回複：求助，Nissan Sentra CYLINDER 之一 Misfire，不修有啥後果。

head gasket leaking is a serious issue, if you don't fix it, your engine is quickly (within months) reaching to grave land.

to detect head gasket leaking is easy, two symptoms: (1) milky oil (coolant gets into oil), and (2) oil trace on top of coolant (see it under sunshine). As simple as that, no ambiguity. dealer should know right away.

If you see any one of above two symptoms, let them fix it right away, don't drive it (tow to dealer). (if you change oil, you can buy time for a few days)