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99 Cherokee AC Leaks Freon

XJOutsider

NAXJA Forum User
Location
Landenberg, PA

I recently replace the Compressor on the AC my 99 Cherokee with the 4.0L. I vac the System out for 1 hr and then let it sit for an hour.

The gauges did not budge so the system should be sealed properly I assume. The system was charged to the appropriate pressure. The AC blow Ice cold. The accumulator and lines going into the evaporator and the lines coming out have heavy condensation on them.

The system only hold the charge for about 4 days them the gas gets low and the compressor will not kick on again. I have used the UV dye and special Light and glasses I have no leaks under the hood. I used one of those sniffer detectors’ too and I not coming up with any leaks.

Is it possible for the evaporator to get to cold and cause a leak? Every once and a while you do get a wif of Freon in the car when the ac starts

Any help would be appreciated
 
The evaporators are known to be a source of leaks due to stress during installation and rubbing after years of use.
Remove the glove compartment door and the access cover to the evaporator and search for leaks. You may see signs of oil accumulation on the tubes and the evaporator cover.
 
Agree with CharlesS, check the evaporator.
 
I just had lots of work done on my a/c system. Took 4 trips to the shop before it now seems to be holding a charge. Finally turned out that the culprit was the evaporator. The system would hold a vacuum even though the evaporator was leaking. Try using the sniffer in the condensation drain tube and see if it detects anything there.
 
Thanks for the the replys. Is it possible to remove the Evaporator with out removing the whole asembly for the vehical. The FSM say to take it out of the vehical As posted above you can access the evaportor by removing the glove box and a cover. I there enough roome to change it out like that.
 
Sorry my friend but changing the evaporator is a big job and u have to completely remove the dash to do it. I just did mine recently because I had basically the same prob as you. If you follow the FSM closely and are mechanically inclined like most of us on here, you can save yourself a huge amount of money. None of it I found to be particularly hard, but there is alot involved. There are several write ups on here on how to do it, with pictures and everything. Some things I will add are:

1. Remove your front seats.
2. Buy the a/c line disconnect tools and new o-rings
3. Replace the receiver/dryer unit
4. Remove the steering column as a unit. Do not remove
the steering wheel and airbag. You can take the whole
thing out as an assembly.
5. Buy a swivel head 11mm gearwrench. You'll thank me
when u need to get the last bolt holding the heater/evap
housing (its on the firewall behind the engine).
6. Bag and label every bolt
7. replace your heater core while u have it apart.
8. Take your time and grab someone to help u when u r about to
pull the dash.
9. Good luck and Godspeed my friend...
 
Well it off to the shop on the way home to have the systme evacuated. So I can start this job this weekend. to bad it going to be in the 90's this weekend. I have heard this is a 10 to 12 hr job
 
Wait. You're saying that some late model XJs did NOT leak freon? I thought leaks were standard from the factory!

Yep late-models are a bear to do... count on dropping the dash. There is a hacky redneck way of doing the evaporator on a 96 or earlier without dropping the dash but they "improved" the design on 97 and later.

Careful with the steering, you don't have to actually pull the steering wheel just drop the steering column and wheel down and angle the dashboard out. If you disconnect the steering column from the steering box make sure you recenter the clockspring before reassembling or you will be replacing that next.
 
I just did my '97 XJ. Before pulling the dash I disconnected to lines at the firewall to the evaporator then put some Saran wrap on the larger tube and pressed my thumb hard on the opening and connected my large tapered adapter to my hand vac to the smaller tube. The evaporator would not hold vacuum. Using the same method with the new one my work bench it held vacuum.

My heater core was also leaking. You might want to replace yours too. This is not a job you'll want to do twice.

I pulled my dash out completely because I had a bad leak at the lower left of the windshield. I was then able to pull out the carpeting and power washed it on the driveway and do some floor rust repair/paint/insulating.

With the center vent blowing 38 degrees on a recent hot/humid day I'm glad I did it.
 
I'm just commenting on one of the above posts, I have heard you can drop the steering column out of the way, but I found the whole job was much easier removing it altogether. I made sure I kept the steering wheel straight when i removed and also when the steering wheel/column assembly was laying on my garage floor. It really wasnt a big deal at all to remove it. Not sure on the amount of hours it will take you but i did it over the course of a few days as I had another car i could drive for the time being. Good luck and if you have any questions don't hesitate to ask!!
 
Can any one tell me what the Foam seal from the box to the firewall is made of. Also is it a dealler only Item.

Mine was really ratty. It allowed debris to enter the box. I went to a women's craft store and bought some high density foam, one inch thick, used the original as a pattern, then placed it against the lines and made small slits and pushed the foam over the ends so it stayed tight. After I liked the way it fit I took it off and sprayed it with Bumper Black paint (it's flexible). It took several coats before it looked OK.
 
Tape your steering wheel together so it doesn't spin freely... you will break your clock spring which will take out your airbag horn and cruise control a super annoying mistake that is easily made.

I did this whole opp alone on my 99 twice now and the second time took me about 4 hours

You DO NOT have to remove the seats!

Also buy some rtv so when you put the fan motor back on and put the boX back together you make a nice tight seal.

And finally make sure all your blend doors etc are lined up before putting it back in.
 
I wouldn't use that stuff, it's stiff and crumbly and open cell. You'd want a more flexible, closed cell foam.
 
I'm just commenting on one of the above posts, I have heard you can drop the steering column out of the way, but I found the whole job was much easier removing it altogether. I made sure I kept the steering wheel straight when i removed and also when the steering wheel/column assembly was laying on my garage floor. It really wasnt a big deal at all to remove it. Not sure on the amount of hours it will take you but i did it over the course of a few days as I had another car i could drive for the time being. Good luck and if you have any questions don't hesitate to ask!!

I'm putting mine back together after replaciing the evaporator, and I'm having a helluva time getting the steering column back on the 4 mounting studs. I've looked all over the place and haven't found a single comment indicating that this is hard to do, so I must be missing somethinig very obvious. No problem mounting it onto the horizontal studs, but when I do that the vertical studs miss the holes through the top plastic piece by half an inch. What am I doing wrong?

I hate hemorrhaging time to stupidity!
 
dalitton , if you are still around- how did you solve this? looks like I'm having the same problem. And did you take out any other bolts to drop the column down?
 
dalitton , if you are still around- how did you solve this? looks like I'm having the same problem. And did you take out any other bolts to drop the column down?

That thread is 7yrs old and he been here for 5yrs!
 
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