An air cleaner suitable for use with a heavy-duty vehicle includes a cylindrical body that can be mounted to the vehicle so that the body is exposed to an air stream when the vehicle moves in a forward direction. The air cleaner has a boattail, which includes a fin attached to a rear portion of the body. The fin has a vertical orientation and extends in a substantially rearward direction from the body. When the vehicle moves in a forward direction, the boattail reduces the amount of low-pressure air located behind the air cleaner.