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Why is my crosstrek not blowing hot air?

If your Subaru Crosstrek is not blowing hot air, it could be due to a few common issues. The most likely causes are a problem with the heater core, a faulty thermostat, or low coolant levels. Let's dive into the details to help you diagnose and fix the issue.

Potential Causes for No Hot Air in Your Crosstrek

There are a few key reasons why your Crosstrek may not be blowing hot air from the vents:

Heater Core Issue: The heater core is responsible for heating the air that blows into the cabin. If the heater core is clogged or damaged, it won't be able to effectively heat the air.

Thermostat Malfunction: The thermostat regulates the flow of coolant through the engine and heater core. If the thermostat is stuck closed, it won't allow enough hot coolant to circulate, resulting in no hot air.li>
Low Coolant Levels: If your Crosstrek is low on coolant, there won't be enough hot liquid circulating through the heater core to warm the air. This can be caused by a leak in the cooling system.

Other less common issues could include a problem with the blower motor or a blockage in the air ducts. But the three main culprits are usually the heater core, thermostat, or low coolant levels.

Diagnosing the Problem

To figure out the root cause, you'll want to do some basic troubleshooting:

Check the coolant level and top it up if needed.

Feel the heater hoses - they should be hot when the engine is warmed up. If they are cold, the thermostat may be stuck closed.

Inspect the heater core for any signs of leaks or blockages.

Use an infrared thermometer to check the temperature of the air coming from the vents. If it's not getting hot, the issue is likely with the heater core or thermostat.

Once you've identified the problem area, you can take the appropriate steps to repair or replace the faulty component.

Fixing the Issue

If the problem is a bad heater core, you'll need to have it replaced by a mechanic. This is a more involved repair that requires draining the coolant system and removing the core.

For a stuck thermostat, you can try replacing it yourself. This is a relatively straightforward job that just requires draining some coolant and swapping out the old thermostat.

If the issue is low coolant levels due to a leak, you'll need to find and fix the leak before topping up the coolant. This could involve replacing hoses, the water pump, or other cooling system components.

No matter the root cause, addressing the problem promptly is important to prevent further damage to your Crosstrek's engine and cooling system. With the right diagnosis and repair, you'll have that warm air blowing in no time.

Why is my Subaru blowing cold air when the heat is on?

Your Subaru is likely blowing cold air because of a coolant system issue, such as low coolant, air pockets, or a faulty thermostat, which prevents heat from reaching the heater core. Other causes can include a clogged heater core, a problem with the heater control blend door, or issues with the heating controls.
Possible causes

Low coolant level: The engine's coolant transfers heat to the heater core. If the level is low, there isn't enough coolant to circulate, and the cabin will get cold. This is often due to a leak in the radiator, hoses, or water pump.
Air in the cooling system: After coolant is refilled, air can get trapped in the system. Air pockets can block the flow of coolant to the heater core, which is often the highest point in the system.
Faulty thermostat: A thermostat that is stuck open or not working properly will prevent the engine from reaching its optimal operating temperature, meaning the coolant won't get hot enough to heat the cabin.
Clogged heater core: The heater core can become clogged with debris, preventing warm coolant from flowing through it. This can cause a sweet smell or foggy windows inside the car.
Faulty blend door actuator: The blend door inside your dashboard mixes hot and cold air. If the actuator for this door is broken or malfunctioning, it may not be directing air over the heater core, even if the heater is on.
Heating control issues: The problem could be with the cables or electrical components that control the heating system, which may prevent them from correctly signaling the system to provide heat.

This video explains the potential causes of your car's heater blowing cold air: 57s1A Auto: Repair Tips & Secrets Only Mechanics KnowYouTube · Oct 19, 2022
What you can do

Check coolant level: When the engine is completely cool, check the coolant level in the overflow reservoir and add coolant if needed. If the level is consistently low, it indicates a leak that needs to be found and fixed.
"Burp" the system: You can try to remove air from the cooling system by parking your car on an incline with the front higher than the back, and then carefully bleeding the air from the system.
Professional diagnosis: If simple checks don't resolve the issue, it's best to have a mechanic perform a professional diagnosis. They can accurately identify and fix problems like a clogged heater core, a bad thermostat, or a faulty blend door actuator.

