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-   -   Heater blowing warm (not hot) air (http://www.wranglerforum.com/f210/heater-blowing-warm-not-hot-air-197193.html)

humpaco 11-03-2012 08:41 AM

Heater blowing warm (not hot) air
 
Bought a 2002 TJ Wrangler over the summer and love it. Issue is that it is blowing warm (not hot) air from the heater. I read hundreds of posts on this and think I have done/checked everything. Coolant level is fine. Temperature is running at 210 degrees. Both hoses going into the firewall are very hot to the touch. I removed both hoses and flushed the heater core both ways. Does not seem to be any obstructions as water flows freely both ways. Blend door actuator motor is working properly. Removed the actuator motor and manually turned the blend door. I can hear hear it move in both directions so that seems fine as well. Air Cond works fine. Its getting cold here in NJ so trying to fix this issue asap. Any advice? This is driving me crazy. Thanks.

Phaeton 11-03-2012 09:11 AM

Seems like you covered everything. Mine does not blow so hot either. If you figure it out please let us know.

tallzdatank 11-03-2012 09:25 AM

leak in your ducting?

z21-i 11-03-2012 10:00 AM

I had this problem last winter. Previously I had put one of the Autozone thermostats into the Jeep that sticks open if it fails. Replaced it with a conventional one and my problem went away.

tangofox007 11-03-2012 11:15 AM

Quote:

Originally Posted by z21-i (Post 2956250)
I had this problem last winter. Previously I had put one of the Autozone thermostats into the Jeep that sticks open if it fails. Replaced it with a conventional one and my problem went away.

A temp of 210 contraindicates an open thermostat.

572 11-03-2012 11:28 AM

Have you tried CLR?

I flushed my heater core and some gunk came out, and the heater is warmer now, but it still doesn't get as hot as I'd like.

I've been thinking about putting a little CLR in the heater core for a while then flush it out real good and see if it helps. I've heard some folks have had good results doing this.

SurfKaster 11-03-2012 11:56 AM

PO might have removed the thermostat.

jeepsrgreat 11-03-2012 01:05 PM

Hope you can find the answer. I'm trying things too. Heater use to make my foot so hot, I couldn't have it on high. Now it's only warm.

s14sh3r 11-03-2012 01:09 PM

Mine's the same way. Runs at 210, flushed the heater core and it flows freely and no junk comes out. Used CLR. Cooling system is clean. Blend door is not stuck. It just doesn't put out much heat. I'm thinking I'll have to replace the core eventually. For some reason it's not transferring heat from the coolant.

Shelby427 11-03-2012 01:37 PM

Something I found on ours when I had to replace it, the bottom half of the core was all plugged up on the outside. Dirt/debris had built up, coming in through the fresh air intake. When it got wet it turned to more or less mud and the blower had pushed it into the core fins, blocking any airflow on the bottom half.

Might be worth a shot to pull your blower motor and taking a look inside the housing.

steve67 11-03-2012 04:21 PM

Quote:

Originally Posted by Shelby427 (Post 2956791)
Something I found on ours when I had to replace it, the bottom half of the core was all plugged up on the outside. Dirt/debris had built up, coming in through the fresh air intake. When it got wet it turned to more or less mud and the blower had pushed it into the core fins, blocking any airflow on the bottom half.

Might be worth a shot to pull your blower motor and taking a look inside the housing.


with all he has done , this sounds like it could be the problem.
i am saving this post.

tangofox007 11-03-2012 04:31 PM

Quote:

Originally Posted by Powder Monkey (Post 2956546)
PO might have removed the thermostat.

And the temp is at 210?

humpaco 11-03-2012 05:05 PM

Quote:

Originally Posted by Shelby427 (Post 2956791)
Something I found on ours when I had to replace it, the bottom half of the core was all plugged up on the outside. Dirt/debris had built up, coming in through the fresh air intake. When it got wet it turned to more or less mud and the blower had pushed it into the core fins, blocking any airflow on the bottom half.

Today I went in and stuck my finger up in the fresh air vent in the firewall that comes down from the hood. I got a bunch of dirt out. Do you think that is related to the lack of hot air? Is there a way to check for blockage without having to remove the core? Thanks for the information/advice.

s14sh3r 11-03-2012 05:20 PM

Quote:

Originally Posted by Shelby427 (Post 2956791)
Something I found on ours when I had to replace it, the bottom half of the core was all plugged up on the outside. Dirt/debris had built up, coming in through the fresh air intake. When it got wet it turned to more or less mud and the blower had pushed it into the core fins, blocking any airflow on the bottom half.

Might be worth a shot to pull your blower motor and taking a look inside the housing.

Quote:

Originally Posted by humpaco (Post 2957220)
Today I went in and stuck my finger up in the fresh air vent in the firewall that comes down from the hood. I got a bunch of dirt out. Do you think that is related to the lack of hot air? Is there a way to check for blockage without having to remove the core? Thanks for the information/advice.

