Cold, winter mornings have a way of creeping up on you each year. The days grow shorter. You wake up and start your day before the sun rises. As you rush to your car, your thoughts drift over your day ahead: meetings, a deadline for a project, a few phone calls you need to make. You don’t think much about how cold your car is; it’ll warm up quickly. 

But it doesn’t. A few miles down the road, you start noticing how cold it is. Your car’s heater isn’t working right, and it’s blowing cold air all around you. You notice a few snowflakes starting to fall, and you shiver in response. 

Now what? 

How a car’s heating system works

Your car’s heating system includes a few basic components: heater core, blower fan, heater control valve, heater hoses, the ventilation system, and control panel located inside the car. 

Heat is created by the engine, and needs someplace to go. Most of that is filtered out through the exhaust system, with the rest remaining in the engine, transferred to the coolant. 

When your vehicle reaches operating temperature, the thermostat opens up and allows coolant to circulate throughout the system. It removes any heat from the engine, sending it into the radiator and the heater core. From there, it distributes the heat into your cabin. You control the temperature, ensuring the passenger section is as warm or cool as you desire. 

For the heater to work properly, the cooling system needs to be in good working condition. That means the correct mix of coolant and water, with proper coolant levels and no leaks in the system. The thermostat should open and close at the proper temperature levels, with the water pump circulating coolant through the engine, radiator, and heating core as needed. If this system works well, your heater will be there to provide conditioned air at the levels you desire. 

When your car heater isn’t working, there’s something wrong in the system. 

Low coolant levels

One of the first things to check is also one of the most common reasons for a heater to stop working. If the coolant levels are low within the system, it can’t circulate properly through the system. In optimal working conditions, coolant levels won’t change. If there is a leak, it can occur anywhere within the system: cracked coolant tank, broken gasket, faulty hose, etc. 

If the heater doesn’t warm up and start blowing heated air within ten minutes, the coolant might be too low to circulate through the heater core. While you may feel it inside the cabin with little to no heat, your car’s engine feels it in different ways. Without proper coolant levels, the engine might overheat, which is an expensive repair to fix. 

Coolant isn’t like other fluids. It won’t evaporate, and adding more into the system won’t fix the problem. You’ll have to find the root cause and fix the problem at the source.  

Malfunctioning thermostat

Your car’s thermostat is a valve that opens and closes to regulate coolant flow into the engine and radiator. While it’s a simplistic device, it’s vital to keeping your engine running at the proper temperature. 

A malfunctioning thermostat is often stuck in the open or closed position. If it’s stuck in the open position, it allows too much coolant to flow, preventing the car from reaching optimal operating temperature. A thermostat stuck in the closed position won’t allow coolant to circulate, which stops the heat from flowing properly throughout the system. Both will be noticeable by decreased performance. 

Faulty heater core

The heater core works similarly to the radiator. While the radiator dissipates heat to the surrounding air, the heater core sends heat into the passenger cabin by a blower fan. 

The heater core uses a maze of narrow tubes and fins for proper circulation. If any one of these is blocked or damaged, it reduces the coolant level or flow through the engine’s cooling system. A faulty heater core and low coolant levels often are interchangeable, with one impacting the other. Two easy ways to tell if your heater core has been compromised include windows that easily fog up, or a sweet-smelling scent lingering inside your car. Both are signs you should schedule a maintenance visit soon. 

Faulty blower fan

When you turn up the heat on the dashboard panel inside your car, the heater core captures warm air from the coolant and transfers it into the cabin as a warm air supply. The blower fan makes it possible for ventilation of the warm air from the heater core, pushing it out through the vents. If the blower fan isn’t working, there will be no way to transfer the warmed air supply out through the vents. 

The blower fan can malfunction for a variety of reasons. It could be a blown fuse, or damage to the internal components of the blower fan. If you barely feel a breeze no matter how high you turn up the heat, chances are it’s a problem with the blower fan. 

Other problems

Of course, the above are some of the most popular reasons why your car’s heating system might not be working. But cars today are built with more than 10,000 parts. If a wire frays, a hose cracks, a part breaks, or fluid stops flowing, it will cause problems throughout the system. 

The only way to get to the root of the problem is with a thorough diagnostics test. 

Get cozy once again – schedule a maintenance visit today

Colorado weather is unpredictable at best. While it might be sunny and warm enough for the windows to be rolled down today, the snow could be flying by the time you rise for work tomorrow. 

It’s hard to enjoy the ride in, or be stuck in traffic if you’re shivering inside a cold car. A heating system not operating correctly is a sign of a bigger problem. 

An inspection will help locate the problem, allowing mechanics to get to the broken or faulty piece quickly, and have you back on the road in no time. 

Have you ever experienced a car heater not operating correctly?