I put my HVAC box back in the 96 XJ, hooked up the battery and started it up.

No heat and there is coolant leaking out of the HVAC box after installing a new heater core. This is killing me after struggling to put that da#n box back in.

Is there anything else that could cause the coolant leak and lack of heat? Could the new heater core really be bad out of the box. Either way I'll have to take it apart but if you guys can think of something else besides needing a new core...again. Man this is frustrating..

 

From where is it leaking? If its around the heater hoses, the clamps might be a tad loose, or the tubes were tweaked just enough to crack the joints. Coolant can leak down the firewall, or inside the cabin. Or both. No heat could be the blend doors not opening for whatever reason. Still using a heater control valve?

 

I got rid of the HCV. I should check and tighten the clamps on the heater hose, I didn't really crank down on those yet. I had to take off so I won't be able to check for a couple of hours.

I could also see the tweaking of the core as something that went wrong. I don't know how these things can't be tweaked when putting the core back into the box. And then when sticking them through the firewall and the foam gasket and lining that stuff up. I would hope there would be some flex avaialbe.

 

So when putting the heater core back in the box and putting things back together, do you have to be somewhat gentle with this thing? I managed to take apart the dash without breaking any plastic. And in the write ups I didn't see anything mentioned about this being a problem with the heater core. I just can't believe I got a bad core.
Just double checking as I can't imagine doing this a third time.

 

As mentioned above it could be the hoses not tight enough at the firewall. Loosen them and pull them away from the firewall some to where you can see a bit of the heater core tubes before tightening them.

As far as no heat check that the cable on the blend door lever is working as it should. No vacuum hoses involved with our 96's.

 

I'm crossing my fingers on the heater hose option. Will be home later this afternoon and will update.

After the initial frustration I've mellowed a bit and will redo the job with a happy face if that's what happens. I bought this Jeep for fun and to learn more about cars so I guess this is just part of the deal.

 

I sure hope that tightening the hoses solves the leak. Hate to think you got a leaking heater core right out of the box. First junk rebuilt steering gear boxes and now this? Sure hope not.

 

fb97xj1 and EZEARL. Your advice might have saved me a bunch of time and heartburn, can't thank you enough. When I got home I pulled back the heater hose going into the core and tightened it up and ran the Jeep for about 15 minutes and NO LEAKS! And I had hot air as well.

I had the hose pushed all the way into the firewall so you guys had it right with your advice about pulling the hose back a bit.. I'm hoping running it for 15 minutes was enough to say this heater core replacement was a success but I think I will run it again tomorrow to confirm. I'm hoping to button up the dash and put everything else back and call this job done. I'm looking forward to an "easy" job like a ball joint replacement or something like that.

Thanks again guys.

 

GLAD it worked for you. I've seen that quite a few times over the years.

 

Well, it was the crappy chinese Spectra heater core that failed. Brand New out of the box and all put together and it leaked. It failed where the output pipe meets the core. Here's a picture and you can see the gap. I'm sure it got that way when I was adjusting the pipe to line up with the bracket and screw. QUESTION: Does MOPAR make a heater core? I've got a buddy that works at the dealership so maybe if I get his discount the price won't be completely horrible.

2nd question: do you think I could solder that gap and make a good seal?

 

With the proper solder and flux you can fix it, but you'd be wise to put some type of heat sink on all the areas close to it that have solder. In my line of work we use a gel type heat sink that comes in a spray bottle. Such as this:

 

TCP64, thanks for advice. I'm a complete novice with this type of thing. Would this require some sort of skill to solder? Also, would you mind explaining "sink"? I can bring this back to NAPA for a new one but I'm sure I'm going to get another piece of crap. Just wondering if it's better to reinforce this broken one as the factory solder job looked really weak.

 

If you have no soldering experience then your best bet is to take it back to NAPA. NAPA usually sells good stuff in my experience. Open the box while your there and inspect the solder joints of the new coil. If one of the salesmen have any experience they should be able to tell.

 

Shouldn't be a problem returning it. Did notice on the Napa site that the warranty is only for 1 year.
There is something wierd at the Napa site I did notice.
Now I am going by the '96 in your profile.

https://www.napaonline.com/en/search...Qualified=true

Notice how one says aluminum and one says copper and brass?
Picture does not look like copper and brass but it could a "for illustration purposes only" thing.
But also that it is cheaper?
Gotta wonder about that.

 

Now I'm looking at a Carquest Core that also says it is Brass and Copper.Here's the link:

https://shop.advanceautoparts.com/p/...021%7CL3*15934

I bought the NAPA core a month ago so returning is no issue. Just don't want another crappy one. I'll probably go with the Carquest and see if I have better luck.

Here are the specs from the Carquest core:

Core Height:8 in

Core Material:Copper

Core Width:7.5 in

Inlet Pipe Diameter:0.625 in

Outlet Pipe Diameter:0.75 in

Tank Material:Brass

Thickness:1.25 in

Tube Material:Copper/Brass

Universal Or Specific Fit:Specific

We'll see.