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Unread 11-26-2013, 07:15 PM   #1
mrcangi
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Wj low heat problems 01 GC limited-4.7

Hey guys im new to this board since I am sort of new to jeeps. Looking forward to all the help here. Well to start my 01 4.7 limited heat is not any were hot enough. The motor was just rebuilt and put back in about 1000 miles ago. Broken valve seat causes alot of damage! It has a new water pump and thermostat.the radiator is only about 2 years old. Was put in by previous owner with receipts to show. I've double and triple checked the level and made sure there no air in the system. Ive back flushed the heater core and it seemed to flow pretty good both ways I flushed it. I didn't see any debris come out when I did flush it. I've checked to make sure the blend door accuator is moving right and that seems fine. Both heater core hoses are hot. Hot enought that you cant touch them more than a second or two. I didn't really feel a temp difference in eaither hose they both pretty much felt the same. But my hands were pretty much froze also. Ive noticed in the last couple days its had a drip from the passenger side of the radiator. I haven't been able to tell if its the lower hose since it still has the stock hose clamps on. Its been pretty cold here so I haven't climbed under it to really look. It does not over heat at all. The needle runs just a tiny bit under 1/2 way. Or straight up and down. The level hasn't gone down that ive noticed but I only drove it for like 30 minutes today. Im lost on what to do. Heater core plugged? Broken blend door? Ive looked in the radiator while it wqs warm and running and no bubbles but I also dont see in circulating? Should I be able to see it circulate? Any help would be great guys. It gets cold in Wisconsin!!

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Unread 11-26-2013, 08:02 PM   #2
rdkendrick
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If you are running with enough coolant (level stays around the full line on the jug) and checked the hoses to make sure they are hot, then I would believe that your heater core might be clogged. If it were the blend doors, I would think it would be happening to one side or another. It is possible they are both bad. If you are really desperate, you can cut into the HVAC box: http://www.blendorstore.com/tech_tips. There are videos on the internet that show you how to do this.
When you flushed your heater core, did you use the calcium/lime/rust removing chemicals? You could try that, but you'll be risking a leak in the heater core. If you are desperate, it's worth a try, I guess.
The other option is to remove your dash, and replace your heater core.

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Unread 11-26-2013, 09:34 PM   #3
mrcangi
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No I did not use any chemicals. Just my garden hose. I thought about trying CLR in it to see if that would help. I need to figure out what it is because it dont keep it warm enough to drive when its this cold out. I dont know what made the radiator start to drip eaither because it just started. Im gonna check to see if its from the clamps being to weak because there the stock spring type. I guess ill look into flushing the heater core first. See if it helps.
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Unread 11-27-2013, 08:33 AM   #4
mrcangi
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I did a AZC diagnostic and got code 55. Left temperature door travel to small. What does that mean?
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Unread 11-27-2013, 09:35 AM   #5
mrcangi
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Crazy question. What if I didnt put the heater core hoses on the same one they were hooked to before I took the motor out. The hoses were they connect behind the belt tensioner. Would that matter? I didnt un hook them from the heater core when I pulled the motor out. If they were backward on the motor would that matter?
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Unread 11-27-2013, 10:22 AM   #6
mrcangi
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I checked codes again and got 54 and 55 now. Last night it only showed 55. Is it my blend doors causing all of this? Anyone?
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Unread 11-27-2013, 11:34 AM   #7
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It does sound like your blend doors. I am not familiar with the codes, but you said you had good flow through the core when you flushed it and both hoses are hot so to me it is indicating a blend door problem. Good luck.
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Unread 11-27-2013, 12:22 PM   #8
mrcangi
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Thats sort of what I am leaning twards. I can hear them moving. I manualy moved the front one behind the glove box when I took the motor off and still the same. Yes the heater core seemed to have a really good flow when I flushed it. Today I did feel that the lower heater core hose coming out of the firewall was just a tad cooler than the top one. I guess maybe im going to have to cut into the heater box and check the blend doors. Go from there.
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Unread 11-27-2013, 12:26 PM   #9
rdkendrick
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Quote:
Originally Posted by mrcangi View Post
I checked codes again and got 54 and 55 now. Last night it only showed 55. Is it my blend doors causing all of this? Anyone?
Right AND left temperature doors travel too small: http://www.wjjeeps.com/climate.htm

You blend doors ARE bad. Go to blendorstore.com and, depending on the type of system you have, order the blend door kit.

