NHTSA Complaint #11695577 — 2018 CHRYSLER PACIFICA

2018 Chrysler Pacifica, 3.6L V6, approx. 66,476 miles. The vehicle began losing coolant with no visible external leaks. When cold, opening the coolant reservoir cap releases a strong hiss of pressure and coolant flows back into the tank. The check engine light appeared, first showing a cylinder misfire (resolved after spark plug replacement), then later a slow EGR leak code. Over the next several weeks, the coolant level continued dropping and the reservoir remained pressurized even when cold. Vehicle was inspected by Waxahachie Dodge Chrysler Jeep (RO #490099, Sept 2025). Technician performed a combustion gas test and confirmed exhaust gases are present in the coolant system. No external leaks were found. Diagnosis: failed head gasket allowing combustion gases into the cooling system and coolant to burn in cylinders. The technician stated overheating or warpage may have opened a path at the head gasket but found no external signs of overheating. This condition poses a safety risk—coolant loss and trapped pressure can cause sudden overheating, engine stall, or hydrolock while driving, potentially leading to loss of power or a crash hazard. The issue was confirmed by a Chrysler dealer and documented in the repair order. The vehicle remains available for inspection. Prior to failure, symptoms included the check engine light, rough running, and repeated coolant loss. There were no visible leaks or overheating messages. Manufacturer was contacted but declined assistance; dealer verified diagnosis and estimate for repair (~$7,800).