Did a basic service on my wife's '56 plate A4 yesterday. Popped the box open to replace the air filter and was surprised how much detritus was in there. Had the car about six months so first time I'd been in the air box. Then I noticed a pre air filter filter in the ducting that was somewhat clogged....
After Cleaning.....

Before cleaning....
.
Can't believe the engine was running! It's a 3.0tdi and it was running fine but seems to be smoother now!
After Cleaning.....

Before cleaning....
.Can't believe the engine was running! It's a 3.0tdi and it was running fine but seems to be smoother now!