Our 2001 4 cylinder Accord isblowing heat only part-time. Let me explain.

At low fan speeds, it blows some heat, although it never gets hot enough in the car that you can turn the rotary dial off of full hot. It takes 45 minutes of driving to get a comfortably warm interior. When you crank the blower fan, the warmth just dies off and the car blows only cool-lukewarm air.

So far, I have swapped the thermostat, checked the hot water valve on the firewall (working) and had the heater core reverse flushed with no noticeable improvement. What next? Could the heater controls in the dash be shot? Needless to say, this is getting kind of frustrating.

 

what happens when you idle the car? go you get heat?

 

Lately it's been about -15C at night. Starting the car to warm the interior, it takes 20 minutes or more to even get noticeable warmth. Yesterday we drove into Toronto from Waterloo, and I was rarely took the heat selector dial off full hot. It seems like for extended highway drives it can blow warm air or at low blower fan speeds in city driving it can blow warm air.

 

OK do this

Start car and drive it about 5 miles. come back home and park your car and let it idle. does the temp rise as the car idles? (if it does then you got a defective tstat) even when it is -15 outside car will still reach operating temp when it idles.

let us know the result of this test

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by YeuEmMaiMai &raquo;</TD></TR><TR><TD CLASS="quote">OK do this

Start car and drive it about 5 miles. come back home and park your car and let it idle. does the temp rise as the car idles? (if it does then you got a defective tstat) even when it is -15 outside car will still reach operating temp when it idles.

let us know the result of this test
</TD></TR></TABLE>

Mine takes forever to warm up, and once I idle it cools down fast..
never does it retain an "average" temp...
Soo does that sound Like i have a defective tstat?
If so, how easy is it to replace?
Will I have to bleed the radiator?

 

turn off your defroster next time you try this test and see if that helps.

A/C automatically turns on both fans so they can cool the car when it is at idle

yes Tstat is easy to replace as long as you drain system eough to lower the coolant below the tstat level

you will have to bleed the system when done but that is easy as there is a bleed screw on top of the tstat housing.

 

I dont ahve my ac on....



and it still happens

Also my defroster is off...

 

follow your fan's power wire and see where it goes. it should go to a relay. same for the second fan. You need to correct the cooling issues.

IF your fans are straight to 12V then you gotta fix it........

 

I've been having the same go-round with my 02 accord. Already changed TStat and flushed everything. Basically, its cold outside Seriously, it seems like these cars just run cooler, and when its super cold outside it makes it even harder for the engine to build up enough heat to warm the coils. If I spend more than 20 minutes or so in the car its fine, but until then it really takes forever to get heat....

 

Not sure what you mean by does the temp rise as the car idles?

Top rad hose is very hot, so the car must be at operating temperature if the tstat is cycling.

 

Most issues like that are due to a bad thermostat. The combination of your car taking forever to heat up, and no heat for a long time almost always is your thermostat. Also, there could be something wrong with your heatercore. If your coolant system isn't bled properly, it will take long for your heatercore to heat up. It's similar to a radiator in a house, but with a fan.
Also if you have a functional thermostat, once your car is fully heated up, turning on the heat full blast shouldnt change where the temp. needle is. If you turn on the heat on full blast once it warms up, and the temp needle drops over a few mins, it's another clue that the problem is the thermostat.

When the car idles he means Drive it around, then let it sit running in nuetral for a bit.

 

Until you get the radiator and the heating system back into top shape, try placing a <U>piece of cardboard </U>in front of your radiator -- as long as the weather is beastly cold. That's what we used to do in North Dakota on balmy 20 below zero days.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by gulfview &raquo;</TD></TR><TR><TD CLASS="quote">Until you get the radiator and the heating system back into top shape, try placing a <U>piece of cardboard </U>in front of your radiator -- as long as the weather is beastly cold. That's what we used to do in North Dakota on balmy 20 below zero days. </TD></TR></TABLE>

true, alot of people do that on older cars. think of it this way. its realllllly cold out, and yeah your engine is combusting which makes heat, but it may just be like say 200 degrees which makes the t-stat open and move new coolant in the block. now your heater core it flushed and has colder coolant in which means colder heat. if you block up the rad. then you're coolant isn't going to be able to cool down as much. just make sure you don't over heat. and yes its possible, i overheated at -11 with windchill on the highway.

