I have a 2008 Cooper S, and from the time I got it the vacuum pump has been rattling. I verified this by unplugged one of the hoses that went to the pump on the top (there is a video on this somewhere) and the sound goes away. From what I understood it was safe to run the car with the pump rattling, as long as the oil was where it should be, and mine is always there (I check it weekly). However, now I am reading that the pump needs to be replaced because to can destroy the engine? How accurate is that, and how worried should I be about that rattle? I have always been ignoring the sound because I was under the impression that it is safe to run the car with it.

 

If you know your vac pump is making noise I'd replace it asap as we have seen them fail and it takes out the whole engine. So the cost of the pump is a fraction compared to the engine and not worth risking it.
https://www.waymotorworks.com/vacuum...5-r56-r57.html

 

http://www.rmeuropean.com/Products/1...244-V6336.aspx

 

Once the vacuum pump fails you do not get a second chance. Change it now.

 

If the vacuum pump fails and locks up it can break the end off of the camshaft and bam, your engine is gone.