On cold mornings, I start my car 20 minutes before I have to leave for work. I turn the defroster all the way up.
When I get in the car 20 minutes later, the engine temp is up to normal, but the interior is freezing, and the windows are still frosted up like I never started the car. After about 3 miles down the highway, the heater starts blowing warm air. And now today, when I got to work (26 miles), the heat was blowing cool air. The blower motor is fine, just not hot air.
It Sounds Like It’s Low On Coolant Or Has Air Trapped In The Cooling System.
Don’t delay in getting it checked. This could lead to bigger problems than no heat.
You’re wasting a lot of gas for nothing. The engine should start to warm up in just a minute or two, and you should have at least some warm air as soon as the temp gauge starts moving.
There are several possible problems, and without knowing what you drive it’s hard to say which is applicable.
First, check the level of the coolant in the radiator. Do this when then engine is COLD. You have to remove the radiator cap and look inside. Looking at the overflow bottle is not good enough. There should be coolant right up to the bottom of the radiator cap.
If your car has a control valve to allow coolant to flow through the heater core you will have to check to see if it’s working. If there is no valve the core should be hot whenever the engine is warm, but feel the hoses going to and from the core as a check. When the engine is at normal operating temperature both hoses should be hot.
If the heater core is hot the problem is in the ventilation system under the dashboard. Airflow is controlled by movable doors, or flaps, and if they are not moving into the correct position the air won’t flow through the heater core, and will not be warmed.
Some systems use vacuum to move the doors and some use electric motors. A vacuum leak, a failed motor, or a physical obstruction, can prevent proper operation of the air control flaps.
Thanks, sure enough I just checked my coolant and I’m really low.
Thanks again.
Now you have to figure out where the coolant went.