An air deflector is a device mounted on a vehicle to alter the flow of air. Typically attached to the hood, the air deflector changes the flow of air traveling over the nose of the vehicle so that it flows over the windshield and does not make contact with the glass. This prevents bugs from hitting the windshield and creating a difficult-to-remove mess. Some air deflector installations mount the deflector over the rear window of the vehicle. Often used in minivans, station wagons and sport utility vehicles (SUVs), the deflector alters the air flow over the rear of the vehicle and keeps dirt and debris off of the rear glass.
Occasionally referred to as a bug deflector due to the results of its actions, an air deflector does not always produce positive results. In rainy situations, the deflector often alters wind flow over the front of the vehicle so effectively that it prevents the windshield wipers from operating as intended. As the altered air flow travels up and over the nose of the vehicle, it often sucks the windshield wipers up and off of the windshield. This creates a dangerous vision situation that can hinder the operator's ability to clearly see the road in front of the vehicle.
One solution to this problem is often seen on large tractor trailer rigs. When possible, positioning the air deflector away from the leading edge of the vehicle's hood and slightly closer to the windshield often cures the problem. It may take several attempts to discover the proper location where the air deflector will avoid creating the windshield wiper interruption. When attempting to find the correct mounting position for the air deflector, the use of double-sided tape to temporarily mount the deflector brackets will prevent drilling several mounting holes in the vehicle's hood.
When mounting an air deflector on the rear of a vehicle, it is important to position the deflector squarely on the center. Carefully measuring each side of the deflector will allow it to be positioned evenly over the rear window of the vehicle. By altering the flow of air over the rear of the vehicle, the turbulent air pocket behind the vehicle is moved farther away from the rear window glass. This eliminates the majority of dirt being kicked up by the vehicle as it travels on the roadway and keeps it from sticking to the rear glass.