2005 Honda Civic Q&A
2005 Honda Civic Question: Car not blowing hot air when low rpms or at idle
check the coolant level first. if it is low, you need to find the leak and repair it. if it is ok, check the thermostat for operation. make sure your cap is working correctly. lastly, could be a restricted heater core. Roy - mastertech6371
You might have a bad head gasket. I had a similar problem and changed the thermostat. Coolant is leaking and seaping through the bad head gasket. You will need to replace the head gasket for sure. - Visitor
A few days ago, I noticed (the last time I had my car's oil changed (about a month ago))someone there overfilled the coolant! Then, today when driving it, all of a sudden it no longer blew hot air!...