The heater switching system might be faulty. The cabin air filter might be choked, restricting the airflow through the heater core. The thermostat valve might not be working right. The heater core might be clogged.
Why is my car blowing cold air when the heater is on?
Low Coolant Level
The coolant (usually a mixture of water and antifreeze) in your engine doesn’t just work to keep the engine from overheating: It’s also the source of heat supporting the heating system. If there isn’t enough coolant in your system, the heater core will blow cold air into your car.
How can I make my car heater warmer?
Many people think so, but the car interior will heat up no faster than the engine coolant heats up. Block the radiator with a piece of cardboard is the cheap solution. Use a block heater for the engine and it will be warm when you get in it.
Why is cold air coming out of my vents when the heat is on?
Your Air Filter Is Dirty
Clogged air filters could be causing cold air to blow out of your vents. A dirty air filter can block airflow over your furnace’s heat exchanger, which can cause it to overheat.
How do I know if my heater core is clogged?
Heater core failure symptoms
- Weak or no airflow.
- Cold air (not warm) coming through the vents when the heater is on.
- Coolant leakage visible inside the cabin or a damp smell.
What to check if heat is not working?
What to Check First If Your Heater Isn’t Working
- Check the Furnace Power Switch. Some furnaces have an on/off switch that is frustratingly easy to switch off by mistake. …
- Look at Your Fuse Box That Powers Your Heater. …
- Check the Batteries in Your Thermostat. …
- Replace the Air Filters. …
- Notice Any Odors. …
- Heater Isn’t Working?
What are the symptoms of a bad thermostat?
Bad Thermostat Symptoms
- Overheating Engine. If the thermostat stays closed, the engine’s coolant cannot reach the radiator and, therefore, cannot cool down. …
- Temperature Fluctuations. …
- Heater fluctations. …
- Possible Leakages & Steam from engine. …
- Rising Temperature and Full Expansion Tank.
Why is my heat and air not working in my car?
A faulty or broken thermostat is the most common cause of your car’s failing heat. Stuck open or stuck closed, the part can not only cause issues with your heat but also your engine’s cooling system. One becomes an issue of comfort, the other becomes an issue of “Oh no, I’ve borked my engine.”
Why are some vents blowing cold air in car?
This situation can be caused by a bad blend door (also called air mix) actuator, a broken or binding blend/air mix door, broken linkage to the blend/air mix door, or a faulty HVAC control head or wiring harness.
How do I fix cold air coming out of my vents?
How to Keep Cold Air Out of Your Vents
- Install insulation. Poor insulation causes rapid cooling of the air as it moves through your home. …
- Check connections. Over time, the connections in your ductwork can come loose. …
- Update your HVAC. Older HVAC systems are less efficient and require more upkeep than modern models.