My car is about 11 years old now. The inside of the cabin is starting to get a little loud. I don't have the extreme whistle from the door but you can feel the air coming through. My question does the weather striping get old after a while that its better to replace it?

 

well, If you think its needs replaced then go ahead and replace it.

Im sure weather stripping can get brittle after 11 years..

 

If you treat the weather stripping with leather and vinyl conditioner it helps keep it soft and seals better. Make it part of your detailing/cleaning process.

 

i have also read to use tire shine on the weatherstripping. Basically conditions it/cleans.

 

If you think your weatherstrip is leaking and it apears to be in descent condition maybe not new try this: Turn your blower on with all the windows up and doors closed, get a stethoscope or hose and run It the hose (while up to your ear) around all the windows, doors, etc and mark with chalk or tape everywhere you heard air leaking! Then place a bead of window sealer (it's like sticky playdough & it's made for windsheilds, etc) behind the weatherstrip at those leaking areas you found until no more air can be heard leaking out! You can find these stuff at auto part stores!