LarryD

Ok, so after working my way through the troubleshooting, the AC is running again (bad AC Compressor Relay replaced) but it is only cool and nowhere near icy like it used to be. The compressor cycles on and off about 5 second intervals so guessing now that it is low on R12. After a lot of searching I came up empty handed on finding someone to check for a leak and recharge it with R12. So, does anybody have a procedure for the conversion specifically for the 90 to 92 Camaro..????.. What I would like to do is complete as much as I can myself then take it to a shop for finish up vac and charging. I understand at this point the only part that needs to be changed is the accumulator to one that has R134a compatible dessicant. Is there someplace to buy an aftermark accumulator (and/or other parts that need to be changed) for the 92 Camaro that is compatible with R134a or would one from 93 work with the 92???

91 355 z28

STOPPPPPPPPP!!!!!! converting will be the biggest mistake of your life.. i have r134a in my 91.. it sucks *****.. if its not cycling properly first check your pressure switch.. that is more likely to have gone bad then r12 leaking.. unless theres ever been any damage to the system, guys have systems that are 30 years old and never been touched.. ive had to recharge my r134a once a year.. the system holds vacuum but do to the smaller molecule size of r134a it just leaks out of every fitting.. my advice is search for someone whos got some r12.. trust me if u look theres a ton of it still out there.. i go to technical school for cars and pretty much every teacher has got it

LarryD

Is that the switch on the Accumulator?? Also, anybody have experience with Freeze 12??

92Forumla

iTrader: (2)

Ya I have used Freeze 12 and it works really well. If I am not mistaken, there is like butane or propane or something like that in there so a lot of people stay away from it. I had no problem with it at all.

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Edit: The switch on the side of the Accumulator is your Clutch Cycle Switch, that is the one you want.

rideon1200

Its not just accumlator. The gaskets in the compressor willl also dry out. Call your small HVAC companys and find one that is familiar with hot shot. It is a drop in replacement for r12. You use 80% of the r22 vol. Works great.

MikeH

iTrader: (10)

I bought one of the 20.00 30.00 kits from the local store. I had a leaking compressor, all i did was replace the r22 with the 134a. Its been working great for over a year.

JamesC

iTrader: (5)

Many members have had fine results with the conversion--I'm not one of them. After repeated efforts from a shop I respect, the system simply wouldn't cool sufficiently. I eventually swapped back to R12, which blows darned cold

JamesC

Abird4u2nv1

iTrader: (-1)

Swapping to R134 is not bad, granted it does not blow as cold as 12, but its as easy deal. Swap the fittings use appropriate oil, put under vacuum for a while and charge. If its not cooling good, you have a problem, maybe a compressor or a clogged orifice. Really you need a good set of gauges to be able to see what exactly the system is dojng. I'm a mechanic and certified in A/C, and I have no problems on a daily basis getting cars to blow 47 degrees or lower out the vents with 134. Factory acceptable temperature is 47 degrees. R12 is just too expensive to play with. Around here your talking 55$ a can, compared to 134 being about 10$ a can. And I'm one of those who DOES NOT believe in any of these supposed freon substitutes. There junk. I've seen some cars smell of propane with that crap, but to each his own.
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2 more cents to add also. Our camaros and firebirds also aren't the most effective A/c systems out there. To run properly and cold, you need to be able to keep the condenser cool, something that just doesn't see a lot of air from our cars.

LarryD

I changed the pressure switch on the accumulator and it still does the same thing. Is there another pressure switch in the system somewhere??? As to R12, there are no longer any shops in the area that handle it so I am out of luck there.. I might start with Freeze 12 first and then move to R134a if that doesn't work as it sounds like I might get lucky with it..

goomaan

iTrader: (2)

Ok now I am really confused...

My question is did some of the 90-92 Camaros already come with R134a?

I had a 1990 RS 3.1 that I purchased new (in nYC) and it was already a R134a AC system.

Tomorrow I am getting a 1991 Z28 (5.0) and the air needs to be charged. I was hoping to find out if it was R12 or R134a... Is there any way I could tell just by looking at it?

LarryD

My manual on the 92 says R12 and right on the side of the compressor is a sticker that says it is R12. I am not sure if they were mixed between 90-92 but look for a sticker. Maybe somebody had already retrofitted your 90 to R134a..... Oh, if it is R134a the fittings for charging it are different from R134a (larger I believe)..

From what I have found, there are three choices for freon charge related problems:

1) Find somebody to fix the R12 system - I haven't had any luck with that yet.
2) Simply charge it with Freeze 12 (evacuate maybe) - Some say it works good, others say not so good.
3) Convert to R134a - Again, some say it works good, others say not so good.

R134a conversions are described as several different major levels.

1) Simply evacuate the system and fill with R134a.
2) Replace the accumulator (receiver-dryer), evacuate the system and fill with R134a.
3) Replace the accumulator, replace the o-ring seals, evacuate the system and fill with R134a.
4) Replace the accumulator, replace the o-ring seals, replace the orifice tube with a "blue Ford" one, evacuate the system and fill with R134a.

Additionally, people recommend checking for leaks, flushing the system, and maybe replacing hoses, evaporator (in passenger cabin), and/or condenser (near radiator) if leaks are found.

pizza_guy

I hate how everyone claims "134 doesn't blow as cold as (insert "R12" or latest gimmik here)" I run R134, and you can't even tell the systems not stock from the vent temps. But then again, I completely redid my A/C system to work with the R134. Novel concept, huh.

