[AZ Jeff]

ZOMFG this looks like a royal PITA. I'd just assume drive around with no heat than go through all that garbage. What a crock...

Unless you live in the part of Indiana down by the Ohio River, I bet you change your mind in about January, when you are scraping ice off the INSIDE of the windows due to lack of heat.

I have been in that position (due to a PLUGGED heater core), and let me tell you, it's NO fun.

Living without AC is feasible. Living without heat (in the northern 2/3 of the US) is pretty much impossible in the winter.

 

[AZ Jeff]

Why did you change the accumulator? Was there something wrong with it, should it be changed for some reason? And lastly if you change both you said to put in 6 oz total of oil? My A/C leak too and they say it's the Evap. but I have yet to work up the will/care/decide to start doing something about it.

it's considered wise practice to replace the accumulator (with it's dessicant) any time you have the system opened up for long periods such as when replacing major components.

 

[AZ Jeff]

I'd like to know the answer to this one as well. Does anyone know? I'm in the market for an XJ, and if the 96 and earlier were easier to put a heater core in, it may influence my decision.....

The Pre-97 heater core R&R procedure is pretty much the same as that for the later models.

 

[AZ Jeff]

Thinking about attempting this...you guys mentioning replacing a couple of onces of oil to the system...where do you put this in at? Pour in the evap core???

Thanks.

Yes, pour the required amount of refrig. oil into each part you replace;

Component --fl oz
A/C System -- 6.1
Accumulator -- 3
Condenser -- 0.75
Evaporator -- 1.5
Compressor--drain and measure the oil from the old compressor as noted

 

[AZ Jeff]

So was doing the install this weekend and had the hvac box taken out and installed the new blower motor, the evaporator, then proceded to the heater core. I soon found out that i was sent the wrong heater core. Sent message to jeepair.com, waiting for reply.... Kinda pissed as this is my daily driver
Can the original core be reconditioned by ac/ radiator shop?

Yes, it can.

 

[AZ Jeff]

just curious and im pretty sure its my evaporator but want to be sure.....

2001 Cherokee Sport

previous owner just replaced the compressor and canister on the fire wall whatever its called. Professional a/c guy/family friend found no leaks around the lines or anything. have tried to recharge twice and it blows cold but then leaks out damn near immediately. also smell refrigerant in the car after recharge with the A/C on full blast. we then noticed the evap drain coming from the firewall is leaking a green fluid, almost like coolant but has more of an oily texture rather than coolant from the heater coil, also does not smell like coolant so im suspecting PAG oil? does this sound like an evaporator issue? If so should I replace the heater core while im in there? any other ideas? Blows cold for the few minutes it holds a charge......

Replace the evaporator AND the heater core, while you are at it.

 

[AZ Jeff]

lets get a group together and kick the engineers a** that thought of this genious design. Im a sophomore in college and i did this and then went to my computer and designed a better system. that says something about the engineering here.

Don't automatically blame the engineers. Product development is a collaborative effort, and maybe OTHER people besides the engineers dictated the way the design worked out. Perhaps the accountants placed a cost limit on the design that prevented the engineers from including an easy way to remove the evaporator.

When I was in engineering school, I felt the same way as you. Then I got into industry, and found out what REALLY controls the way a design turns out.

 

[AZ Jeff]

ok another question: anyone have any tips on how to reconnect the hose from the condenser to the evaporator? the one from the accumulator snapped right in, but this one is being a real PIA! how do i twist it in if i cant move the hose?

You are talking about the high pressure hose with the orifice tube contained therein? If so, jus lube up the o-ring with refrigerant oil and press it together.

 

[AZ Jeff]

My turn to rip my dash apart for this repair came last week, only I did not have evaporator issues. Instead, my heater core was leaking. I took no chances--I replaced both the heater core and the evaporator.

Thanks to "99GreenMachine", who sold me the foam gaskets, my heater box bolted right back up tight to the firewall.

A couple of tips for those contemplating this job:

1. have some spare 1/2 inch thick self-adhesive weatherstrip tape around. You will need this to seal the heater core and evaporator where it slides into the heater box.
2. have some 1/4 inch thick weatherstrip as well. You will need this to seal all joints where the blow-molded air duct sections slide together.
3. buy some self-adhesive felt sheet, and cut pieces to fit whereever two pieces of plastic join each other in the dash. This will avoid squeaking once assembled.
4. the driver's seat does not have to come out, nor does the steering column need to be totally removed. Just push the seat all the way back, and drop the column on to the seat.

It took me about 3 hours to get the heater box out of the vehicle, following the procedure in the FSM. I spent the next 3 hours cleaning the heater box to get rid of the dust and mold inside. Then I found out the heater core I bought on line did not have the correct bends in the copper pipes feeding into it! That stopped my reassembly for the night. I would up getting a core at NAPA the next day instead.

