Timing belt and tensioner (80,000 km): EW7 is an interference engine; OE interval is 80k/5yr but tensioner bearing seizes in BG/FR climates earlier; catastrophic valve contact if belt snaps Fix: Replace belt, hydraulic tensioner, idler pulley and water pump as complete kit [OEM: 0831.T7]
Throttle body (electronic, Siemens EMS) (100,000 km): Carbon build-up on throttle plate and idle speed track causes sticking and erratic idle; EML with P0505/P0506 Fix: Remove and clean with throttle cleaner; perform throttle body relearn via PP2000/Lexia after cleaning [OEM: 1628055680]
Coil pack (single or pair failure) (120,000 km): EW7 uses 4 individual coils (coil-on-plug from 16V version); heat and age cause insulation breakdown causing misfire on one or two cylinders Fix: Replace faulty coil(s); swap coils between cylinders to confirm diagnosis before purchase [OEM: 5970.83]
Camshaft oil seals (inlet + exhaust) (90,000 km): Rubber seals harden on DOHC 16V head; oil weeps onto timing belt causing accelerated belt degradation Fix: Replace both cam seals; replace timing belt if oil-contaminated [OEM: 0249.F1]
The upstream oxygen sensor ages and can drift, causing fuelling adaptation to reach its limits; results in rough idle and increased fuel consumption. Replace with an OE-spec sensor and confirm fuel trims return to normal with live data.
Coolant temperature sensor (Bosch Motronic input) (80,000 km): Sensor bias causes over-fuelling or under-fuelling on warm-up; common on 406/C5 high-mileage examples Fix: Replace with OE sensor; never use generic resistor replacements - fuelling strategy is highly sensitive [OEM: 1338.A5]
Common torque specifications
Cylinder Head Bolts Nm
20 Nm + 240 deg (single-angle, stretch bolts, do not re-use) — TTY, replace bolts (single-use) unconfirmed
PSA 0132-Z - camshaft alignment tool set (DOHC EW7)
Lexia 3 / PP2000 - throttle body relearn and coil diagnosis
PSA 0153-MN - timing belt tensioner adjustment tool
Pro tips from the field
Always replace the water pump with the timing belt kit on EW7 - the pump is driven by the belt and failure strands the car; the extra part cost is negligible against the labour duplication.
After throttle body cleaning, the Siemens EMS requires a learned idle relearn: ignition ON for 30 s, engine start, warm to temperature, idle for 2 minutes - skipping this causes hunting idle complaints.
PSA part numbers use a dot notation - always quote the full PSA code when ordering; generic belt kits without the correct hydraulic tensioner cause immediate belt flutter and premature wear.
On 406 and C5, EW7 cooling system bleeds poorly if the heater matrix bleed screw is ignored; always open the heater bleed point first and top up until steady coolant flow - air locks cause overheating within 10 km.
Got a EW7 problem? Ask for free.
Describe the symptoms — TorqFix replies with a diagnosis cited from verified workshop data.
TorqFix was built by a mechanic — after a 2,700 km drive with five roadside repairs that no diagnostic tool could explain.
The figures on this page come from manufacturer workshop documentation and are shown as they are. The page is assembled automatically from that data — it is not written by an AI. The AI works in the chat, where it answers for your specific car. It writes nothing here.
Variants of the same model differ. Cross-check torque against the factory manual for your engine before final tightening.
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