The 2017 C1 III shares its platform with the Peugeot 108 and Toyota Aygo—a budget city car with simple mechanicals but some notable engine durability issues, particularly on the 1.2 PureTech three-cylinder. Transmission mounts wear prematurely, and the naturally-aspirated 1.0 VTi is generally more reliable than its turbo sibling.
1.2 PureTech Wet Timing Belt Failure
Common · high severityTypical onset: 40,000-80,000 mi
Symptoms: Metallic rattling on cold start, Oil contamination with white milky residue, Check engine light with timing-related codes, Catastrophic engine failure if belt disintegrates
Fix: The timing belt runs in oil and deteriorates prematurely, shedding material into the oil system. Requires timing belt replacement (3-4 hours) but often discovered after engine damage occurs, necessitating cylinder head work or full rebuild (12-18 hours). PSA issued extended warranty coverage in some markets but many 2017s are now outside that window.
Estimated cost: $800-1,200 for preventive belt replacement; $3,500-6,500 for head gasket/valve work after failure
Hydraulic Lifter Collapse (1.2 PureTech)
Common · medium severityTypical onset: 50,000-90,000 mi
Symptoms: Ticking or tapping noise from valve train, worst when cold, Noise persists after oil changes, Progressive loss of power, Can lead to bent valves if ignored
Fix: Hydraulic lifters fail due to oil contamination from the wet belt issue or extended service intervals. Replacing all lifters requires cylinder head removal (8-10 hours). Often done alongside timing belt and head gasket as a comprehensive repair.
Estimated cost: $1,800-3,200
Transmission Mount Failure
Common · low severityTypical onset: 60,000-100,000 mi
Symptoms: Clunking when shifting from park to drive/reverse, Excessive vibration at idle, Visible engine movement when revving in park, Gear lever feels notchy or imprecise
Fix: The upper transmission mount (torque mount) degrades from the three-cylinder's inherent vibration. Replacement is straightforward (1.5-2 hours) but requires supporting the drivetrain. OEM mounts last longer than aftermarket.
Estimated cost: $250-450
EGR Valve and Intake Carbon Buildup
Occasional · medium severityTypical onset: 70,000-110,000 mi
Symptoms: Rough idle and hesitation on acceleration, Check engine light with P0400-series EGR codes, Reduced fuel economy, Failed emissions testing
Fix: Short-trip driving accelerates carbon accumulation in the EGR valve and intake manifold. EGR valve replacement (1.5 hours) plus intake cleaning (2 hours) or manifold replacement. More common on PureTech engines.
Estimated cost: $400-750
Harmonic Balancer Deterioration (1.0 VTi)
Occasional · medium severityTypical onset: 80,000-120,000 mi
Symptoms: Chirping or squealing from front of engine, Visible wobble on the crankshaft pulley, Vibration felt through steering wheel, Serpentine belt wear or misalignment
Fix: The rubber damper ring separates from the hub, causing imbalance. Replacement requires serpentine belt removal and careful torquing of the crankshaft bolt (2-2.5 hours). Use OEM part—aftermarket failures are common.
Estimated cost: $350-550
Fuel System Contamination from Poor-Quality Fuel
Occasional · medium severitySymptoms: Hard starting or extended cranking, Rough running and misfires, Stalling after refueling, Fuel smell in cabin or visible leaks
Fix: The small-displacement engines are sensitive to contaminated fuel. Symptoms often appear after filling at off-brand stations. Requires fuel filter replacement (0.5 hours), sometimes fuel system flush and injector cleaning (2-3 hours). Severe cases need tank drop and cleaning.
Estimated cost: $150-300 for filter; $500-900 for full system service
Buy the 1.0 VTi manual if you need cheap city transport and can live with 72 hp; avoid the 1.2 PureTech entirely unless timing belt and lifters have documented recent replacement—too many grenaded engines out there.
AI-assisted summary drawn from NHTSA recall data, our labor-times database, and platform knowledge. Not a substitute for a pre-purchase inspection on a specific vehicle.