Heater - Blowing cold air - HondaCivicForum.com

Thread Tools Search this Thread
Old 12-21-2010, 05:51 PM
HCF Member
Thread Starter
Join Date: Sep 2007
Posts: 50
Default Heater - Blowing cold air

Hi everyone. I think this is the correct section for this. If not, please move it accordingly.

A couple weeks ago my heater started acting up. It wouldn't blow hot air unless I was at a minimum of 2k RPMs. If I was at an idle it would still blow, but it would be cold. Now, it won't blow hot air at all. The coolant reservoir was empty, so I filled it up to under the max line. Turned the car on and let it sit awhile while running and still no heat. With the engine running I looked at the reservoir and saw no fluid moving. With the engine only running about 10 minutes, I popped the cap off the radiator and saw no fluid inside. I saw no circulation of anything.

What could be causing this issue?

'98 Civic EX. D16Y8 engine (I believe). Here is an old thread of the engine if you need to see. https://www.hondacivicforum.com/foru...ad.php?t=51857
Reply With Quote
Old 12-30-2010, 12:24 PM
HCF Member
Join Date: Jan 2009
Location: AZ
Posts: 226

There are a few things that can cause this. Check the blend door under the glove box, to see if the cable from the hot/cold control is working. Is the car warming up all the way? if not then you may need a thermostat. Is the control valve leading to the heater core working? It is in the engine bay by the fire wall on the trans side. There is a cable going to it that opens the coolant flow to the heater core. Make sure the cable is working and not broken. The heater core could be plugged up. Do you do regular service to your car ie cooling system flushes? Oh and make sure the radiator is full of coolant also. Hope some of this helps.
Reply With Quote
Old 02-16-2011, 10:21 AM
HCF Member
Thread Starter
Join Date: Sep 2007
Posts: 50

What was confusing me was that the radiator was leaking. I only noticed it after all the leaves were cleared from the street and there was a huge puddle under the car. Replaced the radiator and now the heater works fine.
Reply With Quote
Old 02-16-2011, 10:37 AM
WellFedHobo's Avatar
Join Date: Jul 2007
Location: Arkansucks
Posts: 4,945

moved to tech section.

That makes sense, actually. Low coolant from radiator leak = air in the system. Air = no hot engine coolant getting to the heater core. When you were at higher rpms, the pressure was forcing the air to circulate with the coolant, so some of the hot coolant was getting to the heater core.
Reply With Quote

Related Topics
Thread Thread Starter Forum Replies Last Post
Overheating/heater blowing cold air Kadels2 Mechanical Problems & Technical Chat 5 03-04-2016 10:07 AM
2004 Honda Civic - Over Heating/heater blowing cold redlillian Mechanical Problems & Technical Chat 8 01-19-2012 03:30 PM
Car heater blowing cold air sometimes rohan076 Mechanical Problems & Technical Chat 4 05-17-2011 08:24 AM
Heater blowing cold air after removing and replacing heater control panel tgs Mechanical Problems & Technical Chat 10 03-28-2010 07:12 PM
Heater not blowing alot of air!! sketchen Mechanical Problems & Technical Chat 1 12-26-2009 02:00 PM

01, 1998, 2000, 98, air, blow, blowing, blows, civic, cold, heater, honda, hot, moving, wont

Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off

Featured Sponsors

All times are GMT -8. The time now is 09:18 PM.