Any problem that comes up with your trusted BMW can be disconcerting, but the fact that most issues are harmless if fixed right away should put your mind at ease. A broken radiator cap is an example of a problem that isn’t too severe, but should still be fixed as soon as it’s discovered.

The radiator system as a whole is complex, and the cap is simply a small part of that system. To actually understand the importance of fixing the radiator cap when it breaks, you need to understand what the radiator does and what the cap itself is …