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Discussion Starter · #1 ·
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.
 

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

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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.
 

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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.
 

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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.
 

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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.
 

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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.
 

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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.
 

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Discussion Starter · #13 ·
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.
 

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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.
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:
 

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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.
 

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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:
 

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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.
 

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

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Discussion Starter · #20 ·
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.
 
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