Ford S-Max

The copper sealing washers at the injector seat fail and allow soot to enter the engine oil. The soot blocks the mesh filter in the turbo oil feed. This is the primary cause of turbocharger damage on this engine. Replacing all injector seals is a known maintenance item.

Symptoms: Diesel smell inside the cabin, black deposits around injectors, smoke from the engine bay, subsequent turbocharger damage

Soot from leaking injector seals blocks the fine mesh filter in the turbo oil feed (banjo bolt). Below 0.8 bar oil pressure the turbocharger fails. A complete repair includes the turbo, oil sump, oil strainer, oil filter housing and intercooler. Costs run to £1,300–£2,200.

Symptoms: Whistling from the turbo area, power loss, blue smoke clouds, oil in the intake tract

At higher mileages the high-pressure pump wears internally and leaves metal swarf in the fuel filter. Swarf can damage injectors. The pump can fail suddenly on the motorway.

Symptoms: Golden metal swarf in the diesel filter housing, engine drops into limp mode or stalls under full load, difficult cold starting.

Ford specifies 200,000 km or 10 years as the replacement interval (automatic: 100,000 km). A belt with 15 cm of missing teeth has been documented at only 99,000 km. Belt failure destroys rocker arms and the camshaft.

Symptoms: No prior warning on belt snap — sudden engine stall on the motorway, loud banging from the engine.

The copper washers and O-ring seals on the injectors burn through, allowing combustion gases and fuel to escape into the valve cover area. This leads to hardened oil deposits.

Symptoms: Diesel smell in the engine bay, oily soot deposit around the valve cover, rough idle, visible smoke from the crankcase ventilation system.

The mesh filter in the oil feed line to the turbocharger clogs with metal swarf and oil carbon. The turbo runs without sufficient lubrication, leading to bearing damage.

Symptoms: Sudden power loss, whistling or howling from the turbo area, blue exhaust smoke, increased oil consumption.

The 1.6 TDCi is particularly prone to DPF blockages. In predominantly short-trip use the engine never reaches sufficient exhaust temperature for self-cleaning. Fuel entering the engine oil through failed regeneration cycles raises the oil level measurably.

Symptoms: Engine management light, power loss, elevated oil level, frequent prompts to take a motorway run

From 75,000–100,000 km, poorly maintained examples develop axial play in the turbocharger shaft. The oil feed line to the turbo can coke up, leading to oil starvation.

Symptoms: Whistling or metallic rattling on acceleration, power loss, bluish smoke.

An overflowing windscreen washer reservoir damages the wiring harness that runs below it. Cable insulation is attacked by the fluid, which can lead to engine stalling, AC failure and fault code P0003.

The central locking on the S-Max WA6 is known to be fault-prone: doors open spontaneously or cannot be opened, particularly the tailgate. In the worst case doors open while driving.

According to TÜV reports, the S-Max WA6 frequently has suspension, steering and driveshaft issues flagged. Broken front springs and worn driveshaft CV boots are typical.

The TPMS tyre pressure sensors on the S-Max WA6 corrode at the valve stem and mounting, causing seal failure. In the worst case the valve can fracture and cause sudden pressure loss, especially at higher speeds.