Attention: AC Guru's! Need help with my AC!

[8UWITH6]

Hi guys. Just so you have an idea of what Im trying to do, Ill start from the beginning. Last may when I bought my Ttype, the AC did NOT work, but did hold a vacuum when put on the machine. So I converted it to 134A at my work (Jiffy Spooge) and it worked decent for about 3 months, then I had to add some freon from those little cans you can buy to keep it running. So obviously there is a small leak.

Fast forward to today......I evacuated the 134a in the system, (or what was left of it), and it seemed to again hold a vacuum for an extended period of time. Heres what I have done so far.....After evactuating it, I pulled off the accumulator and replaced it with a Napa replacement (they had a huge sale today). I also replaced the oriface tube and all the o-rings on the accumulator and OT fittings. I ran out of time in the Tech Center to try and charge it.

Heres what I need to know.........

1. I know I have to add oil to the system......or that I was suppost to put some oil in the accumulator. Do I have to take the accumulator back off to add oil to it? Or can I just add it through the service port or add it while Im charging the system?

2. The old oriface tube was dirty, but not clogged, and I didnt *see* any metal shavings, but what are your thoughts on the compressor going out?

3. In class, Ill either be able to use the charging machine to add 134a, or Ill have to use those stupid cans from the store. Either way, Ill have a gauge set to look at and compare pressure readings. If I use the stupid cans, I put them in on the low side correct? Do I hold the can upside down? Pllease give me your thoughts on this.

4. What pressures do you guys like to see? I know the gauge set should read ambient if the system is properly charged. But what about running? High side is what, 150psi to 300psi? Low side is 30-60psi? I cant remember.

Oh yeah, I plan on injecting dye into the system so I can pinpoint the leaks, if any. (Fingers crossed). Id just like to know if Im heading in the right direction. THANK YOU!!!!!!!!!!!!!!!

 

[NICKG]

here is your problem

r134a has a very small molecule, r12(what the system was designed for) has a much larger molecule. what happens is that the 134a permeates the hose(yes it passes thru the hose itself) r134a syestems in all modern cars use a barrier type hse that has an inner liner in it to prevent this. your soulution is to go find a couple cans of r12 and use that. try ebay, i got a bunch of 1lb bombs for 25 each or less. r134 is not nearly as cold as r12 anyway, i get 34 deg air out of my vents (last week in 95 deg heat )
you would be lucky to get 45 out of a converted system. good luck nick

 

[1ARUNEM]

Neal,

I am by no means an ac expert but will try to answer some of your questions from my experience..

You can add oil thru the charging system. You can get a can of it and add thru the service port.

As far as the compressor, as long as it is quiet and the clutch mechanism is functioning properly, i'd leave it alone. I have had too many "replacment" compressor that crapped out when i should have left well enough alone.

Shouldn't be any problem to add cans of freon and yes, holding the can upside down and shaking them a bit should work fine.

Your gauge readings sound about right if memory serves. Every gauge i used indicated "ok" ranges to go by. Sorry for being vague, it's been about 5 yrs since i've charged a system..

HTH..

P.S. See if you have access to a "sniffer" to detect the leak. They are pretty effective..

 

[Ellis]

1. If you use the cans from a discount chain, you can get them with oil pre-mixed in.

3. On the few systems I've done, I added the 1st can upside down, and the rest rightside up until full.

4. I have always added enough to bring the system up to the specified capacuty (in oz. refrigerant) from being evacuated. I've only had one leak, and I just ran in more until I got low side between 30-40psi.

There is a new product available that is an anerobic stop leak. It is dormant in the system, but when it encounters a leak, it "clots" like blood. I've only seen it used once to seal a condenser core in a '99 Caravan. The shop manual calls for some ungodly time frame to R&R the thing, so my dad's mechanic used it. Worked great, and he can't stop raving about it. Email me if you want the brand name, I can try to find it.

On a side note, I've been told by more than one person that R12 is less "efficient" than R-134a, but have not gotten a satisfactory answer as to how that is.

The 1st vehicle I converted was an Acura, and the air outta the vents was 38°F. Stayed that way for 2 years. The air in the truck I have now only gets down to about 52-53°F (on a 90+ °F sunny day in FL), but then again it's a mid 80s Jimmy w/ a lot of glass and an undersized system to start with, not to mention the slowly failing compressor.

