Having your car’s heater suddenly stop working in the middle of a long drive in the winter can be very annoying. More than that, it can sometimes be outright life-threatening.
What can you do in such a situation, however? And even more importantly, how can you prevent it from happening? Heating not working in cars is one of those things you’d really want to avoid and just never have to deal with on the road.
There are several main reasons why you might be left with no heat in cars and all of them can be checked and dealt with before leaving your garage. Heating stopped working in cars is one of the most common complaints mechanics receive and these are the symptoms people usually experience:
- Heater blows cold air one side hot other
- Car heater blowing cold air and overheating
- There’s fog inside your car
- There’s a sweet fruity odor coming out of the vents
- Car heater blowing cold air when stopped
- Your car’s engine is overheating
- Car heater not blowing air at all
Each of those symptoms can be caused by various malfunctions that often overlap. So, my car heater is not working and is blowing cold air – what might be causing it? Here are the main reasons for all the malfunctions above:
Your engine is running out of coolant
Coolant is typically made of 50% water and 50% antifreeze. Its main purpose is to cool the engine down during the hot summer months. In the winter, however, it’s extracted from the engine and brought into the heater core which is blowing warm air into your car. Once the engine picks up power, it heats the coolant and technically turns it into a “heatant” – the heated up coolant is what provides heat to your car’s interior.
This is why you usually have to wait a little for the car to get heated up – the engine needs to work a little before it picks up enough temperature to heat up the coolant. However, if your car is low on coolant, there won’t be enough of it to send to the heater core and warm up your car’s interior.
So, what do you need to do? Ironically, you need to add more coolant to heat your car.
Problems with the heater core
There are myriad problems that can occur in the heater core of your car, each capable of interfering with the heating. The main three to check for are:
- The coolant isn’t getting to the core efficiently
- The air from the blower isn’t obstructed and can’t reach the vent
- There’s a clogged tube inside the core itself
Either of these problems can interfere with the operation of the system. In essence, a car heater works like a compact radiator – you have to inspect every component to make sure that things are working properly. The heater core is typically situated immediately behind the back of the car’s dashboard. So, if your car’s coolant is fine, this is usually the second thing you should check out.
A malfunctioning thermostat
As with home heating systems, the thermostat should be one of the first things you check whenever there’s a problem. The main symptom of a dysfunctional thermostat is if the thermostat gauge remains stationary even after your engine has warmed up.
It’s the thermostat’s job to signal the car that the engine is warm and coolant needs to be sent to the heater core. If the thermostat isn’t doing its job, the coolant won’t reach the heater core and the air you get from the vents will still be cold.
Fortunately, thermostats are relatively cheap so getting a new device and replacing the old one should be relatively easy even if you haven’t done it before.
The heating controls are clogged or broken
Probably the simplest problem that can occur in the whole system is in the controls. If you’ve been using a heating system for several years and you’re not in the habit of cleaning your dashboard, the heating controls can easily get gummed down and blocked. So, even if your coolant and heater are working at 100%, you can still have an inoperational heating system.
Alternatively, you may be having problems with the heater control valve. This component is located under your car’s hood and it’s what switches the heat on and off when you give it the right signal. If your car keeps pumping cool air in, no matter what you’re doing, this can be the reason why.
Last but definitely not least, you should also look for water leakage. Unfortunately, such water leaks can occur almost anywhere in the system – the water pump, the radiator, or any of the hoses. If your car’s heater isn’t working properly and you’ve checked all other possible causes, inspect the system for water leaks too.
Does any of these issues necessitate professional help?
An experienced driver should know their car well enough to easily check for all five of these problems and fix them when necessary. You should also perform regular checkups on all these systems and the rest of your car’s inner workings to prevent any problems from arising in more inconvenient times.
That being said, you should also go through annual professional checkups to make sure everything is running smoothly. And if heating problems do occur at any time and you can’t figure or fix the cause, definitely go to a professional mechanic and don’t postpone dealing with the problem.
Not only can you find yourself in a position where you need your car’s heating to work well, but some of the problems can also lead up to other bigger, more dangerous issues too.