Final dash assembly and coolant flush and AC recharge took me about 4 hours. I went carefully making sure that all the plastic bits snapped together and/or screwed together with the right foam or felt insulators.

I think the AC is working OK, but it's a bit cold (even here in Phoenix) to tell if I am getting the correct pressures. The pressure chart in the FSM does not go below 70*F, so I had to guess.

 

[AZ Jeff]

Hmmm well ill have to try that. Is this the same hose that you have to drill out a section of inner fenderwell to get to? Not sure how to shoot air in that, I did do the hole at the base of thhvac though....sorry for spelling, I'm on my phone lol

No, the evaporator drain hose faces forward out of the firewall and drips directly onto the "frame" rail inside the engine compartment.

 

[AZ Jeff]

Im lookn to do this soon. Where do you get the foam piece to go between the firewall and air box? Is that a dealer part?

It's a dealer only part.

You can probably cobble-up a decent substitute using the self-adhesive foam used in window air conditioner installations.

 

[AZ Jeff]

Hey guys any inPut on the price difference and can I just do the heatecore. That way I don't have to worry about evacuating AC???

No, you cannot change the heater core without removing the heater box. Removing the heater box requires discharging the AC.

 

[AZ Jeff]

Actually, two more questions: The OP'er showed a picture of a huge chunk of foam that was UNDERNEATH the evap core, between the core and the bottom of the housing, as it appeared in the pic. For you guys that have done this (especially you, AZJeff), what did you guys use as a substitute for this chunk of foam? Any pics?

WHat did you guys use for foam sealer on TOP of the two cores, once there were set down into the bottom of the housing?

The OEM seals for the evaporator core are styrofoam. If your originals are shot you can make replacements from chunks cut from a cheap cooler.

 

[AZ Jeff]

Good idea. Couple more things Jeff (or anyone):

2) I'm not replacing my compressor, just evap core and accumulator. Is it necessary to add PAG oil to my evap core and accumulator...since my compressor probably still has all of it's oil, and since I will have to have the system vacuumed before charging? If necessary, how is it put into the accumulator..........?.

Oil needs to be added to each component you replace. 3 ounces in the accumulator, 0.75 in the condenser and 1.5 in the evap. Just pou it into the ports brforebinstalling.

You MUST evscuate the system snf HOLD a vacuum for 30 minutes before refilling with refrigerant.

 

[AZ Jeff]

I did this job last fall with the help of this write up. It is starting to smell inside the truck again so it looks like its time to do it again. :-(

Anyone know how makes the most reliable replacement core? I don't really care about warranty because I'd still have to pull it out to cash in.

I got mine at NAPA because the ones at Oreilly and Autozone were not the correct shape to fit.

 

[AZ Jeff]

Did anyone create a PDF of this while the pics were still available? I found one old link to a PDF of this, but it was dead.

I have it. PM me with your email address, and I will send it to you.

 

[AZ Jeff]

Three questions,how long did it take you? 2 was it a real pain in the ***? was it worth it to go through this ordeal?

It sort of depends on your level of experience. I have been working on cars for 35+ years, and have tons of tools of all types.

While I was at it, I replaced all my coolant hoses while I was at it, plus my heater core as well as evaporator. I also put in all new foam seals on all the ductwork for the heater box. When I reassembled the dash, I put all new felt anti-squeak pads between the pieces as I reassembled it. I also evacuated and recharged the AC system myself.

t took me approx. 10 hrs of actual working time to do it over a weekend, and I spread it out over 2 days, since I was not a big hurry to get it done, as I was doing it in my garage.

If you are less experienced, or you have fewer tools, it may take longer.

I had no choice in fixing mine, as the real reason I went into it was because my heater core was leaking. I less than perfect cooling system on an XJ in Phoenix is almost certainly fatal to the vehicle!!!

 

[AZ Jeff]

You dont really need any special tools, average set of tools should take care of it.

I found a 10mm ratcheting box wrench made getting the nut off the stud holding the heater box to the firewall behind the cylinder head invaluable.

Most guys don't have ratcheting box wrenches, but it's a worthwhile addition for this project.

 

[AZ Jeff]

Can you tell me were the write up is for replacing the Heater core. thanks.

The link is posted in message 321 in this thread, just above your first post.

 

[AZ Jeff]

Any idea how long it would take somebody with medium backyard skills? This looks like 8-12 hours min to me if i break nothing

That's a fair estimate, maybe a bit longer if you don't have lots of experience at this type of thing.

Also, this is not a job you want to take on out in the driveway. YOu need an enclosed space for this job so you can organize your stuff and keep it out of the elements.