Ford S Max Engine Malfunction

When my Ford S-Max’s engine gave out, the $4,000 repair quote gave me heart palpitations. What causes these family haulers’ turbocharged motors to fail catastrophically? Let’s diagnose the S-Max’s costly Achilles’ heels and hopefully keep your wallet intact.

Problem Explanation

The Ford S-Max is a multi-purpose vehicle (MPV) that has had issues with engine malfunctions across various models and years. These malfunctions can manifest in symptoms like the engine not starting, stalling, misfiring, loss of power, rough idling, or abnormal engine noises. The engine may go into limp-home mode to protect itself when faults are detected. An engine malfunction indicates one or more components or systems is not operating properly, leading to reduced performance, drivability issues, and potentially catastrophic engine failure if left unchecked.

Potential Causes of Engine Malfunction

Common Issues

Faulty sensors are a prevalent cause of Ford S-Max engine issues. The mass air flow (MAF) sensor can get contaminated over time and provide inaccurate data to the engine computer, leading to improper fuel trim and ignition timing. An oxygen sensor monitors exhaust gases to regulate fuel mixture, and failure triggers performance issues. Likewise, malfunctioning spark plugs and coil packs waste spark energy and misfire cylinders.

The fuel system relies on a high-pressure fuel pump to deliver pressurized gasoline to injectors. A clogged fuel filter starves engine components of fuel, while pump failure cuts off the vital supply altogether. Bad injectors fail to meter fuel correctly, disrupting the air-fuel ratio and combustion.

A restricted air filter diminishes airflow into the turbocharged engine, reducing intake volume and leading to decreased boost pressure. Cracks in intake piping create boost and vacuum leaks that also detrimentally impact performance.

Model-Specific Problems

Diesel Models:

Turbocharger issues plague Ford’s diesel S-Max variants. Boost pressure hoses can crack over time and cause boost leaks, throwing off the turbo system. The variable-geometry turbo relies on a vacuum actuator and swing mechanism to optimize boost – components that are prone to sticking and failure with high mileages. Oil supply issues leading to turbo bearing wear can also necessitate replacement.

The diesel particulate filter (DPF) traps soot from exhaust gases, but may become prematurely clogged if not regularly regenerated through sustained highway driving. This blocks exhaust flow entirely, cuts engine power severely, and requires costly DPF cleaning or replacement. Faulty injectors struggle to atomize fuel correctly in the cylinder, leading to incomplete combustion and excess particulate emissions that exacerbate DPF issues.

Gasoline Models:

Timing chain stretch is common on the transverse-mounted 2.0L and 2.3L EcoBoost engines, which can cause cam timing to go out of calibration and create a raft of driveability and performance issues. The tensioning system may also fail randomly and cause the chain to snap entirely, usually resulting in major internal engine damage from catastrophic timing failure.

Deposits on intake valves disrupt airflow and cause decarbonization issues over time. These deposits inhibit valve sealing, blowby gases during the combustion cycle, power loss, and misfires as a result. Faulty valve lifters and lash adjusters can also impact valve operation and lead to similar drivability problems.

Diagnosing the Engine Malfunction

Diagnostic trouble codes (DTCs) provide the starting point for identifying and addressing engine malfunctions. Connecting an OBD2 scanner pulls codes from modules like the PCM, TCM, ABS, SRS, and more to isolate fault areas. A seasoned technician can analyze the DTCs to zone in on root causes – for example, misfire codes point to ignition components like spark plugs and coils. They may need to reference factory technical service bulletins (TSBs) detailing model-specific issues and recommended repairs.

Additional testing helps validate diagnostic theories from trouble codes. A compression test indicates worn piston rings or leaking valves if readings are low or very inconsistent across cylinders. During a cylinder leakdown test, individual cylinders are pressurized to pinpoint where combustion gases are escaping – through valves or piston rings generally. These test results allow accurate targeting of internal engine repairs.

A visual inspection also provides clues to potential issues. The technician will check for external leaks from hoses, seals, gaskets, etc. They can also look for sludge buildup around vital components like oil pans, transmission fluid lines, axle breathers pointing to underlying problems. Test driving the vehicle often highlights running issues too.

Repairing the Engine Malfunction

DIY repairs save on labor costs but require advanced mechanical competence, special tools, safety know-how, and manifold risks in working with complex engine systems.

Severe malfunctions often necessitate professional diagnosis and repair from specialist mechanics. They have the expertise to fully identify issues, accurately quote repair costs, use advanced diagnostics software, and properly replace components. Complex tasks like timing chains, turbo/valve repairs require engine removal and facilities larger than a home garage.

Common options for correcting engine faults include:

• Sensor replacements after verifying connectivity issues and corrosion damage.
• Injector cleaning using specialty fluid kits to restore flow and spray patterns. Complete injector replacement may be needed for permanent faults.
• Turbocharger rebuilds or replacements to rectify worn bearers, sticking vanes, oil supply faults and more.
• Full timing chain kit installations is a race against time once slack is observed. This comprehensive service avoids further catastrophic damage.

Reputable workshops source OEM or equivalent aftermarket replacement parts to maintain reliability and durability. Bargain parts often fail prematurely or cause ancillary damage. Routine maintenance plays a key role in heading off major repairs down the road as well.

Cost of repairing

Repair costs vary widely depending on the specific fault, availability of parts, mechanic rates etc. Minor issues like oxygen sensor replacements may only run $150-200. More complex turbo or timing chain repairs often exceed $2000+ at specialized shops, but are critical to restore engine function and longevity.

Severe engine damage from timing chain snap, bearing failure or similar can necessitate a long block or used engine replacement costing up to $6000+ parts and labor. Preventative maintenance significantly reduces repair costs long-term.