I changed the in cabin microfilter with a Nissan OEM replacement a few weeks ago in my 2k3, since then there has been a whistling noise when the climate control fan is on. It's not to bad when the fan is on '1' but on 2,3 and 4 it gets progressivly more annoying. Obviously the first step would be to pull the filter out, but what should I look for? Is there something I should do when I put it in to prevent the whistling? It seems like there is only one way it can go in