High risk	57High risk
Documented faults	4	5
Of high or critical severity	3	2
Worst severity	Critical severity	Critical severity
Main faults	Critical severity: Degradation of the timing belt running in oil Critical severity: Oil pump belt and tensioner failure Critical severity: Coolant leaks and overheating from the turbo hose	Critical severity: Timing chain stretch and tensioner wear High severity: Cylinder head and valve damage from exhaust gas backflow (Volkswagen Polo IV) Medium severity: Higher-than-normal oil consumption
Most expensive documented repair	up to €1,200Degradation of the timing belt running in oilPublished figure^[2]	No reliable data
Which versions to buy
BuyRecommended versions	None	None
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]	1.2 54/60 hp (AWY, BMD, BBM, 2001-2014)^[5][7] 1.2 64/70 hp (BME, CGPA, 2002-2014)^{[5][7][19][20]}
AvoidVersions to avoid	None	None

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 12V

See the 7 models with the 1.2 12V

Other comparisons

With the 1.0 EcoBoost

With the 1.2 12V

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Sources

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

Ford EcoBoost engineWikipedia · Other source · consulted 26 September 2026
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
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
Gripa el motor por problema en el manguito se queda sin refrigeranteOpinautos · Owners' forum · consulted 26 September 2026 · in Spanish
VW Polo 4 (9N): Typische Probleme & SchwachstellenGebrauchtwagenberater.de · Motoring press · consulted 27 September 2026 · in German
Fiabilité et pannes de la Volkswagen Polo 4Fiches-auto.fr · Motoring press · consulted 27 September 2026 · in French
Fiabilité et pannes de la Seat Ibiza (2008-2017)Fiches-auto.fr · Motoring press · consulted 27 September 2026 · in French
Seat Ibiza III (2002-2008): Bekannte Probleme & KrankheitenGebrauchtwagenberater.de · Motoring press · consulted 27 September 2026 · in German
Fiabilité et pannes de la Seat Ibiza (2002-2008)Fiches-auto.fr · Motoring press · consulted 27 September 2026 · in French
Prueba: Ford Fiesta 1.0 EcoBoost 100 CV (2013)km77 · Motoring press · consulted 26 September 2026 · in Spanish
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
Ford B-MAX Trend 1.0 EcoBoost 100 CV (2012-2018): precio y ficha técnicakm77 · Technical documentation · consulted 26 September 2026 · in Spanish
VW EA111Wikipedia (alemán) · Other source · consulted 27 September 2026 · in German
VW Polo IVWikipedia (alemán) · Other source · consulted 27 September 2026 · in German
Ford EcoBoost engines: reliability, problems and should you buy one?Carbuyer · Motoring press · consulted 26 September 2026
Ford's Self-Clogging 1.0-Liter EcoBoost Engine Is Finally Getting RecalledThe Drive · Motoring press · consulted 26 September 2026
The Largest Ford EcoBoost Recalls In 15 Years Of ProductionCarBuzz · Motoring press · consulted 26 September 2026
Stellantis no es el único afectado por la correa de distribución bañada en aceiteAutofácil · Motoring press · consulted 26 September 2026 · in Spanish
Fiabilité et pannes de la Volkswagen Polo 5Fiches-auto.fr · Motoring press · consulted 27 September 2026 · in French
Fiabilité et pannes de la Skoda Fabia 2Fiches-auto.fr · Motoring press · consulted 27 September 2026 · in French