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War Pig 0811 11-04-2013 10:19 AM

Heater Core or Blend Door...Which one?
A few months ago I observed when the A/C on, hot air would blow out of one side of my vents and cold air from the other side. This happened only occasionally.

Now, not being new to this forum and after doing much reading I determined that my jeep is just another victim of the broken blend door problem. Simple enough to fix. Planned on doing the repair myself (without dash removal) over my upcoming vacation. But now something else has me puzzled.

Just this past week, after about five minutes of driving, my glass completely fogs up. Heavy fog pours out of the vents, and the A/C and fan control seem to not respond at all. This happens every time I drive it now. I do detect the slight, sweet smell of anti-freeze. No leakage in the floorboard.

So back to the forum I go and decide that my Jeep is now showing symptoms of a bad heater core. BUT, I am wondering if the fogging problem could be a symptom of the blend door issue, or is it just a weird coincidence that BOTH things go bad at nearly the same time. I couldn't find any posts here with anyone complaining about both issues at once.

Just wondering if I should even bother with doing blend door, without dash removal and see if it works OR man up and pull the dash and replace the doors AND the core. Trying to save time and especially money. Many thanks!

gold01wj 11-04-2013 11:11 AM

If your trying to save time and money in my opinion pull the dash and do it all at once. If you smell anti freeze and have fog your core is likely bad. It won't always cause a wet floor because the carpet has a rubber lining on the bottom. You can pull the sill plate on the passenger side and pull the carpet back and inspect for coolant on the floorboard. Do it right if the core is leaking. Wjjeeps has a good dash removal/blend door replacement writeup by the way.

War Pig 0811 11-05-2013 08:10 AM

Thanks for the input. I'm not looking forward to doing this. :fear:

Starboard M 11-05-2013 01:11 PM

Just replaced my heater core and blend doors last weekend! Its fun.....

While I wasnt having issues with hot and cold air, my windshield was fogging up when the defroster was on. Was also fogging just while driving.

I do not have a sense of smell, but I asked several people if they could smell coolant and none could. Carpet was not wet at all.

The core was in fact bad, and had pooled coolant in the box. There was also some moisture under the carpet, but apparently not enough to leak through.

Took me about 12 hours, over the course of two days. Was not all that complicated and didnt require any special tools. Take your time and it should go smoothly.

gold01wj 11-05-2013 01:12 PM

It's pretty easy even if you are mildly mechanical. It's all done with simple hand tools. The biggest pain it getting the heater hoses of the core. It is still manageable. It's definitely time consuming but it is pretty easy.

oldfamilyguy 11-05-2013 03:50 PM

It would not be unusual for both to be bad. myself and many suggest replace the recirculation door (also prone to failure)while you have it apart. Not much extra cost

War Pig 0811 11-06-2013 04:39 PM

Thanks for all the input. I'm just going to pull it all and replace everything and be done with it. I hate doing things twice. Taking it out doesn't worry me...puting it back in correctly is another matter.

gold01wj 11-06-2013 04:43 PM

Follow the wj jeeps write up exactly and you will have no problems. You will likely need an assistant for 5 mins when removing and installing the dash assembly FYI. It's a pretty easy job mechanically just time consuming.

War Pig 0811 11-06-2013 04:50 PM

Thanks. I'll let you know how it went.

link375 11-13-2013 03:07 AM

if you haven't done it yet, here's a video I made on how to take the dash out and replace everything.

all the parts you need are listed on the video description

sage39henry 11-13-2013 08:37 AM


Originally Posted by link375 (Post 17663505)
if you haven't done it yet, here's a video I made on how to take the dash out and replace everything.

all the parts you need are listed on the video description

Yes follow a video, makes your life way easier. Although, link makes it look about 10x easier in some spots lol. It helped a lot though :highfive:. On a side note, it took my floorboard a while to get soaked in coolant before i ever realized it. I checked and checked and never felt or saw any, even though I was smelling it. Went out one day looked and BAM coolant pool under my carpet. :thumbdown:

Vejito 11-13-2013 09:16 AM

Gonna try this tomorrow. Hopefully I can do it in one day cuz the dub is my dd. I have to work Friday but worse comes to worse I can ride my Suzuki for one day. Will be a cold *** ride tho

gold01wj 11-13-2013 11:33 AM

As long as you have the parts all together and dont break anything important taking it apart a day should be enough time. Good luck getting the coolant out of the carpet...mine has a plastic drain plug in the floor that I poped out. it helped get the majority of the original puddle out but I'm still trying to get it dry down their. I did mine about a year ago. The top of the carpet is dry but the plastic lining on the bottom had a tear In it that absorbed a bunch of coolant... I'm trying to get it dried out before the floors start rusting. :brickwall

Vejito 11-16-2013 09:52 AM

Finished my heater core swap. Real pain in the rear. Could have used another set of hands re-installing the dash but got it in anyway. No more mystery mist coming from the defrost vents

The time now is 07:06 AM.

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