NHTSA Complaint #11620420 — 2020 CHRYSLER PACIFICA

Car started to rock and the engine light came on with a cylinder 3 misfire code (P0303). We replaced the spark plug and coil on cylinder 3 and the issue resolved temporarily. About 48 hours later the rocking and engine light came back on with the same error code. We swapped the spark plug and coil on cylinder 3 for those on cylinder 1. The check engine light turned off but we would still get the rocking intermittently. We also noticed the coolant level was low and there are water vapor coming from the exhaust in the morning when starting the engine. The engine temperature never got hot that we noticed. We refilled the coolant level but it would slowly drop, and we felt there may be a leak or, with the cylinder 3 misfire, there may be a blown head gasket. We tried a K-seal coolant leak repair. This stopped the coolant leak and rocking for a few weeks, but the leak and engine rocking started to return. We took it to an auto-body shop and, after flushing the line, they checked the engine head gasket which had a leak on cylinder 3 (and apparently cylinder 1 was also starting to go bad). This had to be replaced along with a bad radiator fan assembly. After looking online, there have been very similar issues with other Pacifica engine head gaskets, so we decided to file a report.