The 2018 Chrysler 300 is a solid full-size sedan riding on the proven LX/LD platform, but the ZF 8-speed automatic and certain V8 engine issues (particularly the 5.7L Hemi) create expensive headaches around the 80,000-mile mark. The 3.6L Pentastar is generally more reliable, though not immune to problems.
ZF 8HP Transmission Output Shaft Bearing Failure
Occasional · high severityTypical onset: 75,000-110,000 mi
Symptoms: Grinding or whining noise from transmission during acceleration, Metallic debris in transmission fluid during service, Loss of certain gears or complete transmission failure if bearing disintegrates
Fix: Requires transmission removal and teardown to replace output shaft bearing and inspect for collateral damage. If debris contaminated valve body or clutches, full rebuild needed. 8-12 labor hours for bearing replacement alone, 16-22 hours for full rebuild.
Estimated cost: $2,800-5,500
5.7L Hemi Multi-Displacement System (MDS) Lifter and Camshaft Failure
Common · high severityTypical onset: 60,000-100,000 mi
Symptoms: Ticking or tapping noise from engine that worsens with mileage, Check engine light with misfire codes (P0300-P0308), Rough idle or stumbling on acceleration, Metal shavings in oil during changes
Fix: MDS lifters collapse or seize, scoring the camshaft lobes. Requires both camshafts, all 16 lifters, pushrods inspection, and often cylinder head work if cam bearings damaged. 18-24 labor hours if heads stay on, 28-35 hours if heads need machining or replacement.
Estimated cost: $4,500-8,000
Transmission Oil Cooler Line Corrosion and Leaks
Common · medium severityTypical onset: 70,000-120,000 mi
Symptoms: Transmission fluid puddles under vehicle, usually front-center, Low transmission fluid warning on dashboard, Burnt smell or slipping if fluid level drops significantly, Visible rust or corrosion on cooler lines at radiator connection
Fix: Steel cooler lines rust through where they connect to radiator or run along frame. Replacement requires both lines typically, plus fluid flush. 2-3.5 labor hours depending on accessibility and whether radiator needs partial removal.
Estimated cost: $600-1,200
3.6L Pentastar Cylinder Head Gasket Failure (Left Bank)
Occasional · high severityTypical onset: 80,000-130,000 mi
Symptoms: Coolant loss with no visible external leaks, White smoke from exhaust on cold starts, Rough running or misfire on cylinders 1, 3, or 5, Milky oil or oil in coolant reservoir
Fix: Left (driver side) head gasket prone to failure between cylinders or into coolant jacket. Requires head removal, resurfacing, new gasket, and typically timing chain component inspection while apart. 12-16 labor hours.
Estimated cost: $2,200-3,800
TIPM (Totally Integrated Power Module) Failures
Occasional · medium severitySymptoms: Intermittent no-start conditions (starter doesn't engage), Fuel pump not priming on key-on, Random electrical gremlins (windows, wipers, gauges acting erratically), Multiple fault codes across different systems with no clear pattern
Fix: The TIPM (under hood fuse box/computer) develops internal relay or circuit failures. Replacement requires new module plus programming. Some independent shops offer TIPM repair services for less. 1.5-2.5 labor hours for replacement plus programming time.
Estimated cost: $800-1,800
Engine Mount Failure (Front and Transmission Mount)
Common · low severityTypical onset: 60,000-90,000 mi
Symptoms: Clunking noise when shifting from Park to Drive or Reverse, Excessive vibration at idle, especially with AC on, Visible engine movement when revving in Park, Torn rubber visible on mount inspection
Fix: Hydraulic engine mounts (especially front) and transmission mount wear from V6/V8 torque. Front mount is 2-3 hours, transmission mount is 1.5-2 hours. Often done together.
Estimated cost: $500-900
Fuel Filter Clogging (Hemi Models)
Occasional · medium severityTypical onset: 80,000-110,000 mi
Symptoms: Hard starting after sitting overnight, Loss of power under hard acceleration, Engine stumbling or surging at highway speeds, Fuel pump running louder than normal
Fix: In-tank fuel filter/pump assembly gets contaminated, especially if fuel quality has been poor. Requires tank drop and pump module replacement. 3-4 labor hours.
Estimated cost: $700-1,200
The 3.6L V6 is a safer used buy; avoid 5.7L Hemi models unless full cam/lifter service history is documented—otherwise budget $5K for eventual engine work.
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.