Car Heater Blowing Cold Air
Posted in Internal Engine Parts | Asked on Feb 13, 2012
I have a Honda Civic 2003. It was overheating this summer and I had to take it to couple different shops to finally fix the overheating problem. (It has been been a 3 months battle). It finally stopped overheating after the last shop I took it in. However, every now and than the heater will start blowing cold air. I just recently had a coolant flush and replaced my thermostat. It takes the car almost 10 mintues to heat up and the heater will work fine, but than after a few minutes it would start blowing cold air. It doesn’t happen all the time, but it’s happened more than once. The other weird thing is – once it starts blowing cold air, i turn it to cold air for a few seconds and turn it back to heater and than it starts blowing warm air again.
There are 6 Answers for "Car Heater Blowing Cold Air"
The only thing i can think of its your heating coil if not try adding water/coolant or antifreeze to your radiator
Although I don’t have direct experience with your model of car, this problem is common with cars that use vacuum-assisted HVAC (heater/ventilation/aircondition) controls. You may find that there is a vacuum leak either under the dash or around the engine. If you hear a hissing sound under your vehicle’s dashboard, this is the likely problem.
That is def. a coolant problem. You need to go back to the shop that did your coolant flush and have them make sure there is no air in your system causing you to loose heat temp.. Having this problem can cause to another overheating issue and im sure you don’t want that again.. you can do the burp to your coolant system yourself..
Cartman is right. Low coolant. It blows cold air because there isn’t enough coolant to get into the heating element in the cabin. No hot coolant reaching the heating element = no heat.
The cooling system may not direct coolant to the radiator dependant on the coolant temperature (using the thermostat), but coolant will always flow to the cabin heater even if the thermostat is closed.
Sounds as though you have air trapped in the cooling system. With the engine cool, take off the radiator cap. Top off the radiator with a 50/50 mix of antifreeze and water. Start the car and let the engine warm up to normal operating temp. Top off the radiator again while squeezing the upper radiator hose to make sure all the air gets out of the system, then carefully replace the radiator cap.
If you got any water inside your car on the floor board passengers side, your heater core is leaking.