The 2017 Lincoln MKT shares the Ford Flex platform and offers two engines: a naturally-aspirated 3.7L V6 (reliable but unremarkable) and a 3.5L EcoBoost twin-turbo V6 (powerful but troublesome). The EcoBoost variants dominate the problem list with catastrophic engine failures that can turn this luxury crossover into a financial black hole.
3.5L EcoBoost Catastrophic Engine Failure (Carbon Buildup & Timing Chain)
Common · high severityTypical onset: 80,000-130,000 mi
Symptoms: Rough idle and misfires that progressively worsen, Check engine light with P0016/P0017 timing correlation codes, Rattling noise on cold start (timing chain stretch), Sudden loss of power or complete no-start condition, Metal shavings in oil during changes
Fix: Direct-injection EcoBoost engines suffer from severe carbon buildup on intake valves (no fuel wash) causing misfires, while timing chain stretch leads to jumped timing and valve-to-piston contact. Once timing jumps, you're looking at bent valves, damaged pistons, and often complete engine replacement. Carbon cleaning alone is 6-8 hours if caught early; engine replacement is 18-24 hours plus 2-4 weeks for a reman unit. Many owners discover this after a misfire turns into a no-start.
Estimated cost: $8,500-14,000
PTU (Power Transfer Unit) Fluid Neglect & Failure
Common · high severityTypical onset: 70,000-110,000 mi
Symptoms: Grinding or whining noise from front of vehicle during acceleration, Vibration when turning, Burning smell from under vehicle, AWD malfunction warning light, Metal shavings visible in PTU fluid
Fix: Ford lists PTU fluid as 'lifetime fill' but it absolutely is not. The fluid breaks down, the unit overheats, and the internal gears grenade themselves. If you catch it early with just noise, a fluid change (0.5 hours) might buy time, but most need full PTU replacement at 4-6 hours labor. The part is dealer-only and expensive. This is a known Ford AWD achilles heel across multiple platforms.
Estimated cost: $1,800-3,200
Transmission Oil Cooler Line Corrosion & Cross-Contamination
Common · high severityTypical onset: 60,000-100,000 mi
Symptoms: Transmission slipping or harsh shifts, Coolant in transmission (strawberry milkshake fluid), Oil in coolant reservoir (foamy or discolored), Transmission overheating warnings, Engine overheating in severe cases
Fix: The internal transmission cooler lines that run through the radiator corrode and fail, allowing coolant and ATF to mix. Once cross-contaminated, the transmission is destroyed (friction material swells, clutches fail). Requires new radiator, transmission flush or replacement, and all cooler lines. If caught immediately, a flush and radiator swap is 4-6 hours; if delayed, add transmission rebuild/replacement at 12-18 hours. This is a design flaw across Ford's 6-speed era.
Estimated cost: $2,000-7,500
Water Pump Failure (EcoBoost engines)
Occasional · high severityTypical onset: 60,000-90,000 mi
Symptoms: Coolant leak from front of engine, Squealing or grinding noise from accessory belt area, Engine overheating, Steam from under hood, Coolant warning light
Fix: The 3.5L EcoBoost uses an internal water pump driven by the timing chain, unlike most external pumps. When it fails, you risk overheating and engine damage. Replacement requires timing cover removal and chain work, making this a 8-10 hour job. Often discovered during timing chain service or after overheating event. Some techs replace it preemptively during timing work since you're already in there.
Estimated cost: $1,800-2,800
Rear Shock Absorber Mounting Point Fracture (Recall)
Occasional · medium severitySymptoms: Clunking noise from rear suspension over bumps, Visible rust or cracking around rear shock towers, Uneven tire wear, Rear end feels unstable or bouncy, Visual inspection shows shock tower separation
Fix: NHTSA recall 18V-046 addresses rear shock absorber mounting brackets that can fracture due to corrosion, particularly in salt-belt states. The bracket can separate from the body, causing loss of damping and potential control issues. Recall repair involves reinforcement plates welded to the shock towers, 2-3 hours per side if caught under recall. Non-recall repairs require structural welding and are 4-6 hours total.
Estimated cost: $0 (recall) or $800-1,500
Turbocharger Wastegate Rattle & Failure
Occasional · medium severityTypical onset: 70,000-110,000 mi
Symptoms: Rattling sound at idle or light throttle (sounds like loose heat shield), Loss of boost pressure and power, Check engine light with P0234 overboost or P0299 underboost codes, Excessive black smoke under acceleration, Turbo whine or whistling
Fix: The wastegate actuator rods wear and rattle, eventually sticking or failing completely. Early on it's just annoying noise; later you lose boost control. Each turbo replacement is 6-8 hours labor due to tight engine bay access. Often both turbos are replaced simultaneously since they age together. This was addressed with a recall on some model years but 2017 often falls outside that window.
Estimated cost: $2,200-4,000
Hard pass on the EcoBoost unless you find one with full engine replacement history and verified PTU/transmission maintenance—the 3.7L V6 version is a safer used buy but still watch that PTU and trans cooler religiously.
AI-assisted summary drawn from NHTSA recall data, our labor-times database, and platform knowledge. Not a substitute for a pre-purchase inspection on a specific vehicle.