Posted on 9/26/2025
A freezing car cabin in the middle of a Canadian winter makes driving uncomfortable, more difficult, and unsafe. If your car’s heater suddenly stops working or only blows cold air, it’s a sign that something in the system isn’t functioning correctly. The heater relies on several components working together to warm the air and direct it into your vehicle. When one of those parts fails, you feel it immediately. These are the five most common reasons your heater is not doing its job when you need it most. 1. Low or Leaking Coolant Your car’s heating system uses engine coolant to create warm air. The hot coolant flows through the heater core, which acts like a mini radiator inside your dashboard. When the blower fan passes air over it, that warm air gets pushed into the cabin. If your coolant level is too low, there won’t be enough hot fluid circulating to warm up the heater core. Leaks in hoses, the radiator, or the water pump can cause t ... read more