Low Level of CoolantYour engine’s coolant (typically a water-and-antifreeze mixture) serves as both a heat sink and a heat source for the heating system. To compensate for the lack of coolant, the heater core will force cold air into your vehicle.
Why is my car heater not blowing hot air?
Engine overheating and a lack of hot air can both be caused by faulty heater cores and low or contaminated coolant levels.
Why is my heater blowing cold air instead of hot?
When your furnace is blowing cold air into your house, it could be a sign that something is wrong with the flame detector, gas supply, air filter, pilot light, or condensate lines. Many of these problems can be easily resolved by sanitizing or replacing gas furnace components.
Can low coolant cause no heat?
You won’t have any heat if your radiator is severely depleted of coolant. If the levels are correct, the problem is most likely with the water pump or the thermostat.