Rear Auxiliary Heater Underbody Pipe Corrosion and Coolant Loss
SeriousCooling SystemThe 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.
Puddle of pink or green coolant on the ground beneath the centre or rear floorpan of the car, Loss of cabin heating output accompanied by rising temperature gauge reading, Coolant header tank level repeatedly dropping below minimum mark
- Look underneath the vehicle along the chassis rails for dampness, crusty coolant crystallization, or corroded metal pipe runs
- Inspect the engine coolant expansion bottle with the engine cold to ensure the level is correct and pressure seals are intact
- Turn the rear climate control fan on high to confirm hot air blows through the rear passenger vents