engine noise

You need to see a BMW specialist. It could be a failing alternator or water pump, or a bad belt or worse, but have given me no good information in your question. A person would have to see the car and hear the noise to be sure. Here's a directory link for you, but I don't know if it covers PR so you may have to find a guy on your own. http://repairpal.com/bmw-repair-in-guaynabo-puerto-rico