This video shows what a clogged or leaky heater core looks like: 49sTop 5 Auto RepairsYouTube · Sep 14, 2023

Why is my car suddenly not blowing hot air?

If you notice your car heat not blowing hot air, low coolant levels might be the culprit. If your coolant levels are low, there might not be enough to heat up and warm your car. This can happen due to leaks or evaporation over time.

What is the common problem of a Subaru Crosstrek?

Common Subaru Crosstrek problems include infotainment and electrical glitches (like screen freezes or connectivity issues), problems with the CVT (Continuously Variable Transmission) such as shuddering or delayed acceleration, and exterior issues like easily cracked windshields or fading paint. Some older models have specific issues, such as excessive oil consumption or engine problems.
This video discusses common problems with the Subaru Crosstrek, including issues with the transmission, engine, and electrical systems: 1mFuel ForceYouTube · May 5, 2025
Infotainment and electrical problems

Glitches: The infotainment screen can freeze, become unresponsive, or reboot unexpectedly.
Connectivity: Issues with Bluetooth connectivity and Apple CarPlay are frequently reported.
Other electronic issues: Malfunctions in driver-assist functions, the backup camera, and key fobs have been noted.
A/C system: Some owners report the A/C system intermittently failing to respond to settings.

Transmission and engine concerns

CVT issues: Many owners report shuddering, hesitation, or a droning noise from the CVT.
Engine noise: The engine can be loud during hard acceleration due to the CVT keeping RPMs high.
Oil consumption: Older models, particularly from 2012–2015, have reported excessive oil consumption.
Engine failure: Some older models experienced engine failure due to fractured valve springs, leading to recalls.

Exterior and interior issues

Windshield cracking: Some models are susceptible to windshields cracking easily under minor stress.
Paint and trim: Fading, peeling, or cracking paint and issues with exterior trim have been reported.
Rust: Some owners have reported issues with rust.
Interior rattles: Rattles from the A-pillars or behind the dashboard can occur.

Why is my heater blowing air but not hot?

If your heater is blowing air but no heat, it's likely due to a problem with the ignition system, thermostat, or airflow. You can start by checking simple issues like the thermostat settings and cleaning or replacing the air filter. If these don't work, a dirty flame sensor, pilot light, or a tripped high-limit switch could be the cause, and a professional should be consulted for more complex issues like a faulty gas valve, clogged burners, or a cracked heat exchanger.
Simple checks and fixes

Check thermostat settings: Make sure the thermostat is set to "heat" and the temperature is higher than the current room temperature. If it's a digital thermostat, check the batteries.
Check and replace the air filter: A clogged filter restricts airflow. Check it and replace it if it's dirty. A dirty filter can also trigger the high-limit switch, which shuts off the heat to prevent overheating.
Cycle the power: Turn the furnace off, wait a few minutes, and then turn it back on. This can sometimes reset a tripped safety switch.
Check the gas supply: If you have a gas furnace, ensure the gas valve is open. The handle should be parallel to the pipe for the "on" position.
Relight the pilot light: If your furnace has a pilot light, it may have gone out. Follow the manufacturer's instructions to relight it. If the pilot won't stay lit, it could indicate a problem with the thermocouple.

When to call a professional

Safety switches: If a simple reset or filter change doesn't work, the issue could be a safety switch like the high-limit switch or flame sensor.
Gas valve or burner issues: Problems with the gas valve or burner igniters require professional servicing. They can also be a fire or carbon monoxide hazard.
Cracked heat exchanger: A cracked heat exchanger is a dangerous issue that requires immediate professional attention and a complete system replacement.
Ductwork issues: If the air isn't circulating properly, there could be a blockage in the ductwork. A professional can inspect and repair the ducts.

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Kevin Bennett

Company Owner

Kevin Bennet is the founder and owner of Kevin's Autos, a leading automotive service provider in Australia. With a deep commitment to customer satisfaction and years of industry expertise, Kevin uses his blog to answer the most common questions posed by his customers. From maintenance tips to troubleshooting advice, Kevin's articles are designed to empower drivers with the knowledge they need to keep their vehicles running smoothly and safely.