2007 KIA Sedona 2.9L Diesel · HN57 UCS

The Sedona features a dedicated rear passenger heater matrix supplied by metal coolant lines routed along the underside of the vehicle chassis. Exposed directly to road salt, grit spray, and damp UK winter conditions, these steel pipes corrode and eventually develop pinhole perforations. Coolant leaks out rapidly beneath the car, leading to sudden engine overheating and potential cylinder head gasket failure if the driver fails to notice the dropping coolant gauge. Replacing the metal lines with upgraded rubber hoses or aluminium lines is a well-known specialist fix.

Higher-specification second-generation Sedonas (such as the TS and 3 trim grades) feature electrically operated power-sliding rear side doors. The drive mechanisms rely on steel tension cables, plastic pulleys, and microswitch sensors located within the rear quarter panels and sill runners. With age, road grit accumulates in the lower floor tracks, door seals stick, and the steel drive cables fray or snap. When this occurs, the electric motor jams, leaving the door unable to open or latch shut automatically, necessitating manual override or expensive cable kit renewal.

The Delphi common-rail high-pressure injection pump fitted to the 2.9-litre CRDi diesel engine is prone to internal mechanical degradation. As the internal cam and rollers break down, they shed microscopic metallic swarf into the fuel lines, contaminating the common fuel rail, clogging the fuel filter, and jamming the diesel injectors. Early warning signs include engine power surging, severe hesitation under acceleration, and prolonged cranking before starting. Left unresolved, the metal debris circulates through the entire fuel system, requiring a full fuel tank flush or replacement alongside new pump and injectors.

On automatic Sedona models, the electronic transmission output speed sensor mounted atop the gearbox casing suffers from heat fatigue and internal circuit failure. When signal output to the transmission control module drops out, the gearbox abruptly triggers failsafe mode, locking into third gear while cruising on the motorway and refusing to shift into top gear or overdrive. Drivers also report erratic gear hunting, delayed engagement, and severe jolts when shifting into Drive at a standstill. Renewing the speed sensor and wiring plug is essential to restore proper shift operation.

On second-generation (VQ) Sedona models, the front lower suspension control arms suffer from accelerated structural corrosion caused by inadequate factory protective coating on their internal steel surfaces. Salt-laden road spray enters drainage apertures and rusts the wishbone arms from the inside out, severely weakening the metal stamping. In severe cases, corroded suspension arms can fracture during hard cornering or braking, causing loss of steering control. The fault was subject to UK DVSA safety recall R/2014/012 and represents a critical MOT inspection point.