97 xlt aircon repair

[IMINYOURCHAIR]

Okay. I bought this expy back in november and it was missing the compressor and the manifold hoses. I have since then acquired the hoses and compressor. I plan to replace the drier when I get ready to actually charge the system. I have not yet verified that the system succumbed to the "black death" as it is called. the inside of the hose i could see looked okay but I haven't pulled anything apart that remains in my system. I plan to flush it over the weekend to see how things look then go from there. Here is the part mine was missing along with the compressor AC is a new area for me but I do know it has to hold at most a 30hg vac to get the moisture out. but I don't want to put the compressor in then charge only to realize the evap or condenser is clogged with trash from the failed ac comp. i believe the ac ran out of freon and the PO was fooled into having the system removed by a horrible shade tree mech.

 

[hooraah]

Hey,

I just did some recent AC work and posted my experience here:

http://www.expeditionforum.com/f42/some-c-work-r134a-filling-23057/

You might be able to use that as a guide to recharging your system but I'd suggest supplementing it with something that takes each step into more detail.

Looks like you were missing the same hose I had to replace.

I only replaced the one hose, so I didn't have to do much with the oiling. If you replace the compressor and a line, and you flush the system, you're going to have to add the correct amount of oil back in, of which there are different ways of calculating how much is the 'right' amount.

If you suspect problems with the system, and you're investing in a new compressor, I'd probably take the time to replace the orifice tube and inspect it for debris. If you have an Exp with rear AC, I believe there are two but someone can correct me on that.

Once you get it all put back together, you'll need a real set of gauges and a vacuum pump. Vac it down, check to see if it holds, then refill. Dont forget to purge the line after each can.

You can buy a set of 12 cans on amazon for $53, which I would recommend since the cans are $10/each at walmart.

If you have rear AC you will need at least 5 cans.

 

[IMINYOURCHAIR]

thanks for the info. I decided to wait on flushing but I will pull the orifice tubes and inspect for debris before I buy anything. I will look into the service manual tonight and see if it mentions anything about a second tube. This is the second time I have heard it mentioned so there is likely one back there somewhere.

 

[IMINYOURCHAIR]

that guide will help me. Now I just need to source a vac pump and gauges.

 

[vigman]

Just a note... a "PROPERLY" restored AC system will need to be HOSPITAL CLEAN on the inside lines.. The metering valve is ITTY BITTY and has a fine mesh screen on the incoming side....It might take 2 or more cleanings including changing the drier ( which is akin to an oil filter ) to get it good....If the system has been exposed to atmosphere for a LONG TIME.. those tend to be the hard ones to get " perfect "... For those systems I use a junk yard compressor ( read good used ) so I can cycle gas/liquid under pressure and let the system self clean AND Self dry.. A vac pump is a GREAT starting point, but running for 2 hours is better...to get all the MIRCO SLUDGE out.. which will eat your compressor and plug your expansion valve...the bottom line is if you can get better than 17 degrees exchange from cabin air inlet to vent duct... Your doing great!

Mike

 

[IMINYOURCHAIR]

Okay. From your post. It sounds like you use a used compressor to clean the system then replace the drier and compressor again. After running something through it.. would you care to walk me through it assuming mine has had atmosphere in it for awhile

 

[vigman]

Take a look here E bay item # 300640179892
the little valve ( brown ) is the inline metering valve… it hides in a pipe….
you typically need a Expansion Valve Tube Remover to pull it….
Expansion Valve Tube Remover | AutoZone.com
" Expy with dual air the orifice is located just inside a fitting in the liquid pipe that runs just under the battery. The fitting is visible just past the battery, firewall side and at the battery box."

I would clean the old one FIRST using this…
A/C Pro / 1 qt. flush and clean (CQS-11) | A/C System Cleaner | AutoZone.com
Do not use carb cleaner or WD-40 you don't want additional contaminants in the system….
Break as much of the system up as you can & use a AC rated FLUSH… all new O rings on refit and wipe AC oil on the O rings while replacing.

I would remove the condenser to flush that.. PLUS remove all bugs N junk at the same time.. you can LIGHTLY pressure wash the exterior as long as the internal ports are sealed ( e.g. rubber cork )

Last mount the compressor, hook up s gauge set, hook up a 2 stage van pump, open both high and low pressure sides on the gauges and pull a van for 1/2 an hr ( for starters ) …
You need to get the system AS LOW AS IT CAN GO..28-30hg ( inches of mercury ) … for the 1/2 hr this is the initial " boil off " of any water in the system AND the system sealing test.

Now WHY does everything need to be SOOOO CLEAN ?
Well it's easy, you are exchanging liquid to a gas back to a liquid and pumping that stuff round & round in a closed loop..
The expansion valve is SIMILAR to the tip of your spray can… When it's new, it puts down a nice even coat of paint, not so much the next time when you forgot to clean the valve.. it's all blobby & spluttery if it even flows at all !

And any WATER in your system.. is a SLOW death. Freon under pressure, with H2O makes a MILD hydrochloric ACID which LOVES to eat things..Nuff said there.

Any grit in your system chews on the compressor valves, seals, pistons etc etc… You wouldn't run your dirt bike desert racing W/O a GREAT air filter.. otherwise BUH BYE RINGS & BORE.

