Here Are Some of the More Common Causes of a Broken Car Heater

By Product Expert | Posted in Service, Tips and Tricks on Wednesday, January 27th, 2016 at 7:08 pm
Reasons Why Your Car Heater Won't Work

Your car’s heating system is a collection of different components, sometimes making it difficult to diagnose a problem.

Reasons Why Your Car Heater Won’t Work

During the colder months of the year, nobody wants their car’s heat to stop working. Unfortunately, it does happen. There may be many reasons why your car heater won’t work, and that is why we generally recommend you schedule an appointment with a qualified service technician. If you’d like to look into the problem yourself, however, we can help.

Your vehicle’s heating system works by blowing air through the heater core and then out into the cabin of the vehicle, warming it up for passengers. The heater core is able to warm up this air through hot coolant from the engine. That’s the simple explanation, but as you’ll see, the heating system can be more complex.

In case your heater breaks, be sure to carry these items for a cold weather car emergency kit

Causes of a Broken Car Heater

mechanic fixing a car heaterSo why might your heater become broken or stop working? Here are some of the more common causes.

  1. Low coolant: This is a big one that is seen often. A low coolant level means the heater core isn’t getting the coolant it needs. Note: Wait for everything under the hood to cool down before checking the coolant level. Learn how coolant keeps your engine from overheating.
  2. Leak in the coolant system: This could be caused from anything from a leaky radiator cap to a loose hose clamp. Topping off your coolant could help for a while, but it’s a problem you will want to have investigated quickly.
  3. Thermostat problem: Problems with the thermostat could keep the coolant from warming up.
  4. Plugged heater core: Debris can build up in the heater core, blocking coolant flow. It may be possible to flush this out or it may require a replacement heater core.
  5. Faulty fan: Without a properly working fan, you won’t get the air you need. It could be busted or not blowing with enough force.

[Read more: Find out why your car rattles when coming to a stop]

As you can probably tell by now, attempting to find the reasons why your car’s heater won’t work can be a challenge. Since the vehicle’s heating system is made up of so many separate parts, it could take some time to diagnose the issue. Hopefully, your specific problem can be found within the above list of common causes, but if not, we recommend scheduling an appointment with a qualified automotive technician.

10 Responses to “Here Are Some of the More Common Causes of a Broken Car Heater”

  1. During the cold weather your car heater starts blowing and suddenly stop working in the middle of the winter. And your car heater is not working due to many reason. Car heater stop working if sufficient coolant is not there in the engine. If there is the problem occur in the heater core then also car heater stop working. If the coolant levels are good and there is no problem seem in the heater core then it is better that replace some of the control buttons of your heater control valve. Common problem, that the car heater is not working if there is a water leak.

  2. Eric layman says:

    It is really nice to know about different factors which could affects the performance of the car heater. Car heater plays very important role by keeping us away from the extreme temperature of the winter season. And, it’s condition should be evaluated at a regular interval and if damaged, then it should be repaired in time. Coolant level should be evaluated at a regular interval and if necessary should be replaced with appropriate alternative for efficient performance.

  3. Benny Rose says:

    A heater can stop working for a number of reasons like- A low antifreeze/water level in the radiator due to a leak in the cooling system, A blower fan that is not properly working, a bad thermostat that is not allow the engine to properly warm up. Relying upon different type of problem different types of repaired also necessary . For any of the above following reason if your car heater will not work then you can visit

  4. san juanita ramirez says:

    my heater in my vehicle is not working the button is popping back when i turn it toward cooling part of the a/c turning it to the heater part turns all the way

  5. Martylopez says:

    My heater was working but it stopped now it’s blowing cold air

  6. Olen Bush says:

    The role of car heater is to keep you warm, especially when the temperature of the outside is cold. The cooling system of the speed machine is directly linked to its heating system. Heater core, blower motor, HVAC panel, heater control valve- are the basis components present in the vehicle’s heating system. The cooling system must be kept in a good condition in order to keep heater running properly. And to keep the vehicle’s cooling system in a pristine order, you need to service it at the recommended interval by fixing an appointment with a certified car-geek- .

  7. Shanika Rathnayake says:

    A car heater helps to warm all it’s passengers. But sometimes the car heater doesn’t work due to some reasons. Low level of coolant in the engine means a heater core is not getting the coolant it needs. Therefore it doesn’t work. Sometimes due to a leak in the cooling system there is a low coolant level or antifreeze level in the radiator. That causes a heater to fail to do it’s work properly. Whatever may be the reason for failure of the car heater, we must diagnose and fix the problem with the help of a certified technician.

  8. Troya Marler says:

    Have you figured out why your heater is blowing cold. I am having the same issues we have flushed the coolant and have changed the thermostat, not sure what to do next

  9. george largan says:

    I have a 2012 Mazda with no heat at all , it has coolant , heater cor not clogged , heater motor works , good thermostat new . I just recently installed a new radiator. could there be air in the system and if so , how do you remove the air ? Help Mr. Chilie

  10. D. Heath says:

    2016 Mazda 6 heater has always been very slow to produce and heat. My thought was that the thermostat was either not working at all (stuck open) or that the temperature rating is not nearly high enough. Mazda service tells me it’s just a low temp thermostat and nothing can be done to replace it with a nice hot one….its just the way that car is. .??

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