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Leaking Heater Core

riverside

NAXJA Forum User
Location
Riverside CA
I need to replace the heater core. Looking to get a copper one, but what I need is some insight/experience on this project. Procedures, involvement, Do's and Don'ts, etc, thanks. youtubes?
 
Replace both the heater core and the A/C condenser. For a first timer, plan on 4-6 hours to pull the dash, and 2-4 hours to reinstall it.
 
Good news (I think!)
Due to the recent rains I have determined the water on the floor is due to a body leak, not the heater core! Whew! Where would you look first?
 
Good news (I think!)
Due to the recent rains I have determined the water on the floor is due to a body leak, not the heater core! Whew! Where would you look first?

What year?

Common water leak for 97s and up is through the firewall opening where the blower fan pokes thru. The foam seal between the HVAC box and the firewall deteriorates over time. Pulling the dash gives you access to the foam seal. Pain in the ass though.

Easier fix is to apply silicon sealant around the mating area where the blower pokes into the engine bay. I did that fix about 8 years ago, and it's still holding. Also, move the harness a bit, just above the blower. Water tends to drip off that harness, straight into the blower area.
 
Replace both the heater core and the A/C condenser. For a first timer, plan on 4-6 hours to pull the dash, and 2-4 hours to reinstall it.



It’s the AC Evaporator you want to replace with the heater core. The condenser is in front of the radiator.
 
What year?

Common water leak for 97s and up is through the firewall opening where the blower fan pokes thru. The foam seal between the HVAC box and the firewall deteriorates over time. Pulling the dash gives you access to the foam seal. Pain in the ass though.

Easier fix is to apply silicon sealant around the mating area where the blower pokes into the engine bay. I did that fix about 8 years ago, and it's still holding. Also, move the harness a bit, just above the blower. Water tends to drip off that harness, straight into the blower area.

Mine is a 92, now that I look more closely, seems at the windshield seal, but not sure.
 
The HVAC Box-to-Cowl seal can be a problem in the earlier models, I had that very issue on my '92 back in 2008...
 
My heater core was disconnected when I first got my XJ.
I literally gutted my XJ, and redid the interior, and in doing so rebuilt my whole HVAC system.
My passenger side floor pan was pretty rusted. Determined to put a stop to any future rust after fixing it, I was set out to find ALL the leaks.

Like posted above most of the water leaks you will find in your Jeep will come from the seals between your HVAC system (fan, Freon/water).

Take a look at the firewall pad in the pictures. You can see the places on the foam where there were leaks on the firewall.

img_1629_01a7aa967163fe873859e32050dc8523b2693e50.jpeg



img_1563_8f3f1cadb960db4c1cc1afcd1f9311b91ab7c667.jpeg



It was also leaking a bit around the drivers side too.
I ended up sealing around these grommets with some silicone. There was one hole in the firewall, that did not even have any kind of plug on it from the factory?

img_1630_ef1cb1d38719cde6bdfd5a7f54dafbd03e448071.jpeg
 
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