Car Heater Blowing Cold Air? Here Are 7 Possible Reasons

car heater blowing cold air

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You step into your cold car on a cold morning and turn the key, only to hear the hum of an engine without any heat blowing through your vents. 

So you turn up the dial thinking it will finally give you some heat but still – nothing. 

You check all the hoses looking for cool spots or leaks, but find nothing wrong so you let it run for a bit not knowing what else to do. 

You turn the dial all the way up and still nothing. All you get is cold air blowing through your vents so you jump out of your car to get warm somewhere else, leaving it running. 

Or you can grab your portable heater if you get desperate.

You may wonder why the car heater is not working – here are 7 possible explanations:

7 Reasons why the heater is blowing cold air in the car

1. Your car is more than likely low on coolant

This is the most common reason why the engine runs without heat blowing through your vents, especially during colder months. 

The solution would be to add some more coolant into your car’s radiator system. 

Driving with a low coolant level can cause overheating, which is bad for your car’s engine. 

It can also help to have your radiator checked as it may be clogged or dirty due to age and use.

2. Your air intake hose is loose or disconnected

The next thing you should check is the condition of your air intake hose where it connects under your car’s hood. 

This rubber hose supplies the engine with fresh air from outside so that it can breathe properly and run correctly. 

The engine needs this in order to generate heat by burning fuel inside the cylinders. 

Driving around without this hose connected will cause the car to overheat and not perform at all like it should. 

You don’t want this to happen do you? Tighten up anything that seems loose or connected to see if that helps the situation.

3. Your heater core is clogged or leaking

The heater core is a small radiator inside your car underneath the dashboard, usually where the glove compartment and ashtray are. 

Warm air from around your feet is sent through this radiator so heat can be produced inside of it and blown through the vents in your car’s interior. 

The reason why you have no heat in the car might be because there is a blockage somewhere in the system preventing any heat from getting into your vents. 

If you blow some compressed air through it while turning it on, this should help get rid of anything that may be restricting it from working properly again. 

Check for leaks by putting water into a cup and pouring it on all of the tubes and connections under your dashboard. If you notice water dripping from one spot you might have a leak so fix it as quickly as possible.

car heater blowing cold air

4. Your heater control valve may be stuck

The heater control valve is a shut-off that switches the system from blowing hot air to cold depending on how it’s set. 

This may become stuck when closed, causing your car to blow cool air instead of warm. 

If you have no experience working with the inner workings of a car I would not suggest opening this up because you could do damage or hurt yourself by getting burned by hot steam or escaping gasses. 

Your best bet would be to take it in for a professional inspection and cleaning if needed so they can fix it properly and give your engine heat once more.

5. There’s an issue with the thermostat

If there are no leaks, blockages or loose hoses your problem could be your thermostat

A badly installed thermostat will cause the engine to not produce any heat at all. This is because it regulates how much coolant goes into the radiator depending on temperature levels outside and inside of the car. 

Your air conditioner system also requires a properly working thermostat in order to work correctly. 

Replacing this part can be tricky but you need to know if this is what’s causing your car heater to blow cold air before you go spend money on new parts for something that may just be a small switch made of plastic.

6. The outside temperature is too low

You should check the actual outside temperature to see what it’s like. This can explain why the car is running for a while with no heat being produced, so keep this in mind.

On very cold days you need to let your car run for at least 10 minutes before using the heater just so that everything can get warmed up enough to start producing heat inside of it. 

If not, then all you are doing by turning on your heater is draining your battery which doesn’t help anyone! 

On colder mornings there may be less heat produced because extreme cold outside makes it hard for your car’s engine to generate any warmth while running during these conditions.

7. Car heater is broken

If you have gone through these steps and still don’t see any heat blowing into the vents in your car, then this may be a sign that something is wrong with the actual heating system. 

If you have recently gotten your car worked on by mechanics, they could’ve messed something up when taking care of another problem. Or maybe there was a fire in your car? 

This definitely would cause permanent damage to the heater core or some other part of the system, but talk to a mechanic if this has happened because the safety of you and others should always come first. In some cases you may need a whole new heating system installed in your car if something has been fully destroyed by an accident. 

It’s best to have everything looked at by a mechanic because they know exactly what to look for and replace if needed.

In Conclusion

So, the answer to the question: “Why is my car heater blowing cold air”?

Car heater problems can be a real inconvenience, especially if you have already made plans to go somewhere and assumed your car would be warm enough. 

Hopefully these steps have helped you figure out what the cause of your chilly interior is, so that way you know where to start when fixing it. 

Don’t forget about the outside temperature, though, because this does affect how well your heater works.

Have a good day everyone!

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