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Coolant leak / Heater Core

GamblySmurf

NAXJA Forum User
Location
Denver, CO
Hey guys.

I'm certain that I need to replace the heater core in my XJ, it's bad enough that you can see vapor coming in to the cabin through the vents when it's running. It has a developed a significant coolant leak, it drips down mostly through where the passenger side control arm attaches. Is this likely coming from the heater core leak, or do you think there's another leak in the system.

I'm willing to try to tackle the heater core, but if there are other leaks, I'm not sure I really want to try to fix this.
 
Heater core is easy to fix, getting to it is easy too just tedious -- If you're willing to tackle a heater core replacement everything else is simple

Mist in the cabin is heater core -- fix it or bypass it -- bypass sucks in snow, can't defrost your windows
 
Yeah it sounds like the heater core is shot. Is there coolant under the carpet?

I agree this is an easy job, don't let it bother you. Anyone with a wrench can do this.

Luckily weather's been good lately, hop to it sooner than later, driving in the winter with No heat and foggy windows sucks.
 
Yeah it sounds like the heater core is shot. Is there coolant under the carpet?

I agree this is an easy job, don't let it bother you. Anyone with a wrench can do this.

Luckily weather's been good lately, hop to it sooner than later, driving in the winter with No heat and foggy windows sucks.

No coolant under the carpet. Just coolant vapor coming in through the vents.

There is a significant leak externally, and wherever it is originating it can seen dripping out around where the passenger side control arm connects.
 
No coolant under the carpet. Just coolant vapor coming in through the vents.

There is a significant leak externally, and wherever it is originating it can seen dripping out around where the passenger side control arm connects.

Normally that port is for your evaporator core to free up condensation. Its leaking good if its coming out there. Your lucky its not under the carpet this far, just a pain to clean.
 
Getting to the heater core is easy (just tedious) once you know the trick - essentially you drop the steering column and loosen the dash and swing the passenger side out. There are some videos on YouTube that will help you with that.

You must discharge and disconnect the A/C lines at the firewall so be aware of that. You can pay a shop to remove the R134a and refill it when you are finished if you don’t have the tools. I’d replace the A/C accumulator and orifice line as a part of this job but that’s up to you to decide.

Getting the heater box apart is a bit of a challenge but just take your time and locate and remove all of the screws and don’t break anything.

You might go ahead and replace the A/C evaporator core while you are replacing the heater core to avoid having to do the job over again later.

I took my time and replaced my heater core over a weekend so that’s about how long it takes.
 
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