My experience with non-barrier hoses has been positive. Apparenty, newer hoses will not work well with the smaller R134a molecule, but oil-soaked and aged hoses aren't as susceptable to leaks.
hth

 

[AsphaltAnihil8r]

Re: Re: Attention: AC Guru's! Need help with my AC!

Originally posted by Ellis
1. If you use the cans from a discount chain, you can get them with oil pre-mixed in.

3. On the few systems I've done, I added the 1st can upside down, and the rest rightside up until full.

4. I have always added enough to bring the system up to the specified capacuty (in oz. refrigerant) from being evacuated. I've only had one leak, and I just ran in more until I got low side between 30-40psi.

There is a new product available that is an anerobic stop leak. It is dormant in the system, but when it encounters a leak, it "clots" like blood. I've only seen it used once to seal a condenser core in a '99 Caravan. The shop manual calls for some ungodly time frame to R&R the thing, so my dad's mechanic used it. Worked great, and he can't stop raving about it. Email me if you want the brand name, I can try to find it.

On a side note, I've been told by more than one person that R12 is less "efficient" than R-134a, but have not gotten a satisfactory answer as to how that is.

The 1st vehicle I converted was an Acura, and the air outta the vents was 38°F. Stayed that way for 2 years. The air in the truck I have now only gets down to about 52-53°F (on a 90+ °F sunny day in FL), but then again it's a mid 80s Jimmy w/ a lot of glass and an undersized system to start with, not to mention the slowly failing compressor.

My experience with non-barrier hoses has been positive. Apparenty, newer hoses will not work well with the smaller R134a molecule, but oil-soaked and aged hoses aren't as susceptable to leaks.
hth

Never ,,Never assume that since it holds a Vacuum that there is no leak ..I had a Low temp walk-in freezer hold a vacuum for 3days ( this is when I was a rookie),Charged it up ra great ,the next day there was no R12--Always pressurize the system to check for leaks

 

[8UWITH6]

Thanks for the replys, still looking for a more opinions on the accumulator and the dirty oriface tube. I figured Id at least replace these 2 items, shoot up the system with dye, and see where I have leaks........any other ideas?

 

[NC87GN]

check those lines carefully..

8uwitha6,
I am by know means a guru but I think I can help you to pinpoint your leak. Locate the juction where the aluminum lines run into1 the rubber hose starting from your compressor. I took a leak meter (GM dealer had one) and detected a small leak at that junction. I bought new GM lines then converted over to 134A. Blows cold and holds pressure well. Check those lines carefully as many people bend them too much when installing the K&N filter. HTH


Mike Banas
87GN

 

[salvageV6]

My lines leaked right at the junction where they sit on top of the K+N filter at the end of the MAF.

Metal to rubber joint near the radiator.

 

[8UWITH6]

OKay guys, well I took the old Oriface Tube to my AC instructor........we both agreed that the rubber lines are probably being eaten away from the inside out. There was actually rubber bits in the OT. There was maybe 3 specs of aluminum. So....what do you think? Replace lines AND compressor? Where should I get the lines........and/or compressor? Id really like to get this working soon........so please reply if you know about AC. Thank you

 

[Red Regal T]

I guess it depends how much money you want to spend. I had to replace my original compressor with over 200,000 miles on it and priced a rebuilt for $99 with lifetime warranty. That's pretty cheap. Auto Zone had them for $169 w/ warranty. I bought a GN drive train that came with a compressor so I used that. Put on new accumulator and orifice tube. Didn't have equipment to evacuate so added less than 2 1/2 cans of 134a and I'm good to go. I've been using 134 for the past 2 years. I see no problem with it, but there is a big plus. That is, you can go buy it anywhere for $5 or $6 a can. Even if you have a small leak you can afford to add from time to time. You might think about replacing your hoses, also

 

[GNX423]

i got new hoses about 2 years ago from carparts.com, they were only like $60 and fit well, i cant see them being that much more anywhere else.
Good luck
Mike

 

[GNX423]

heh i just went to gm parts direct and the hose assembly is:

GM Part # 25525272 HOSE ASM
$54.31



not bad , imo
mabe someone can say whether this is the correct part # to verify.

Mike

 

[Benched]

How do you pressurize a system to check for leaks?

 

[8UWITH6]

Mike, thanks for the heads up on the AC lines, Ill probably do that!

