By DAVID COLBURN

News editor

There’s been an uptick in business lately at Webster Auto Repair in Marion that’s inversely related to the downturn in temperatures: heater problems.

“When it starts getting this cold, problems start showing up fast,” owner Barry Allen said.

Extremely cold temperatures can expose problems that may be months old as heaters are taxed to the maximum, he said.

Proper heat levels aren’t just a matter of personal comfort. Poorly-performing heating systems can be safety hazards.

“If you can’t keep your windshield defrosted and there’s a little bit of freezing rain, you won’t be able to see where you’re going,” Allen said.

Condensation also may form and freeze on the inside of the windshield and door windows.

“You can scrape it off, but it’s building back up when you’re going down the road,” Allen said.

Checking for the source of a heating problem begins with something as simple as taking off a radiator cap. Low antifreeze levels may be an issue.

“It doesn’t have enough to push up through the heater core,” Allen said. “You don’t see engine overheating because the outside temperature is keeping the engine cooler.”

Another frequent problem sits away from the heater, too.

“One of the big things that happens is that a thermostat will stick open so your engine temperature doesn’t come up to where it’s supposed to, so your heater doesn’t work as well,” Allen said.

The two most common problems Allen encounters are bad thermostats and clogged heater cores.

“If the temperature of the engine is coming up, check the heater hoses to see if they’re both hot,” he said. “A lot of times the coolant gets bad and the heater core gets plugged up.”

Antifreeze that’s deteriorating becomes corrosive and can cause heater cores to clog. A less common but possible culprit is stop leak poured into the cooling system.

“It will stop the leak, but it decreases the efficiency of the heater,” Allen said.

Flushing the heater core to restore coolant flow and heat is a common fix that some do-it-yourselfers can tackle.

“It depends on their skill level,” Allen said. “We do it quite a bit. It depends on if you have a way to pressurize what you’re putting through there. You don’t want to put too much pressure or you can damage the heater core and you can have a leak.”

If the core is heavily plugged or damaged, replacing it can be an intensive chore.

“It’s fairly difficult,” Allen said. “Some cars you have to take the entire dash out. It’s pretty labor intensive.”

Older cars had heater control valves in the engine compartment that could go bad, but those have been eliminated in most new cars, Allen said. Instead, small doors on the heating and cooling air ducts inside the passenger compartment move to regulate heat. Door actuators can go bad, compromising the flow of warm air.

The best way to deal with heater problems is prevention, Allen said, by making sure the cooling system is always filled with good antifreeze.

Some antifreezes are rated for up to 100,000 miles, but Allen’s experience is that they don’t last that long.

“Antifreeze can look fine, but the pH level can be really high in it, and that’s what begins deteriorating your system,” he said.

Many people put off changing antifreeze because of the cost.

“What we run into with a lot of people is that maintenance has been neglected because of the expense,” Allen said. “They know that that stuff needs to be maintained. It’s for lack of funds that they just try to get by. It’s a lot cheaper just to flush the antifreeze out.”