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Unread 11-27-2013, 03:24 PM   #10
mrcangi
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I think im going to order the single door kit from blendorstore.com looks like a stronger kit than heater treaters. It dont bother me if the dual climate control works. As long as its warm! Before I do order them and cut into the heater box I want to make sure im going the right direction. It does blow heat from defrost and the vents. Both sides. Its just not very warm. Definitely not warm enough to be driving the vehicle when its cold. Most things I read about the blend doors is you get only cold air. Mines warm. Not cold. But not hot enough.

Last edited by mrcangi; 11-27-2013 at 03:36 PM..
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Unread 11-27-2013, 07:25 PM   #11
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Here is a post from a thread with a similar problem someone had back in February:

"I flushed mine just like the guy did in the video for the 4.0...
find your hot line, i un hooked my heater core lines by the radiator, i have a hose clip tool so it was pretty easy, got the top one (your hot) from the top of the motor and the return line, from under it... from here i drained what was in the core... now i got a fitting for my air compressor, wrapped electrical tape around that till it would fit snug into the heater core tube. hooked the air compressor up to this and blew out the line! once it was all i used some CRL and would fill the line, then lightly blow it into the heater core... let that sit for 2-5 min, then blew that out... (one thing i will add... when you blowing out the line if you do not re direct the return hose you will be blowing all that crap right out of the lines into the thermostat housing lines, so be sure you are directing that out, i shoved a hose into the return line and into my catch pan) after i got all the CRL out of there, i ran water through the lines till it was coming out clean and nice, again blow that out with the compressor... hook back up the lines... from here go start your truck, but leave the fan off and the heat on, add antifreeze till it is full, be sure you let your truck get warm so that the thermostat will open up and you can kind of burp it... then turn on the heat in the truck and the fans... worked great... i did see a video on your tube that said if you still dont have heat take the truck out and floor it, that will help... mine was blowing hot so i did this more to celebrate the heat! hahaha

if you have any questions let me know... took longer to get the hose clamps off and the lines off than it did to do the whole clean and flush. I did not take pics of this as the weather turned and temps dropped into the teens, and antifreeze was out and splashing around from time to time with compressed air so i did not watn to get that crap all over my phone and watned to get done sooner than later...

*jsut an update... it was only blowing warm air though, so i am goign to try to drain and fill the antifreeze as i have read that if you mix is off it will affect heat as well"

If that doesn't do it, then you should probably take it to a shop.

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Unread 11-28-2013, 08:50 AM   #12
mrcangi
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Well I already flushed the heater core out with my garden hose. It flowed fine both ways. There was no crap that came out of it. Once i flushed the anti freeze out it was clean clear water. Im gonna cut into the heater box first before I flush the heater core again. Thats why im on here trying to get advice on how to help it. Im not taking it to a shop to get ripped off. I can do the work my self faster and better than I would trust any shop. I just didnt know were to start but now I
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Unread 11-28-2013, 02:39 PM   #13
rdkendrick
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Quote:
Originally Posted by mrcangi View Post
Well I already flushed the heater core out with my garden hose. It flowed fine both ways. There was no crap that came out of it. Once i flushed the anti freeze out it was clean clear water. Im gonna cut into the heater box first before I flush the heater core again. Thats why im on here trying to get advice on how to help it. Im not taking it to a shop to get ripped off. I can do the work my self faster and better than I would trust any shop. I just didnt know were to start but now I
Well. Besides the blend doors, I am out of ideas. As far as flushing the heater core, the water may be clean, but is enough coolant flowing through the heater core for it to get hot enough? That's why the guy, above, was using CLR, to get rid of the lime/calcium/rust. I wonder if you can feel the heater core while you are in there, replacing the blend doors? It might just be a matter of flow. Good luck with it. I understand about not taking it to a shop versus doing it yourself.

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Unread 11-28-2013, 02:55 PM   #14
mrcangi
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Yea I mise well flush the core out with CLR. Its not going to hurt anything. Its just a pain when its cold out! Thanks for the replies and help guys.
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Unread 11-29-2013, 05:28 PM   #15
mrcangi
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Well today I cut into the heater box to look at the blend doors. Found out they both work good...but the "foam" on there was so old and crumbled that I dont thjnk they were sealing properly. So I pulled the front door out and cleaned it up and re foamed it. Couldnt get the back door out. Not sure if I had to cut the plastic more to get it out but I couldnt get it out. So I just cut a piece of foam to fit it and set it in there and closed the back door tight. Put it all back together and its definitely much better. Its plenty hot to keep the jeep warm now. Its not as hot as say my 02 silverado is but its a big improvement over what it was. Radiator sti seems to have a slow drip from sum were that I cant figure out... not sure if its coming from one of the seams or if its cracked... it dont seem to leak as much after if warms up? I dont know.. probably goin to just buy a new radiator and when I swap that out flush the heater core with CLR and a small amount of air.
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