Among the most prevalent reliability problems that plagued owners of Cadillacs that had Northstar engines were head gasket failures. They were among the top complaints in its early years since the Northstar engines were first unveiled in 1993. However, Cadillac and GM continued to slowly and steadily fix those head gasket issues throughout the 90s. It's hard to determine precisely when the head gasket problems were fixed for good, but sometime after the 2000s should be a good guess. Many say that the major revision of the Cadillac DeVille for the 2000 model year had fixed the head gasket issue. Meanwhile, others say that it wasn't until minor updates came along in 2002 and 2004 that the Northstar's infamous head gasket problems were solved for good.