'95 4.0L Sport A/C woes....RAWR! Linky to pics, any help appreciated.

[10-32]

Disclaimer - I have searched the A/C threads and got good info out of the responses to UcilXJ's thread (here: www.naxja.org/forum/showthread.php?t=58945&page=1&pp=15&highlight=A/C) however, something's still rotten in Denmark.

Background: 1995 Jeep Cherokee Sport, 2 Door, 4.0L HO, Auto, 4wd, 67K on the clock. Sat around for about a year and not driven hardly at all.

Problem: Breath of Hell A/C - I live in Tucson, AZ. 105 outside + Wind of Hades blowing in my face outta A/C vents not acceptible.

Steps taken: Scoured .org, bugged NAPA dudes, poked and prodded various fender-lizard acquiantances. Eye-balled little window with my A/C on and see the oft-mentioned "tiny-bublles".

A. I obtained (1) 19oz bottle Arctic Freeze R134a w/pressure gauge. I followed the directions on said bottle, to wit:

"1. Locate low pressure port and remove cap. Low pressure port is the larger diameter hoser unning between evaporator/firewall and compressor.

2. Start engine and set A/C to Max Cool. Connect charge coupler to low press. port. Check gauge. (reading 0lbs press at this point)

3. With engine running and A/C on Max Cool, shake can while holding upright. Press trigger to charge system. Relase trigger periodically the check pressure."

So...I did. I stopped and checked the pressure about every 30 secs. Finally, on the third check, I see that I am starting to to get close to 25lbs pressure. I continue. On the fifth pause and check...I see the needle drop back down to 0lbs.

I stop and check the temp coming out of my A/C vents....it's gone from Blast-Furnance to somewhere around luke-warm.

I wait a bit and see if the A/C cools down anymore. Nope.

I try again to charge the system, doing 2 applications of 30 seconds and checking the pressure. Still at 0 lbs.

Discouraged, I wave my hand infront of the vents to see if it's cool. Nope. I shut off the A/C and return to the can of R134a (still connnected to the port) where I discover the pressure gauge now reading at about 55lbs (Danger Will Robinson). I turn the A/C back on to Max Cool and check pressure. Now it reads zero. Repeat: A/C Off - Pressure 55 lbs. A/C on Max Cool - Pressure 0 lbs.

My A/C still blows luke-warm. Let it blow for 5 min while sitting stationary and went for a 15 minute drive in the early morning air while it was still cool (i.e. 88 deg). Nothing. The can of R134a seems about 3/4 full. The clutch is engaging. My little window is full of bubbles. I am perplexed to say the least.

Linky (or more accurately, URL-ly) to pics:

Pic 1 - http://photobucket.com/albums/y218/Shatner556/?action=view&current=Picture001.jpg

Pic 2 - http://photobucket.com/albums/y218/Shatner556/?action=view&current=Picture002.jpg

Pic 3 - http://photobucket.com/albums/y218/Shatner556/?action=view&current=Picture003.jpg


Soooooo...wtf? I know the refrigerant is in there. Been 6 hours now and I just checked it. Same. A/C off - 55lbs, A/C on Max Cool - 0lbs. No identifiable leaks. All I can fathom is that the line is somehow obstructed or plugged.


Fire at will.



10-32

 

[langer1]

A/C off pressure is normal, your doing everything correct accept turn the can upside down. It will also work the way your doing it but it will take much longer. When your system is full the bubbles will go away.

 

[RichP]

You probably have air in there, best bet is to go to a shop and have them evacuate the system and draw a vacumn then leave the vac on for an hour or so and see if it holds. If it does you can either have them recharge it or do it yourself. If you do it yourself you need a better refilling system. Get the hose kit and about 4 cans of dupont R134a, I'd get two big cans and two smaller ones.
Hook the hose up to the low pressure side and pierce the can lid with the hose kit according to directions. Turn the can upside down so the 134 is coming out as a liquid. It should suck it down in like 30 seconds or so. Then do the next can same way. Check the temp coming out of the vents with a thermometer, If you still see bubbles you might want to top it off with one of the smaller cans.
Another optio is to get a big bottle of 134 from sams club, about $50 or so last time I looked a few months ago, you will also need the full 3 hose w/gauges charging manifold. When using that setup I'd want a factory service manual at hand. Before my evap went south on my 98 I'd just recharge every few months with a small can and be good, now it does not hold it at all.

 

[goodburbon]

off pressure will actually be around 80 psi when full, remember the system equalizes pressure when the compressor is off, no more high/low side.

since the low side is actually where the compressor is sucking from, a low side press of 0 when the comp is on tells you that at least the compressor still funcions.

if you are basing the system charge on a low side pressure reading only, fill to the reccomended pressure while the compressor is on. should be~35-40psi

and, as langer said, hold the can upside down.

 

[10-32]

Alright guys...thanks for the info.

One thing....I did turn the can upside down, but it doesn't seem to be sucking any of the 134 out and into the system...damn can still feels about 3/4 full.

Refreshing to know that the off-pressure I'm getting is normalish.

Last question: being told that it is not possible for "shade-tree" mechanic (your's truly) to replace lines/o-rings on the system and that I have to have it professionally done. A/C systems and electronics are my only weaknesses....otherwise, if it's oily, I can fix it.


Once again, thanks.

 

[Lou]

Just in case....

Awhile my back my A/C crapped-out. Turn-out to be that the cable that controlled the Heat/Cold plenum flap had come loose -- at the point where the cable attaches to the arm on the flap(passenger area next to the tranny hump)

 

[old_man]

You will see a pressure buildup, the compressor starts, the pressure drops. Keep filling until the can is gone. It may take more than one can.

 

[RichP]

I never had any luck using the cans with the hoses already attached, maybe it's just me but the two or three I've tried over the years never seemed to empty out. On the other hand I have never had a problem with the seperate blue hose that has the can fitting on one and and the schrader type on the other. I bought one of those kits that had the hose and 5 big cans of R134, the hose had a pressure gauge in the middle of it, that sob never worked right either. The compressor would not pull it in, then basic hose on small can and right down it went. The kit was for either a full recharge of a 134a system or a retrofit as it had the little bag of fittings for the older R12.

 

[goodburbon]

get a vaccum pump and a dryer, and you sure can change the stuff yourself. I think some parts houses actually "rent" the pumps out, and the dryers are generally <$30

you're supposed to "re-capture" the coolant, and that is why they tell you that a shadetree can't do it. R-134 is supposed to be non hazardous to the environment though, and as such I dont't see a problem venting it to atmosphere, especially since it was just going to leak out anyway.

vent system, change hose/o-ring, replace dryer, vaccum system about 30-60 minutes, re-charge and its done

 

[Panama XJ]

XJ 95 A/C only holds 32oz. of 134R, try to charge it full and then check for leaks, changing O rings is very easy, the truth is that most A/C related fixes are very easy, thats is the reason the A/C people try to make Voodoo Shows and tell you that only they can fix the systems.