Ford Fiesta ST
147 kW three-cylinder EcoBoost in the Fiesta ST HJ and Puma ST — Ford's bold move from four- to three-cylinder in the ST segment. 320 Nm peak torque between 2,500 and 3,500 rpm. A balance shaft compensates for the three-cylinder's inherent roughness, though a perceptible resonance remains at 2,800–3,000 rpm — classified as normal by Ford. In Sport mode the sound gains a slightly bassier note. Turbo wastegate rattle on some examples is known from new. Thermally loaded considerably harder than production versions — diligent maintenance is essential.
The Three-Cylinder Sceptic Becomes a Fan
Three cylinders in an ST? In Sport mode it sounds a note deeper, the chassis rewards technique over brute force. 200 hp, 0–62 in 6.5 seconds — once you understand how it wants to go round corners, you're hooked.
Engine Weaknesses 7
The 1.5L engine tuned to 147 kW has increased overheating risk under sustained high-load driving. Cooling system and cylinder head are heavily stressed.
Symptoms: Temperature warning during extended track use, coolant loss, power reduction from engine protection.
The 1.5 EcoBoost YZJA has a known cooling system weakness. Coolant leaks internally and can reach the turbocharger. Ford issued a recall on 2017 vehicles and retrofitted an additional sensor.
Symptoms: Falling coolant level, white exhaust smoke, overheating warning, power loss, turbo noises in extreme cases.
Early 1.5 EcoBoost four-cylinder engines (up to approx. March 2019) are prone to hairline cracks in the cylinder block. Coolant enters the cylinders and causes severe engine damage. Short block replacement required.
Symptoms: Rough cold start, white exhaust smoke, coolant loss without external leak, engine warning light.
Individual 1.5 EcoBoost engines show piston ring fractures from as low as 35,000 km. The affected cylinder loses compression completely; short block replacement required.
Symptoms: Sudden power drop, heavy juddering or engine stall, measurable compression loss in one cylinder.
The high-output turbo shows accelerated wear with frequent track days or spirited daily use. Bearing leaks and elevated oil consumption appear earlier than in standard versions.
Symptoms: Oil smoke from exhaust, quiet whistling/whirring from turbo, rising oil consumption.
Direct injection causes carbon deposits, which can accumulate faster in ST models with frequent full-throttle short-trip use.
Symptoms: Stumbling on cold start, gradual power loss over time.
The turbo wastegate rattles audibly on some units even when new, on overrun. Ford dealers replace the wastegate assembly under warranty; the problem can recur after some time.
Symptoms: Metallic clicking or rattling on overrun, especially after spirited driving with warm engine
Vehicle Weaknesses 7
Recall 21S13 for 1,568 vehicles (Feb–Mar 2021): seatbelt can tear and thus lose its protective function. Check recall status without delay.
The MK8's manual gearbox jumps out of 1st and 3rd gear. Cause: worn shift forks (sliding pieces) and excessive play at the gear lever. Early diagnosis recommended.
Plastic door edge protector strips break or detach from the door skin. Replacement is surprisingly expensive. Common cause: parking damage and thermal expansion.
The electronic immobiliser develops sporadic malfunctions from 80,000–100,000 km. Tyre pressure sensors become unreliable from 50,000–70,000 km and need replacing.
Rear shock absorbers leak and springs break through corrosion — the same pattern as the predecessor. The loaded rear axle is particularly vulnerable with a fully laden vehicle.
Rust and paint flaking develop at the door hinges on MK8 vehicles from around 50,000 km. Left untreated, rust can spread to the door bodywork.
The SYNC 3 infotainment on the MK8 shows Bluetooth audio drop-outs at low speeds and occasionally frozen screen displays. Software updates from Ford are partially available.
Reports & Tests
189 owner complaints filed with NHTSA (2017–2023). Most reported: Powertrain (52), Engine (32), Other (26).