What are the symptoms of a clogged heater core?

Is your car feeling frosty during winter?

Have you noticed your car is struggling to supply you with warm air on those colder days?

This could be due to a clogged or failed heater core, which is responsible for dispensing warm air into the cabin via the blower motor. When you turn the heat on, the heater core tubes receive hot coolant from the engine and the blower motor pushes air across the core fins into the interior of the car. It can be used to warm you up and also to defog or defrost the windscreen.

Symptoms of a clogged heater core

Without a properly functioning heater core, visibility can be compromised and can make for an uncomfortable (and dangerous) ride during the cold months. Sound familiar? Driving with a failed core could lead to bigger problems down the track, especially if the cause is leaking coolant. Read more to find out how you can tell if something might be awry with your heating.

Natrad offers a nationwide warranty on new air conditioning parts fitted to your car. Need a new heater core? Get in touch today.

Heater core functionality

Before we diagnose the problem, it’s important to understand how it all works. The heater core may be a part of the air conditioning system, but it relies on using hot circulating engine coolant to deliver heated air into the cabin or for defogging.

The core itself is like a tiny radiator. Similarly, it has tubes that coolant passes through and fins, where air passes across. It uses the heat from the coolant to warm the air that will then be blown into the cabin of the car.

Some vehicle systems have a valve that regulates when coolant should flow to the heater core. Others have coolant circulating past it constantly and simply open a door or flap to allow airflow into the cabin. The air is pushed into the cabin by the blower motor, which activates when the air conditioning system turns on.

If heating is desired, the air is directed through the heater core. If cooling is desired, the air is directed through the evaporator instead which is cooled by refrigerant.

Heater core failure symptoms

It will be pretty obvious if you are not receiving warm air inside the cabin or the defogging function isn’t working well. This is the first sign that something may have failed and clogging isn’t the only culprit either. Have you noticed something isn’t quite right? Take a look at these signs and see if they apply to you.

Key signs to look out for:

• Weak or no airflow
• Cold air (not warm) coming through the vents when the heater is on
• Coolant leakage visible inside the cabin or a damp smell

What do these signs mean? A noticeable difference in airflow could indicate that the heater core fins have been clogged and are restricting airflow. A coolant smell or visible coolant leakage inside the car is a bit more sinister. This is likely due to a hole in the core somewhere and the coolant is escaping into the cabin. This is typically where heater cores are situated. It may need to be replaced in order to get the system working although sometimes sealing the leak is possible.

Important tip: coolant leakage inside the cabin can be dangerous for several reasons. Liquid near or on the pedals can make them slippery, and the liquid itself can encourage mould or rust which can then corrode the floor of your car.

If the cause of the problem is a leak, your car may be losing coolant slowly. If you notice a low coolant level but can’t locate the source of the leak, it could be escaping into the cabin of the car. Coolant loss will cause engine overheating which is not good for many parts inside the system!

What now?

If you’ve noticed any of the above symptoms, then it’s time to take action. Talk to a knowledgeable technician at your local Natrad store to properly diagnose the problem. The fault may be obvious or some deeper digging might be needed, but whatever repair is required, Natrad can help.

For new heater cores and any other part to fix your air conditioning system, Natrad is your one-stop shop. For fast service and a 12 month warranty, contact us today.