Benched, actually what you do is pull a VACUUM on the system with an AC Evacuation Machine. Usually you pull it down to about 30 inches of vacuum and see if you lose vacuum over a 20-30 minute period. Only problem with this is, the system is used to being pressurized, not in a vacuum. Sometimes you get false leaks because seals are so used to being "pushed" (as in pressurized), not "sucked" (vacuum). At least thats what Ive learned. HTH.

PS- plan as of now is to replace lines and charge the thing up by using a Oil Recharge Kit, 2 1/2 cans of R134A, and a shot of dye to check for leaks. Im gonna see if the compressor stays alive, because Ive heard all the horror stories about reman compressors. When it worked last summer, it was relatively quiet, but who knows. I plan on charging the system through the accumulator (low side) while jumping the high/low switch circuit on the accumulator to get the compressor to cylce during charging. Any other comments or ideas? Thanks guys!

 

[dhause]

Hey Neil,

Most shops I've talked to say it's worth the bucks to recharge the system with R12. Much colder, and that has been my own experience. I recharged that black Ttype I had and it just didn't get cold, after almost 3 cans and oil. Coulda been leakin' like a sieve, because I did it in my garage and didn't have the tools to check. Plus, the system was designed for R12, and I think it will last longer, be colder, and not be as hard on your original parts. Just my 2 cents, I'm no expert.

Say, can you do an AC evac and leak check at Turbo6Lube where you work now? I'm prolly going to get my personal GN recharged, but will splurge on R12 instead. Let me know.

PS, using that bra much?

 

[Red Regal T]

Why are you guys alway pushing R 12. Post above claims he paid $25 a can, like it was a bargain . No problem with $6 a can 134a that you can get anywhere.......DOES THE JOB. Get over it!

 

[dhause]

John, my experience with 134A goes like this: Bought a new 94 Trans Am with it, and the car was NEVER cold. Had the dealer recharge it when it was practically new, and still never got cold. That pissed me off, esp with a car with as much glass as that one had. Most systems I've been around with good R12 get ICE cold, to where I can never stand to leave it all the way down.

Maybe they've made progress on the stuff, because newer cars do seem to be colder than mine ever was.

Also, R134A does leak more if you don't replace everything, and I personally would just rather use 12 and all of my original components as long as I can, without adding a can every 3-6 months. Maybe it's just a preference. I'm sure both do the job, but I don't think 134 gets cold enough.

 

[8UWITH6]

Doug,

I can evacuate and recharge the system at Jiffy Spooge. I can also suck it down into a vacuum and check for leaks. Beware, R12 is VERY expensive at Jiffy Lube, IF we even have it anymore??? I cant remember, so Ill have to check on it for you. Ill let you know. Probably see you around town sometime soon. Im out of school in 2 weeks.

As for using 134a, Id rather replace all the parts of the AC system at cost (working at Superior Chevy as an intern this summer ), and use 134a, then charge with R12 (expensive) and lose it due to a small leak. Im replacing a few parts in the Ttype, shooting it up with dye, so I can see where it is TRULY leaking. Im gonna keep the original compressor as long as possible because Ive only heard bad things about remans. I just hope the condenser isnt leaking.......or evaporator, but MOST leaks are on the high side of the system anyway. So we will see what happens. Thanks for the help guys.

PS-havent even put that bra on a car yet Doug, lol. I was gonna test fit it on my ttype......but, uhhh, theres no hole in it for the hood ornament! LMAO.....where did I put those scissors????

 

[OneQuikV6]

Originally posted by dhause
Hey Neil,

Most shops I've talked to say it's worth the bucks to recharge the system with R12. Much colder, and that has been my own experience. I recharged that black Ttype I had and it just didn't get cold, after almost 3 cans and oil. Coulda been leakin' like a sieve, because I did it in my garage and didn't have the tools to check. Plus, the system was designed for R12, and I think it will last longer, be colder, and not be as hard on your original parts. Just my 2 cents, I'm no expert.

Say, can you do an AC evac and leak check at Turbo6Lube where you work now? I'm prolly going to get my personal GN recharged, but will splurge on R12 instead. Let me know.

PS, using that bra much?

FYI, Doug, I am in the process of doing the AC on that car now. Needed a compressor, and the lines were cracked where they attach to the drier. Mucho shavings in the oriface tube as well. We had charged it right after I bought it, and it worked for about 2 hours Clutch stopped working even though it had pressure...so we decided to tear it apart. Compressor was bad afterall. Should have it done tomorrow as we're still waiting on lines. Wish we could use R12, but my friend's shop stopped buying it.