I have created a basic car body. Now, I'm trying to get the tires in place. What I am trying to do is to use a cylinder of 10 vertices with an Array modifier at Count: 1 and Relative Offset set to mimic the cylinder on the other side. Then, I am using the Boolean modifier to subtract the cylinder from the car body. However, it produces strange results when I drag my cylinder out after applying.
Car Cube Modifiers:
Car body before applying the Boolean modifier:
.blend file from before applying the Boolean: