I am having a difficult time researching this issue because it is difficult to search for things like 'diesel sound'

So I am hoping that someone may recognize this immediately and send me in the right direction to do my research.
My 2003 X5 3.0i has started making a putt-putt sound from under the passenger side. When I roll the windows down I hear it more from the passenger side than from the drivers side. Another way of describing it is similar to a diesel engine sound. It is not a particularly bad sound, but I don't think that it is running correctly. My guess would be that there is a leak in the exhaust somewhere.
Is there a common place for the X5 3.0i to have a leak in the exhaust up by the front?
Thank you.