BMW question

[STRteg]

I'd say bad thermostat and its building up to much pressure. I think the thermostat and housing are built all together if i'm not mistaking and are purchased as one piece (I know a lot of bmw's are like that anyways) and most of the time advance auto parts can have it next day if ordered early enough. Just talk to someone who know what they are talking about. That's where I would personally start anyways.

Thanks for the input man,anyone else?