the vent intakes are the grilles on hood where washer nozzles are , if you lift hood you`ll see another grille panel with twist lock catches , in here you`ll see microfilter and take note of way it`s fitted before removing , once removed you`ll see two ovalled tubes leading to cabin . this stuff is best left alone because all you really need to do is as i previously posted and weasel 56 agreed .

I had to re-read both your and weasel's replies twice, and interestingly enough, neither one of you specifies what the 'product' name is. That would help, no? :D

Actually there's no need to buy anything to solve this problem.
Back in 2006 someone found the logical cure.
http://www.xoutpost.com/x5-e53-forum/14529-c-smells.html

i`m in great britain and product is made by COMMA ,it`s called air conditioning system cleaner odly enough. you can buy stuff at any auto store or bmw parts counter . the link on Quicksilvers reply is not neccessary unless you`re fastidious . oh yeah and go back to weasels post and read product by WINZOR , ok i`m done cos typing making fingers numb and repeating myself making brain numb .:rolleyes: and Quicksilvers link names products suitable for that particular process. I`m adding edit because the method in the link actually cleans by spraying liquid on components to remove mould or mold as some understand it . also know of a quality used car lot where they clean a car cleaner than it has ever been , they remove entire cabin air system and disassemble and clean every part. car interior is disassemled and cleaned if your`e trully fastidious with your car .

Does it make the x5 smell like chlorine after? I had the dealer do this to my x5 and it fixed the ac smell but the x5 smelled like chlorine for a week.

It does have a cleaner type smell afterwards for a lil bit, but it really kills all the musty odor, and any other odor that may be in the cabin. I've used it on a car that had shrimp juice spill on the carpet! It's like a lysol bug bomb your car.

Yea the smell wasn't too strong though. All that matters is that it did work.