AND AC is not about the cool breeze hitting your face as your driving , that's a BY PRODUCT of the system… them MAIN JOB is to pull heat out of the cabin via the freon and dump the heat out the condenser.. which gets the freon " cold " enough to pull more heat out of the cabin. Round & round she goes …..

I was SKOOLED, cleaner, cooler , longer….


I'll stop here for questions…
Mike

 

[vigman]

Additional:
From a post in another forum…
"The location was just as you described. It just took a little investigating slightly under and forward of batterybox towards firewall. Thank you again. The old orifice tube was somewhat clogged with fine metal particles- could be compressor going bad, huh? So far it's blowing fairly cold air."
Reply
"Yes, it would appear the compressor is starting to shell out. Better to get it replaced and filter flushed before it gets real bad. Replace the accumulator and orifice as well."

So if you see that.. you know why the system went BOOM!

 

[IMINYOURCHAIR]

Update: Today I pulled the expansion valve. it looked....eh..good enough to actually go ahead with installing the used compressor. the oil looked okay but I have no clue what's left in the system (if any) I can't do anything yet as I know no one with the tools I need to vacuum the system and charge it and I need to replace the radiator and cooling fan clutch this weekend.

 

[IMINYOURCHAIR]

alright, I got it charged and cooling properly. Thursday eve I installed the compressor and manifold hoses. Friday I had to remove the compressor slightly to tighten the manifold bolt as I forgot to do that first and learned the hard way. Last night I rented a vac pump and gauges, I tested the pump and it could only pull about a 25 hg vacuum but I suspect the gauge wasn't calibrated to the dial. on the first attempt to vac the system I couldn't seem to pull a vacuum so I began to look for leaks in an odd way... I had to blow into the hose as I had no other way to put air in other than that. I sprayed a few connections that I did touch and nothing showed, But, I found one leaking that I had not touched. the lower lone on the condenser was missing a seal... I don't know how but it was. I didn't have a seal and wanted this under vacuum overnight and luckily my aunt has a broken down car with ac so I used an o ring from there to get a seal and thankfully it worked.

today, I checked the vacuum and it had not lost any which was very relieving! I added about 5 or 6 oz of pag150 oil and added the first 12 oz can into the system. the compressor didn't want to kick in with low pressure at about 65 or 70 on the low side. I had to re seat the connection on the drier then it engaged and drew the rest of the can into the system and began short cycling. it took the other two cans rather slowly but managed to empty them both.

at that point the compressor was staying on until i revved it to above idle then it would cycle on/off. I added another 12 oz can for a total of four cans and it still cycled but under higher revs (1500 to 2500 and pressure was dropping to about the 30 psi range) and was blowing at about 58f at that point. ended up finding a 10 oz can for cheap and added that to bring the pressure up more then the cycling stopped and the pressure held steady under throttle...

right now the temp from the vent is about 48 on normal ac and 45 on max ac and the compressor isn't cycling when I'm cruising like it was with four cans.

for now I will leave things as they are and see where it goes. wouldn't be a bad idea to have a new drier/orifice tube and oem compressor but what works works. also, it feels nice to be capable of doing this work on my own and only be 21 years old

 

[stamp11127]

If your interested in more information on mobile a/c systems check out MACS - mobile air conditioning society. They have a study guide on the 609 Cert that covers r134a do's and don'ts. You need to watch how much oil is added to a system. If yours hasn't been flushed or had oil removed there is a possibility that you have too much in there.

 

[vigman]

I hope you cleaned that valve before you put it back together.. there was a fair amount of YUCK on it....

 

[vigman]

And used O ring...not my FIRST choice.. was the donor car a R 134 system?

 

[IMINYOURCHAIR]

If your interested in more information on mobile a/c systems check out MACS - mobile air conditioning society. They have a study guide on the 609 Cert that covers r134a do's and don'ts. You need to watch how much oil is added to a system. If yours hasn't been flushed or had oil removed there is a possibility that you have too much in there.

i believe for the most part it was empty and I lost a lot of oil in the compressor and manifold hose in transit from GA when I got cut off and it all tumbled and spilled. I checked that the hoses and compressor were empty before I installed it but if it lasts the summer I may have it flushed and replace the compressor and drier with oem parts as the used compressor had 320k on it when I pulled it from the donor. that will help me be sure I have the exact amount of oil in there. if everything works for the summer I will just run it till it shows signs of failure.

""I hope you cleaned that valve before you put it back together.. there was a fair amount of YUCK on it.... ""

yeah, i let it sit in gas for a bit and took an old tooth brush to it then hit it with compressed air. I dipped it in some of the ac oil before installing it.


""And used O ring...not my FIRST choice.. was the donor car a R 134 system? ""

well, I didn't trust the o rings auto zone was selling and the donor was a near perfect match and it was what I had, it came from an 05 kia so it wasn't too old. the rest of the seals were in great condition and not hard at all, i could see no signs of age on them. any connection I opened got some oil on the seal before being re connected and I believe that helped a great deal.

 

[IMINYOURCHAIR]

alright, it's been five days since the recharge. the system seems to be working fine and is cooling great except when I am at idle and at nominal engine temp.. It feels like the temperature from the vents goes up about 8 deg until I rev the engine to about 1.3k (idle at about 6 or 700 according to tach) when I hold the throttle there it goes back to cooling after the clutch fan spins up again.

the only complaint I have is that the ac is on in every other selection other than "panel" I am going to try to get a push button switch to override the compressor activation as I used to be able to do in my last car.