The Mégane II Owners' Club

Hiya.

The passanger side on my Megane II CC has always been a lot noisier than the drivers side. It's as if the wind is always coming in, So..... Is it worth trying to replace the seal, and is it something that's do-able at home (I'm assuming it's the seal that goes around the window, when up

Mine are quite noisy too under certain conditions chances are it will be the seal on the rear quarter lite where it sits against the door window.
You may find the rear quarter lite needs a slight adjustment if it isn't that then the door glass might be a little low there are two 10mm bolts behind rubber grommets on the underside of the door you can use these to slightly adjust the glass.

A good trick is electric tape, stick it on the glass and rubber seal to seal the window to rubber gap,l then drive it it can help pin point wind leaks on seals by pulling bits of tape off until you hear wind noise.

Bear in mind they r quite noisy cars the window seals are not the best neither is the sound insulation.

Mine is an 04 car so its thirteen years old now yet not changed any door seals its its not damaged then try adjustment first

Hope this helps a little.