Q: I have a 1997 Chevy van and my air conditioner works fine as long as the vehicle is moving. But when I stop at a traffic light, the AC stops working; I feel warm, humid air coming through the vents. What can the problem be?
Salt Lake City, Utah
A: Most likely, the problem is that the amount of air passing through the condenser is too small to cool your van when it's stopped. The condenser is the part of the air-conditioning system that transfers heat from the cabin to outside the vehicle. Condensers must maintain good airflow to do their job. In front-wheel-drive vehicles, condenser airflow is supplemented by an electric cooling fan. In rear-wheel-drive vehicles, the air-conditioning system takes advantage of the engine's cooling fan. So the problem may be due to a worn fan clutch (rear-wheel-drive vehicles only) or an inoperative electric fan in front of or behind the radiator (in either front- or rear-wheel drives). Vans have large interior spaces and require efficient air-conditioning systems to maintain a comfortable temperature. Because the AC does cool your van when it's moving, every other component of the system is probably working.
Q: I have an annoying problem with my '94 Mazda 626. Every time I drive it, a whistling sound comes from the driver's-side window. It doesn't matter whether the window is up or down. I've had a mechanic check it, but he can't locate the problem. What's my next step?
A: Whistling is often caused by an air gap between the window and the window frame or between the frame and the vehicle body. Test for an air gap by closing the window or door with a dollar bill in position so it's trapped by the rubber seal when the window or door is closed. If the seal is tight, you'll feel at least a slight drag as you pull the bill out. Spots where the bill slides out without resistance may cause the whistle. Most body shops should be able to adjust the door or the window, or both, to eliminate the gap and whistle.
Please send car problems to Your Car, VIA, 150 Van Ness Avenue, San Francisco, CA 94102. Email: email@example.com. Questions will be answered only in the magazine.
This article was first published in January 2004. Some facts may have aged gracelessly. Please call ahead to verify information.