You know, I wondered if corrosion inside the core was keeping the heat in, but I never thought about actual dirt inside. Hmmm... now I have something to check. Thanks! :thumb:

scott howard 11-03-2012 06:33 PM

A easy check to see if your heater core is stopped up with dirt on the outside and not letting the air flow thru it freely to transfer the heat to the ducts of the Jeep is to set it on defrost and temp on cold and feel how much air is flowing . Now switch it to Hot and see if it loses a lot of air flow( it will be a little less just because it has to blow thru the core but it should not be a lot less ) if so your core is clogged with dust and dirt and need cleaned .
The best way is to remove it but if you pull the blower motor and you have a air compressor and a nice long air gun you can sometimes blow it out.
Be careful and not bend the honeycomb closed.

s14sh3r 11-03-2012 06:53 PM

Quote:

Originally Posted by scott howard (Post 2957433)
A easy check to see if your heater core is stopped up with dirt on the outside and not letting the air flow thru it freely to transfer the heat to the ducts of the Jeep is to set it on defrost and temp on cold and feel how much air is flowing . Now switch it to Hot and see if it loses a lot of air flow( it will be a little less just because it has to blow thru the core but it should not be a lot less ) if so your core is clogged with dust and dirt and need cleaned .
The best way is to remove it but if you pull the blower motor and you have a air compressor and a nice long air gun you can sometimes blow it out.
Be careful and not bend the honeycomb closed.

...and the good tips keep on coming :thumb:

s14sh3r 11-03-2012 08:06 PM

I just tried it and it flows significantly less switched to warm. Like, it flows as much on cool and low than it does on warm and high. I know what I'll be doing first chance I get.

jeepsrgreat 11-04-2012 01:44 AM

I'll be checking this tomorrow. Hope this tracks down the problem.

Fireaxe 11-04-2012 03:08 AM

Subscribed until we get heat!

humpaco 11-04-2012 06:27 AM

I'll try the defroster test today but one bit of information I forgot to add in my original post was that I noticed if I have the fan set on the lowest setting there is decent hot air coming out of the vent. But the higher I turn the fan the cooler the air gets. Is that also symptomatic of a blocked/dirty core? Or an issue relating back to a clogged fresh air intake?

I'll break out the air compressor today and see if that makes any difference. I will repost later with results.

Love this forum. You guys are great.

Jerry Bransford 11-04-2012 12:08 PM

Yep that makes me think the heater core just isn't putting out the heat it should. Did you flush the hoses too or just at the ports on the firewall? Maybe the hoses, though they are hot, just aren't flowing coolant well enough.

s14sh3r 11-04-2012 12:31 PM

When I flushed mine, I flushed the hoses as well. I'm getting ready to pull the Jeep up to the shop and pull the blower motor and take a look. I don't know how well I'll be able to see in there, but if there is any debris I'll take a pic and post it.

div4gold 11-04-2012 01:00 PM

Jerry might have the answer to this: I was wondering if the heater control valve wasn't opening all the way if you would get the symptoms described?

s14sh3r 11-04-2012 01:34 PM

Well, here's what I found when I pulled the blower motor:

http://i.imgur.com/mX2wS.jpg

Here's after I blew it out best I could:

http://i.imgur.com/ThCzA.jpg

I haven't put it back together yet and there are some other things I need to do before I can run the heater to see if it's improved, but I'm betting there's an improvement because a good 25% of the core wasn't allowing airflow through it. I'll post results later.

dixau11 11-04-2012 01:37 PM

I was about to go through that whole process, but then realized my heat cable wasn't working, reached down and
Pulled the lever. Boom heat!! I was happy..

s14sh3r 11-04-2012 03:51 PM

It now gets uncomfortable to hold your hand over the defrost vents. I wish I had a thermometer to check the air temp at the floor vents as per the FSM. I did grab one of the wife's candy thermometers and put it on top of the defrost vent and got 125 degrees. The ambient temp is 70 degrees. The specs are for the air temp at the floor vents with the engine at operating temperature to be 147 degrees. Without a proper thermometer, I won't be able to tell if it's within specs, but it's blowing pretty damned hot, so I'm happy. Now to see how it does in the cold :thumb:

572 11-04-2012 04:28 PM

s14sh3r...What year is your Jeep?

I was just wondering if you had to remove your blower motor from under the hood (behind the battery) or from inside the Jeep? I think they changed where you access the blower motor sometime around 01 or 02.

I think I may need to clean my heater core like you did and it looks like you had decent access to the heater core.

scott howard 11-04-2012 05:26 PM

This preston flush kit works very well and cost only around 15 dollars.
And the preston radiator flush and cleaner chemical will remove an unbelievable
extra amount of rust and corrosion that a water back flush can not remove and it only cost 6 dollars.
I install these flush kits on all my Jeeps and do a back flush every 3 years.
The whole labor time to install kit and do a flush is 20 minutes.
If you do this and pull the blower motor and clean the outside of your heater core with compressed air you will have heat like when it was new.

humpaco 11-04-2012 06:36 PM

Jerry, I I flushed through the firewall only. Good suggestion about the hoses. Will do that this week.

humpaco 11-04-2012 06:46 PM

Quote:

Originally Posted by scott howard
A easy check to see if your heater core is stopped up with dirt on the outside and not letting the air flow thru it freely to transfer the heat to the ducts of the Jeep is to set it on defrost and temp on cold and feel how much air is flowing . Now switch it to Hot and see if it loses a lot of air flow( it will be a little less just because it has to blow thru the core but it should not be a lot less ) if so your core is clogged with dust and dirt and need cleaned .
The best way is to remove it but if you pull the blower motor and you have a air compressor and a nice long air gun you can sometimes blow it out.
Be careful and not bend the honeycomb closed.

Scott, I get the same airflow through the top vent on hot and cold so it doesn't sound like a clogged/blocked core. (right?)

Also, I removed the blower motor to see if i could gain any kind of access to the core to blow it out with compressed air. I have a 2002 so it is removed from under the dash rather than under the hood behind the battery. Couldn't see or feel the core so couldn't really do too much.

I'm out of ideas at this point. Any other suggestions?


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