 

Sorry about misunderstanding what you wanted me to test... had a little braincramp going on.

After driving, parking and idling, the temp gauge stays put and does not rise as the car idles. What should I check next?

 

do you start getting heat? if not then the problem may lie in the control unit not opening the panel or valve to let the coolant in

 

We get heat... very slowly. So I could have a problem with:

a) the actual control unit in the dash? Could I verify/test by swapping it out for
another?
or
b) the control valve on the firewall.

 

There is nothing wrong. The exact same thing you're experiencing happens in my car, and several others who have the same gen accord. These cars just run cooler, and the severe cold just makes it worse. I removed my thermostat and tested it, and it works fine....I changed it anyway and still have the same result. Get on the highway for about 15 minutes and I bet your heat blows plenty hot.

 

I'll even take a picture of my temp guage and I'll bet it stops at the same spot as yours. I'll try to get it up here tonight.

 

Just to let ya know...
I went down the highway 60 miles and it never left the cold area... hahaaa
Also, when I got stuck in traffic it did rise to the norm operating temps...
I do get warm air from the temp control...thing

 

What do you define as the "cold area". My temp guage will get to about 1/3 of the guage and STOP, regardless of highway driving, sitting in traffic, etc. This engine displaces heat better than any I've ever seen.

 

The normal for all the 5th gen accords is about 1/3 up. It all depends on what the scale is, doesn't mean this car necessarily runs cooler. Notice there is no numbers tied to the meter.
Anyway no, your car should not take 15 mins to warm up. It's bad for your car and there is a fix, I dont care if something is notorious for not functioning, you should fix it. I get heat within a few mins and I have a 94 with 177k miles on it. It may not be scolding but its warm air. If your car warms up but isnt putting out heat, it's usually a different thing. Either something wrong with your switches/***** or your heater core/coolant system.
If it's both taking a long time to warm up, and a long time to put out hot air, its usually air in your coolant system from never bleeding it, or a bad thermostat.

 

ok so the 3 other Accords I know personally with this mysterious "heat problem", and the several other posts in this forum for the same thing, ALL have bad thermostats huh?

This is my temp reading at 70, or at 20.....NEVER goes a single notch higher in the colder weather....

 

yes and that is perfectly normal for the needle to be there. Thermostats go bad on a regular basis and you don't really notice it in the summer, unless it runs the car to hot. Since you don't notice them half the year, they accumulate and you get a crapload of complaints on car forums once it's really cold. I'm not saying all of you have that problem, but it's a common occurance when you have heating issues.
Most of the time when a thermostat is stuck open, a car will eventually heat up to where it should be, but it will take forever, and in that time, the heat won't be efficient. A thermostat is a very primitive device compared to many components, relying on such things as wax, which can deteriorate. Sorry but I have a car that's much older than yours and I don't have a problem with my heat.

Do a search on coolant issues and see if you can find anything better. There has to be a cause... cars don't just "run cold". Also if you have your fair share of complains about a cold running car, get a thermostat that opens up at a higher temp. Also try feeling the line that's going to the heater core and see if it's hot...


Modified by Homesickelian at 10:26 PM 2/14/2007

 

having owned a 5th gen and a 6th gen accord, I can tell you that dispite what some people in here say, you get MASSIVE HEAT from these cars when they are at proper operating temp. living here in MN with temps in the -17 range for a few days my cars never had problem making heat my CL will start throwing heat within 3 miles of running from a cold start and my 94 and 98 V6 did as well...

If your temp guage does not rise or goes down when the car is moving forward, it is most likely (99.999999999999% of the time) your thermostat.

If your car reaches proper operating temp (this is east to tell if you have an auto since your TORQUE CONVERTER DOES NOT ENGAGE UNTIL THE CAR REACHES OPERATING TEMP and your rpms will be about 500 or so higher than normal.

If your car engine and trans are operating at the right rpm for the speed you are going then your problem lies else where

put your hands on the water hoses (98+ accords) going to the firewall and feel if they are hot, if they are. then the problem lies with the control head or door that blends heat with cold.

on 97 and earlier cars if the hose is not hot between the water valve and the firewall, your valve is busted internally or the control unit is not working.

 

update on my situation::

The temp is at the blue part ALL the time in cold weather....
Only warms up when I idle...
Sounds like a bad tstat?