Clues To Chilly Problems With Your Climate Control System

Your vehicle’s climate control system can turn a holiday drive into a joyful adventure or a nightmare before Christmas. It all depends on several unrelated factors that could prevent air from flowing to all your passengers the way it should.

Moisture inside the cabin creates visibility problems, humidity and a chill. That can happen no matter where you live--in the subtropical climates of Florida and Texas as well as the frigid environs of Chicago.

Is your family traveling to mountainous regions or icy locations for the holidays? Get your climate control system inspected before packing the vehicle.

Mark Taylor, executive director of the National Automotive Radiator Service Association, suggested drivers watch for common heating and cooling problems.

“If your heater core could be malfunctioning, your defrosters won’t be working,” he said, explaining a faulty system inhibits its ability to eliminate ice and fog from the windshield. “The core could also be blowing fog/smoke into your vehicle's cabin.

“If either of these things occur, you need to be checked right away by taking your vehicle to your mechanic promptly.”

Taylor outlined some common issues with climate control systems that typically show up in winter months:

Low level of radiator solution. This is one of the most common causes of inefficient climate control systems. The solution diminishes over time through evaporation, and the fluid should be checked at least twice a year--in summer and winter. A good rule of thumb: Have radiator fluid checked at every oil change.

Coolant/antifreeze solution may need to be replaced. The solution varies by where you live and how you drive. Ask your service advisor for a recommendation based on your holiday driving plans.

Thermostat not operating properly. The thermostat is a simple, but critical valve designed to block coolant from circulating through the cooling system when an engine is cold, allowing the engine to heat up and reach operating temperature quickly.

Plugged heater core. Heat from the circulating coolant is transferred to the heater core. The blower fan pushes air over the heater core (similar to a small radiator), removing heat from the coolant. This heat is used to warm up the passenger compartment and defrost the windshield.

Heater control valve problems. Some vehicles have a heater control valve which opens to allow hot coolant to flow through the heater core.

Lukewarm or cool air on heat settings. This could occur if the control valve is stuck closed, leaking or disconnected from the heater control.

“A stuck thermostat will cause the car to overheat,” Taylor said. “For a thermostat to be the culprit, it has to be stuck open, which means the vehicle doesn’t get to operating temperature.

“Your mechanic should be able to detect it easily and come up with a solution rather quickly.”

Look for the following telltale signs your climate control system needs an inspection:

• Vehicle does not produce warm air the way it used to.
• Cabin takes a long time to heat up.
• Windows fog up frequently or the system takes a long time to remove it.
• There’s a noticeable reduction in air flow from vents.
• Odors coming out of air vents when you turn on the climate control system.
• Coolant level keeps dropping in the overflow tank.
• Vehicle temperature gauge shows the vehicle is running hotter than usual.