Inlet Manifold Swirl Flap Failure
SeriousEngineThe 1.8 and 2.0 Duratec HE 16V petrol engines feature variable-geometry plastic swirl flaps inside the intake manifold runners to enhance low-end turbulence. Over time, engine heat and vibration wear the plastic flap bearings loose on their square steel operating spindle. The flaps rattle loudly at idle, and eventually fatigue until the plastic flaps or brass screws detach and are sucked into the combustion chambers, causing catastrophic valve, piston, and cylinder wall destruction.
Ticking or loud plastic rattling noise from the intake manifold at idle (resembling a diesel engine), Rattling sound abruptly stops when the vacuum pipe to the manifold actuator is disconnected, Erratic idle speed, minor hesitation, and occasional misfire codes stored in the ECU, Sudden catastrophic engine failure if detached swirl flap debris enters the combustion chamber
- Listen closely to the black plastic intake manifold at idle for a prominent clattering rattle
- Pull off the small vacuum hose from the swirl flap solenoid; if the rattle vanishes, flaps are worn
- Check service records to see if an upgraded manifold or swirl flap delete has been carried out