IsItAGoodCar
Reliability Guide

Common Problems with the
2016–2017 Ford Mustang (S550)

We've identified 3 known issues that can affect the 2016–2017 Ford Mustang (S550). 1 of these are serious faults that could be expensive to repair.

3
Known Issues
1
Serious
2
Moderate
0
Minor

All Known Issues

RHD Engine Oil-to-Water Cooler Heat Exchanger Rupture

SeriousCooling System

Right-hand-drive (RHD) S550 Mustang 5.0 V8 models require a specific oil cooler arrangement to clear the steering rack column. The factory-fitted water-to-oil heat exchanger mounted to the engine block is prone to internal wall fracture. When the internal barrier fails, high-pressure engine oil breaches the coolant circuit, rapidly emulsifying the entire cooling system into a thick brown sludge, causing coolant tank overflow, severe overheating, and white/blue exhaust steam. If not halted immediately, bearing failure or oil starvation ensues. Many UK owners fit aftermarket oil-to-air coolers to eradicate this failure point permanently.

Est. Repair Cost: £900–£2,500
Warning Signs:

Thick brown milky mayonnaise emulsion coating the coolant expansion tank, Sudden engine overheating warning and steam billowing from under the bonnet, Low oil pressure warning lamp illumination as oil escapes into the cooling jacket, Oil slick on the ground near the front subframe or underbody undertray

What to Inspect:
  • Inspect the transparent coolant header tank when cold for dark oil residue or foaming
  • Examine the engine oil dipstick to ensure oil level is not dropping and no coolant contamination is visible
  • Check the area around the oil filter housing and cooler sandwich plate for signs of weeping
  • Ask the seller if an upgraded aftermarket oil-to-air cooling kit has been fitted
Verified by IsItAGoodCar Research TeamUpdated

Boot Lid Wiring Loom Fatigue and Rear-View Camera Failure

ModerateElectrics & Electronics

The wiring harness running through the flexible rubber conduit connecting the rear body shell to the boot lid is subject to tight bending radius and tensile fatigue during normal opening and closing. Over repeated cycles, the internal copper conductors work-harden and snap. The primary consequence is the total failure of the factory reversing camera, displaying a black, flickering, or inverted image on the SYNC touchscreen. In severe cases, the boot release solenoid stops functioning, luggage compartment lighting fails, or the trunk lid ajar sensor triggers continuous false alarms on the dashboard.

Est. Repair Cost: £180–£550
Warning Signs:

Reversing camera screen is blank, flickering, or displays camera unavailable message, Electric boot release button on the exterior lid fails to unlock the trunk, Intermittent luggage compartment open warning displayed while driving, Boot interior light inoperative despite a good bulb and fuse

What to Inspect:
  • Select reverse gear while the engine is running to verify instant, stable camera feed on the central screen
  • Gently flex the rubber trunk wiring conduit while checking if the camera display cuts out or flickers
  • Test the boot release button on both the key fob and the trunk lid to ensure reliable operation
  • Check whether the vehicle has had the Ford recall or technical service campaign performed
Verified by IsItAGoodCar Research TeamUpdated

Air Conditioning Evaporator Core Leak Behind Dashboard

ModerateCooling System

A widespread manufacturing defect on sixth-generation Mustangs is premature corrosion and cracking of the air conditioning evaporator core located deep inside the HVAC heater casing behind the dashboard. The thin aluminum tubing develops micro-fractures, releasing R134a or R1234yf refrigerant into the cabin air ducts. Regassing the system provides only brief cooling before blowing ambient air again. Replacing the evaporator core requires a complete dashboard and centre console teardown, demanding 8 to 12 hours of workshop labor.

Est. Repair Cost: £900–£1,600
Warning Signs:

Air conditioning blows ambient warm air despite recent refrigerant regas, Hissing noise from the central air vents when the A/C button is pressed, Faint sweet or chemical refrigerant smell inside the cabin when ventilation is active, Oily residue accumulating at the cabin water drain outlet beneath the vehicle

What to Inspect:
  • Turn the dual-zone climate control to minimum temperature and verify icy cold air from all face vents
  • Ask for records of repeated air conditioning re-gasses, which indicates an active evaporator core leak
  • Use a UV blacklight on the condensation drain tube under the car to check for glowing leak dye
  • Listen for hissing or bubbling behind the centre console when engaging the air conditioning compressor
Verified by IsItAGoodCar Research TeamUpdated

Buying Tips for 2016–2017 Ford Mustang (S550)

  • On 5.0-litre V8 models, inspect the coolant expansion reservoir when cold for brown emulsified oil, indicating failure of the RHD-specific oil-to-water heat exchanger.
  • Test the central infotainment screen when selecting reverse gear; flickering or a blank display signals broken wiring inside the rubber boot lid hinge harness.
  • Turn the air conditioning to maximum cold on both driver and passenger zones to check for an evaporator core leak behind the dashboard, a costly repair if leaking.
  • Inspect the rear subframe bushes and differential mounts, and listen for driveline clunks on gear engagement, which can be addressed with popular aftermarket IRS support kits.
  • On manual GT variants with the Getrag MT82 gearbox, shift firmly into 2nd and 3rd gears at higher revs to ensure synchromesh rings and selector forks are undamaged.
20152018
Check a 2016–2017 Ford Mustang (S550) by Registration