Help needed - E53 3.0i cooling system pressure test

[oldskewel]

Sorry, dumb questions here. If I had the car in front of me I would not need to ask, but I'm trying to help my daughter from 200 miles away.

2001 X5 3.0i

It seems to be leaking coolant from somewhere. I'd like to pressure test it. How exactly does the pressure tester attach to these cars? I've done test on many other cars, so I know how it works, I just don't know what these BMW engineer geniuses did with the radiator cap. Is there one? Where is it (I told you these were dumb questions, but I will apologize again)? Will a standard cooling system pressure tester fit and work as it normally does?

Since I'll be telling my daughter what to do remotely, guesses or close-enough won't work. So please only respond regarding the 3.0, not the V8.

From a quick search on here (difficult with slow internet), it seems the entire cooling system on these cars may have been designed by the same guys that did the window regulators. No problem, I can fix anything, I just need some information. Thanks in advance.