IsItAGoodCar
Reliability Guide

Common Problems with the
2015–2018 Ford S-MAX Mk2

We've identified 4 known issues that can affect the 2015–2018 Ford S-MAX Mk2. 3 of these are serious faults that could be expensive to repair.

4
Known Issues
3
Serious
0
Moderate
1
Minor

All Known Issues

1.5 EcoBoost Cylinder Block Coolant Intrusion & Overheating

SeriousEngine

A structural slit between the cylinder bore liners allows engine coolant to breach the head gasket and leak directly into cylinders 2 and 3, causing engine misfires, white exhaust vapor, and fatal engine seizure.

Est. Repair Cost: £1,800–£4,500
Warning Signs:

Lumpy cold start idle with shaking engine, Thick sweet-smelling white smoke on startup, Low coolant level warning light without external puddle

What to Inspect:
  • Inspect coolant expansion tank for oil sheen or low level
  • Ask for service records proving fitment of revised engine short-block
Verified by IsItAGoodCar Research TeamUpdated

PowerShift 6-Speed Dual-Clutch (6DCT450) Valve Body Shudder & TCM Faults

SeriousGearbox & Transmission

The 6-speed wet dual-clutch transmission suffers from clutch wear debris clogging internal solenoids in the mechatronic valve body, causing harsh engagement, slipping, and gearbox limp mode.

Est. Repair Cost: £800–£2,200
Warning Signs:

Violent shuddering through seat when pulling away in 1st gear, Delayed gear engagement when selecting drive or reverse, "Transmission Malfunction Service Now" warning message

What to Inspect:
  • Test pull-away smoothness from a standstill with steering straight and on full lock
  • Check service history for 3-year / 37,500-mile transmission fluid renewals
Verified by IsItAGoodCar Research TeamUpdated

Electric Power Steering (EPAS) Motor Drive Belt Snapping & Sudden Assist Loss

SeriousSteering

The internal toothed belt driving the recirculating ball steering rack from the electric assist motor degrades from road spray and salt, snapping and instantly leaving the driver with heavy unassisted steering.

Est. Repair Cost: £600–£1,400
Warning Signs:

Sudden heavy steering with "Steering Assist Fault" warning message, High-pitched whirring from steering rack when turning wheel, Notchy steering feel around straight ahead

What to Inspect:
  • Rotate steering wheel lock-to-lock at idle listening for belt slipping or grinding
  • Scan for EPAS steering angle sensor or motor torque fault codes
Verified by IsItAGoodCar Research TeamUpdated

Panoramic Glass Sunroof Roller Blind Guide Rail Jam & Motor Strip

MinorInterior & Trim

The cables and plastic guide runners for the electric panoramic roof roller blind jump their tracks or snap, jamming the blind in a half-open position and stripping the plastic motor drive gears.

Est. Repair Cost: £200–£550
Warning Signs:

Roller blind moves unevenly or catches on one side, Grinding or clicking sound from overhead console when operating blind, Blind stuck open or closed

What to Inspect:
  • Operate panoramic sunblind fully open and fully closed multiple times
  • Listen for clicking gear teeth in the roof lining
Verified by IsItAGoodCar Research TeamUpdated

Buying Tips for 2015–2018 Ford S-MAX Mk2

  • ✓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.
2019
Check a 2015–2018 Ford S-MAX Mk2 by Registration