Heater blows cold air at idle but works great above 25 MPH

originally posted by: seattlerat
Thanks to all of you for the replies so far- I have some things to try and will get back with what (hopefully) worked!

To answer some of the questions:

* No water on the floor near heater core location
* Thermostat was NOT replaced and engine temperature is normal (gauge shows exactly the same as it always has just below halfway)
* I did try to bring rpm up while in park and it didn't seem to make a difference, I'll try this again today

I hope it doesn't have anything to do with water-pump. I've changed a thermostat before so I could try that if adding coolant and parking on hill technique doesn't solve the problem.

You guys are great!

Thermostat stuck in the open position

when my cars always did that most of the time i was low on antifreeze might just be that simple

Thanks again for all of the suggestions!

I did everything I could to resolve this issue but I was unable to solve it and just lived with no heat at idle.

Then, about 10 days ago, after sitting at idle for 40 minutes talking on the damn phone, I looked up and noticed that the temperature gauge was beyond pegged! ARGH!!!!

So, I let it cool off, checked fluids (they were OK), and drove it about a mile to a local repair shop.

I received a call a short while later, "We have news, but you're not gonna like it- you have a blown head-gasket and for the low-low price of $2500 you can have heat again."

I'm not made of money, actually, I'm mostly water, but the car is in otherwise near perfect condition and I couldn't find anything better to replace it for $2500. So, I opted for surgery. The mechanic informed me that I could save some money by not replacing timing-belt, but I opted for the full menu.

Head gasket, timing belt, thermostat, spark-plugs, water pump, oil/filter, head re-surfacing, valve height adjustment, coolant, misc. shop supplies: $2304.

The car runs great, and now I have heat at idle!!! Unfortunately, I'm pretty much broke, so time for me to stop being lazy and earn some cheese.

ETA: I considered doing the work myself, however, even if I had my own garage and all of the required tools/equipment, I probably would not have tackled an automotive repair as extensive as this. I looked online at some DIY head-gasket replacements for 2005 Honda Civics, and it did not look like it would be much fun. I value the skin on my knuckles!