When you turn on your car’s heater, it should start blowing warm air. If the engine is already at operating temperature, this should happen immediately. However, if your engine is cold, it will take longer and if the weather is cold, the process is even lengthier.
There’s no real answer to how long it should take a heater to warm up during cold weather. It really depends on several different factors. One of those is the type of vehicle you’re driving. Most older cars can require several minutes or so to come up to operating temperature and for the heater to start working. However, some newer cars require only a minute or two. Another factor is the temperature – if it’s very, very cold (think northern Minnesota in January), then it can take longer for even newer cars to build up enough heat to create warm air in the cabin. Other considerations include the following:
Thermostat Condition: The thermostat in your car restricts coolant flow depending on engine operating temperature. If it’s stuck open, your heater might never blow warm air because the engine’s operating temperature never reaches the right level.
Low Coolant: If your engine coolant level is low, your heater might blow mildly warm air, or it might blow only cool air. That’s because your car’s heater works on coolant – the coolant cycles through the engine, absorbs heat, and then transports that to the heater core in your dash, where it’s used to warm the air blown out of your vents.
If your heater takes a long time to warm up, or never warms up at all, it’s a sign that there’s something wrong, and you’ll need to your heater inspected and diagnosed by a professional mechanic.