What is the 1.5 EcoBoost Coolant Intrusion problem on a 2015 Ford S-MAX Mk2?

Reliability Guide

Common Problems with the
2015–2019 Ford S-MAX Mk2

We've identified 1 known issue that can affect the 2015–2019 Ford S-MAX Mk2. 1 of these are serious faults that could be expensive to repair.

Known Issues

Serious

Moderate

Minor

The 2015–2019 period has an average number of reported issues compared to other Ford S-MAX Mk2 year periods.

SeriousEngine

A design flaw in the 1.5 EcoBoost engine block can allow coolant to leak into the cylinders, leading to complete engine failure.

Most affected: 1.5 EcoBoost

Estimated cost: £2,000–£5,000Affects: 2015–2019

✓Avoid early 1.5 EcoBoost petrol models (pre-2019) due to well-documented issues with coolant intrusion into the engine cylinders, requiring a new engine.
✓Check the Powershift automatic gearbox (if fitted to early diesels) for shuddering; later models switched to a more reliable conventional torque converter.
✓Verify the SYNC 2 or SYNC 3 infotainment system works without freezing; SYNC 3 (post-2016) is highly preferred for Apple CarPlay/Android Auto support.
✓Inspect the power-folding rear seats (if optioned) to ensure the electric motors haven't failed or jammed due to trapped debris.
✓Listen for clunks from the front suspension when pulling away, indicating worn MacPherson strut top mounts or lower control arms.
✓Check the DPF and AdBlue systems on diesel models, as these large cars are often subjected to short, DPF-clogging urban journeys.