Here’s how your car heater is supposed to work:
- Get into car, turn on ignition, adjust heating controls.
- Shiver patiently as cold air blows into your cabin, confident that warm air is coming soon.
- Reach your destination in comfort.
But sometimes your heater stops on Step 2. Something breaks in your vehicle’s HVAC system or disrupts coolant flow from your engine radiator. Bundle up and head to Midas.
Our Midas Auto Service Experts® take the time to thoroughly explain why your heater just won’t heat, and discuss the best options for your budget. We’ll provide a written estimate before making any repairs. Request an appointment today.
Why is my car blowing cold air when the heat is on?
Cold air from your heater is normal for the first few minutes of operation. If the air from your vents doesn’t heat up shortly, you’ve got a problem with your heater or your coolant. Your heating system borrows coolant (water + antifreeze) from the engine radiator, so if there isn’t enough coolant for both systems, the engine gets the available coolant. Another possible culprit: your engine’s water pump is failing to recirculate coolant back to the radiator – again leading to a coolant shortage for the heater.
What would cause the heater to stop working in a car?
- Low coolant: Your heater shares a coolant supply with the engine radiator. A radiator leak or bad water pump can leave the heater core without coolant.
- Bad heater core: In addition to leaks, your heater core can fall victim to holes and blocked coolant hoses.
- Bad blower motor: This could prevent heated air from reaching your cabin.
- Bad HVAC controls and valves: Over time, these small parts can break or get stuck.
- Broken or stuck thermostat: Even a mint-condition heater with plenty of coolant needs a thermostat to tell it to kick in.
What are the signs of a bad heater core?
The heater core is a small, radiator-like device that usually sits behind your dashboard vents. Coolant enters the core, takes in heat, and then exits to warm up the air being blown into your cabin. Here are some common signs that your vehicle’s heater core needs service:
- Your heater blows cold air: A punctured or otherwise damaged heater core can prevent heat transfer.
- Your cabin fogs up, after warming up: Coolant running through a bad heater core stays cold. The air blowing into your cabin cools down. If your cabin is already warm, condensation accumulates on all your windows.
- Your car smells sweet or bitter: If your heater core leaks, you may notice the fruity or bitter odor of coolant in your cabin or outside the vehicle. You may also have a radiator leak.
- Your coolant level drops: Another sign of a coolant leak in your heater core or radiator. Be alert to the risk of overheating.
- Your vehicle overheats: A blocked heater core can overheat your engine and strand you on the road.
What to do if your car overheats Request Appointment