Why Does Your Car Heater Not Work?
In the cold weather, there’s some respite when you sit in the car and turn on the heater. A blast of warm air later, there is a small comfort! Ahhh, small things that we need to keep us happy!
When the car is turned on, the car’s heaters work by making use of the heat in the car’s coolant which circulates around your car’s engine. This is why there’s no warm air just as the car has started, and instead needs a few minutes for the coolant to warm sufficiently.
A thermostat is used for regulating the water circulation that waits until the water has reached a certain temperature, and then, the water can be circulated for cooling the engine, incidentally warming the heater.
To get heat in the car, one needs:
- A working thermostat
- Enough water in your engine
- A cooling system that’s not leaking
- A working heater and heater controls
If there is no warm air in the car no matter how long the car engine has been turned on, there are some checks that can be used for finding the reason behind it. This usually is a relatively cheaper problem to fix.
What You Should Check if Your Car Heater Throws Out Cold Air
- Is the thermostat working?
- Is there enough antifreeze and water in the engine?
- Has the heating system been blocked by an airlock?
- Is there a possibility of a water leak?
- Are the heater controls broken?
Is the thermostat Working?
A thermostat decides whether or not to let the water circulation around the car’s engine. When an engine starts, the thermostat stays off for a small amount of time, thus, giving the water an opportunity to heat up and providing heat for the car’s heater. But, if the thermostat is stuck for some reason, the water might not get a chance to heat up. Hence, even if the water/coolant has been topped up, but there is no heat, a plausible reason for it can be your broken thermostat.
For checking the thermostat, leave the car engine running and then watch dials inside the car. One of the dials indicates water temperature. It might take a while for a properly working thermostat to reach the temperature for giving a reading, somewhere around 10 minutes. If even after that, the engine is hot but the temperature dial says “cold”, then it obvious that thermostat is the reason of why you aren’t getting any heat from the heater.
This can be fixed simply and can be done easily.
Is there enough antifreeze and water in the engine?
A car’s heater makes use of the heat from the circulation of the coolant around the engine. There should also be antifreeze in the coolant mixture, as this not stops corrosion inside the engine but also stops coolant from freezing inside in colder countries. The heater is last in line for coolant as it is higher up as compared to the rest of the cooling system. Hence, if you have no heat, the first thing you should do is check if there is enough coolant in the engine.
This can be done by lifting the car’s bonnet and then looking at its header tank. There is usually a large plastic tank that collects the overflowing coolant from the cooling system’s radiator. The tank has markings of “Max” and “Min” written on it. If the tank is empty, fill it back with ordinary water and antifreeze, however if it is full, it indicates proper levels and hence, it’s alright. If a person isn’t sure about the header tank, then it is better to ask or take your car to a mechanic.
Has the heating system been blocked by an airlock?
Sometimes, even though there’s no issue with the coolant and the thermostat, there still can be no heat due to the flow of water in the cooling and heating system being blocked by dirt or air.
One possible reason is the creation of an air lock in the car’s cooling system. If the system has a bleed screw or a bleed port, you can find it and then fix the air lock yourself. You have to run the car’s engine till the fan starts working. When the fan starts working, look near the radiator for any bleed screw or bleed port. This can be turned by the use of screwdriver. Once it is turned anti-clockwise, a hiss can be heard, which is the sound of air being released.
Is there a possibility of a water leak?
A car engine that keeps on losing water is a big issue and not just because the low water levels will keep the heater from putting out most of the heat. A car not getting proper coolant will get heat up on regular intervals and end up damaging itself. If there is a leakage, you have to find the source for it, which can be leaky radiator, head gasket, or even a split hose. Finding the leakage can be troublesome as even a small hole can push out a lot of water when the system gets under pressure from being driven.
In cold weather, the investigation is relatively easier as when the engine has run for quite some time and is hot enough, the hot water escaping from the leak will turn into steam as it hits the colder weather. You can open the bonnet and look for steam, both inside and outside the car.
If the leaks turn out to be within the radiator, then it can be temporarily fixed with products that work to stop any leaks in the car’s cooling system.
In rare cases, water loss is due to a knackered water pump. Some visible signs of a broken water pump are a constant rough metallic sound which is caused by running engine or when water is trickling along the engine’s side. Since the water pump is a important part of the car engine, if it’s broken, it should be changed ASAP.
However, the worst of all is a leaking head gasket and it means that the engine has lost integrity and the car needs major repairs.
Are the heater controls broken?
Although most problems associated with the car’s heating system isn’t caused by its heater, but rather by the thermostat or the cooling system, it’s possible that the heater may itself be broken or clogged.