During the cold weather, when I have turned on the heat, no warmth comes out only cool air even after engine is at normal operating temperature. I have about 52k miles on the car. Is it possible that I need a new thermostat or need to add more coolant? I read posts that say to use Honda Type II coolant, but that it shouldn't need to be replaced for at least 5 years. This is why I suspected that I may need to replace the thermostat. If it turns out the thermostat is fine, should I completely drain the coolant system before adding the new coolant? Any help getting the heat to work again in my car would be much appreciated. Where should I get thermostat (which one) and where should I get coolant from?

Thanks,

Matt

 

Generally thermostats fail closed and then your car would overheat and you would still have heat.

They can fail open though but then it would take a very long time for the car to warm up. Is it taking a long time for the car to warm?

Also with a warm weather car like ours there is a chance that the heat has never been turned on resulting in the heater core being plugged or the mixing valve being frozen. Did you buy it used or have you used the heat before?

And lastly if you think the coolant is low you should check it. Im sure the owners manual tells you how to check it.

 

You say that the engine reaches normal temperature - therefore the thermostat is okay.

The first thing to do when the heater blows cold is make sure the cooling system is full of coolant. Do it by the book to make sure there are no bubbles.

It is possible that the valve which is supposed to open and let coolant flow through the heater is not opening. It's near the battery, controlled by a cable.

 

things to check: at the firewall make shure heater hoses are warm/hot coming in and out , make shure cable is opening heater valve, have someone inside car changing knob back from cold to hot. If all that works check blend door under dash, if the blend door is not working(motor that operates door)you will not get any heat at vents. T-stat will not cause no heat coming out of vents, but improper mix or old coolant will.

 

Problem is in heater control/power ground:
Check fuse #54 (30A) located in the main under the hood fuse relay box
Check fuse #20 (7.5 A) located under the dash fuse relay box
Chck fuse #25 (7.5 A) located unde the dash fuse relay box

I'd start with the last two as your blowing cold air....good luck!

Utah

P.S. Problem is not related to thermostat or coolant level

 

It could also be some air trapped in the lines causing the fluid to not flow through the heater hoses correctly. I had this happen when I forgot to bleed it off after changing mine. In the Helms manual it shows exactly which ones to bleed and it worked.

 

[QUOTE=dhayner,Mar 5 2005, 02:44 PM]It is possible that the valve which is supposed to open and let coolant flow through the heater is not opening.