Citroën C4
The EP6 VTi (N12/EP6C) is the naturally aspirated variant of the Prince engine without direct injection, making it less susceptible to intake valve carbon build-up than the THP. The early production chain tensioner issue is known; PSA improved the tensioner from 2012. Regular oil changes every 10,000 km are mandatory.
Modern compact
120 hp VTi in the C4 I — well-balanced everyday engine with good temperament. The naturally aspirated character feels more natural than the THP but lacks turbo torque.
Engine Weaknesses 6
Early EP6 VTi engines (pre-2012) suffer from a weak hydraulic chain tensioner that rattles on cold starts. The single-row timing chain stretches when tensioner pressure drops, causing valve timing to shift. PSA documented oil leaks from the chain tensioner between April 2010 and April 2011.
Symptoms: Rattling or chattering from the timing chain area for several seconds after cold start, occasionally also at operating temperature when oil level is low
The hydraulic chain tensioner on the EP6 VTi is a known weakness at PSA and BMW. The tensioner loses oil pressure when stationary, causing the chain to rattle on cold start and risk jumping a tooth.
Symptoms: Loud rattling on cold start that disappears after a few seconds, engine check light, camshaft position sensor fault code
The oil separator (PCV diaphragm) in the EP6 valve cover tears and routes unfiltered oil into the intake tract. This leads to elevated oil consumption, coking of the intake valves and visible oil in the intake hose.
Symptoms: Elevated oil consumption without visible external leak, oil in intake hose, blue smoke after cold start, power loss from contaminated intake valves
The EP6 VTi exhaust valves in particular suffer from premature valve stem seal wear. Oil sprays into the combustion chamber and forms carbon deposits on the valve faces, progressively reducing engine efficiency.
Symptoms: Blue smoke on cold start or during overrun, high oil consumption above 0.5 l/1,000 km, black deposits on spark plugs
The thermostat housing with integrated sensor on the EP6 VTi has design weaknesses. For older C3 production years up to end of 2013 Citroën officially issued a fix via an additional temperature sensor.
Symptoms: Slight coolant smell, falling coolant level, temperature gauge fluctuates, occasional overheating warning
The solenoids for variable camshaft timing (VVT) on the EP6 VTi wear over time and eventually produce fault codes P0014 or P0016. Replacement is inexpensive but is often ignored for too long.
Symptoms: Power loss especially in the mid rev range, rough running, engine check light, fault codes P0014 or P0016
Vehicle Weaknesses 6
The BSI (Body Systems Interface) on the C4 I is known for sporadic failures that lead to total failure of multiple vehicle systems. Moisture ingress into connectors promotes corrosion.
According to MOT statistics, brake discs on the C4 I wear above average, develop scoring and rust at the edges. MOT testers flag this frequently.
Driveshafts and axle joints on the C4 I are flagged above average by MOT testers. Steering joints and tie rod ends wear quickly, especially at higher mileages.
According to ADAC breakdown statistics, the C4 I is frequently flagged for flat batteries and failed starters. Permanent consumers in the standby current circuit can discharge the battery unnoticed.
According to MOT reports, the exhaust system on the C4 I rusts above average. Testers flag corroded exhaust pipes and clamps, which can lead to perforation and exhaust gas escape.
According to MOT statistics, headlights on the C4 I are one of the most frequently flagged items. Both low beam and tail lights are affected by failures and misadjustment.
