The 1991 Chrysler Imperial represents the final year of Chrysler's flagship luxury sedan, built on the Y-body platform with the 3.8L V6. While luxurious for its era, these cars suffer from catastrophic engine failures and transmission cooling issues that can destroy an otherwise solid vehicle.
3.8L V6 Catastrophic Engine Failure (Crankshaft/Bearing Failure)
Common · high severityTypical onset: 80,000-150,000 mi
Symptoms: Severe knocking or rattling from bottom end, especially on cold start, Sudden loss of oil pressure with warning light, Metallic debris in oil during changes, Engine seizure or rod thrown through block in worst cases
Fix: The 3.8L suffers from inadequate crankshaft oiling and weak main/rod bearings. Repair requires complete engine rebuild with upgraded bearings or replacement short block. Expect 18-24 labor hours for removal, rebuild, and reinstallation. Many owners opt for used engine swaps given vehicle value.
Estimated cost: $3,500-6,500
Transmission Oil Cooler Failure and Cross-Contamination
Common · high severityTypical onset: 60,000-120,000 mi
Symptoms: Pink or milky transmission fluid indicating coolant mixing, Erratic shifting or slipping after cooler fails, Engine overheating combined with transmission issues, Strawberry milkshake appearance in radiator or transmission pan
Fix: The internal transmission cooler in the radiator fails, allowing coolant into ATF and destroying the A-604 4-speed automatic. Requires radiator replacement, complete transmission flush or rebuild, and all cooler lines. If caught early (just cooler), 6-8 hours labor. If transmission damaged, add rebuild at 12-16 hours.
Estimated cost: $800-4,200
Head Gasket Failure (Both Heads)
Occasional · high severityTypical onset: 90,000-140,000 mi
Symptoms: White smoke from exhaust, especially on startup, Coolant loss with no visible leaks, Rough idle and misfiring, Milky oil or oil in coolant reservoir, Overheating under load
Fix: The 3.8L V6 develops head gasket leaks from inadequate clamping force and age-related gasket degradation. Both heads should be done simultaneously. Requires head removal, resurfacing, and new gaskets. 14-18 labor hours. Often discovered during diagnosis of overheating or coolant loss.
Estimated cost: $2,200-3,800
A-604 Transmission Internal Failures
Common · high severityTypical onset: 70,000-130,000 mi
Symptoms: Harsh or delayed engagement from Park to Drive/Reverse, Slipping between gears, especially 2nd-3rd shift, No movement in any gear (complete failure), Transmission fluid burnt smell and dark color, Check Engine light with transmission codes
Fix: The Ultradrive A-604 transmission is notoriously fragile with weak solenoid packs, valve body issues, and clutch pack failures. Rebuild requires 10-14 hours labor. Many shops recommend replacement with remanufactured unit due to high internal failure rate even after rebuild. Preventive fluid changes every 30k barely extend life.
Estimated cost: $2,800-4,500
ABS Pump/Module Failure (Bendix-10 System)
Occasional · medium severityTypical onset: null
Symptoms: ABS warning light illuminated continuously, Pulsating brake pedal during normal stops (not just ABS events), Loss of ABS function with normal braking retained, Clicking or buzzing from ABS pump under hood
Fix: The Bendix-10 ABS system pump motor and hydraulic assembly fails from age and moisture intrusion. Replacement requires bleeding entire system. 3-5 labor hours. Units are increasingly scarce; many owners simply disable ABS and live with warning light rather than pay for used/rebuilt modules of questionable reliability.
Estimated cost: $800-1,800
Power Seat Motor and Track Failures
Occasional · low severityTypical onset: null
Symptoms: Power seat stuck in one position, won't move, Grinding noise from seat motors when adjusting, Intermittent operation, works sometimes but not others, Seat tilts or lists to one side
Fix: The complex 8-way power seat mechanisms fail from worn gears and seized tracks. Individual motors can be replaced (2-3 hours per seat) but often the entire track assembly needs rebuilding or replacement. Front seats only; rear seats are manual. Parts availability is poor, often requiring junkyard sourcing.
Estimated cost: $400-1,200
Avoid unless free or under $1,000—the 3.8L and A-604 are ticking time bombs that will cost more to fix than the car's worth, and parts availability is becoming critical.
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.