CCVs on 2006 X5 4.4 are on the valve covers, there are 2 total. The video link above is for a M62 engine, I'm sure you have the N62. Similar looking diaphragm as as video, but smaller and 1 on each valve cover. Simple to replace, diaphragm is under a removable round cap, about $10 each. But... I'm guessing at 120k miles it's valve seals, not an easy repair. Would try replacing the CCVs first to rule that out.