If ya put a horse saddle on an elephant, do ya think it'll fit without modifying it??
Hmm...lets try this again.
If you put a bullet from a .22 into a gun designed for .45 ammo, your going to lose performance.
Wait...wrong forum for that one.
If I put straight ETHANOL into my engine designed for GASOLINE, of course it's not going to run properly. Surly that makes sense to people here.

I'm not a chemist by any means, but it's obvious(to me anyway) R134 is quite a bit different than R12. If you redesign the system properly, it will work just as well as R12. Heck, people properly redesign their powertrains all the time, and spend quite a bit of money doing it. Then they want to put in $20 "A/C in a can" and expect it to run perfect. Come on.

And then they don't wan't to flush out the oils from the R12. Guess what...THEY AREN'T COMPATIBLE. You must completely clean out your system before installing R134. Period. Unless you like replacing your soon-to-be-ruined compressor. Ever heard of "black-death" in relation to A/C compressors?

Besides the new o-rings and accumulator, you MUST change the orifice tube as well as adjusting the low side pressure switch to the PROPER PSI FOR 134. I'll bet my driveshaft that most of the "it's not as cold" claims come from improperly adjusted low-side switch. Those few things alone probably won't get you to R12 efficency, but it'll be better than "A/C in a can". Adding the PROPER condensor will pretty much get you there. You'll need new lines for that though, cause "My R12 lines won't fit my R134 condenser" After that, the compressor is about all thats left. If the switches are adjusted properly, the compressor should be fine for R134, AS LONG AS THE OLD OIL IS OUT.

Guess what, it's not easy to make cars work properly. And when its not, we get, "Stupid R134 doesn't work in my R12 system!" Imagine that.
..."Stupid" ethanol won't work in my gasoline engine either.

LarryD

I agree.... I think (in general) that the poorer performance probably came from the quick fix approach... That is, the more you do to get to R134a designed components the better the efficiency in cooling when using R134a...

Reid Fleming

iTrader: (2)

I thought you guys might like to hear about my experiences. I was in the same boat as LarryD. Original R12 system that hadn't been touched. Was cycling on and off. Low freon.

The original system was 2.25 lbs of R12. I took it to a shop and had them evacuate the old stuff. They pulled out 1 lb and 15 oz. Let's call it 1.9 lbs. I was surprised there was that much stuff still in there. Had them run a vacuum on it for half an hour.

I put in 3 cans of Autofrost (R406a). You need to use 80% of the original R12 amount and the stuff comes in 9.6 oz cans. So exactly 3 cans was what I needed. There is a special procedure you need to do to put the stuff in. Nothing major. Basically you put in 2 cans and let it circulate and then add the 3rd. A major benefit of Autofrost is that it uses the same oil as R12 (mineral oil).

After I'd put in 2 cans and was waiting for it to move around through the system (car idling), I checked the low side pressure with my A/C gauge. It was cycling off at 26 psi and cycling on at 47 psi. Adding in the 3rd can made it hang around the 30 psi range and cycling went down to a minimum.

I decided to take it for a drive afterwards and see how cold it was. Putting a temperature probe in the center vent and cranking on the A/C, it immediately went down to 40° and then started creeping down lower. How cold did it get down to?

31°F

Proper evacuation and vacuum are essential. The right amount of refrigerant being installed is important too. I used the multiple page Autofrost booklet instructions rather than just reading the can. (GM cars with CCOT systems like ours should let it circulate for longer before adding the 3rd can. I used 6 minutes instead of 3 minutes. I also only used the low side for install)

Last night I went for a ride in a Lincoln. Properly functioning R134a system in it. Tried to see how cold it would go. 45°F being the answer. It didn't seem like it had warm air conditioning. It felt fine actually. But I think the thing with people describing if it's cold or not depends more on perception than real vent temperatures. Lots of people say R134a is cold after converting. But without actually measuring the duct temperatures, you're just guessing.

If you have an R12 system that isn't up to snuff anymore and you want COLD air conditioning. Use R406a. If you live in the southern humid hot areas, this stuff is a must. 30'ish duct temperatures will dehumidify nicely. Upper 40's won't.

LarryD

Hey, thanks for the info... I hadn't run across AutoFrost R406a anywhere in my info search and haven't seen it on any shelves but will do a google search on it... I know my system does have some pressure since it sprayed a bit changing the Low Pressure Switch out (shotgun approach) so it has similar symptoms to yours... My clutch relay was dead so had to replace that first. It probably died because it was cycling so much before I realized there was a problem...

Heading to google to check out the R406a.... Doesn't hurt to look at all the options and do the cost benefit trade...

rushtk

Do you have to put r12 in or can you have it empty and do the r406a after evac? Thanks.

LarryD

Don't mix R12 and R406a. R406a is blended to perform the way it is. If you are low on R12, I would suggest that you buy some R12 off EBay and recharge (just add more) with that. If your system has some R12 and you want to go to R406a, then you need to recover the R12, evac and then fill with just R406a. If the system is empty, then evac and then use all R12 or all R406a which ever you prefer. Again, don't mix the two.

Hope this answers your question...

DynoDave43

iTrader: (11)

I've used this product with good success. A drop in, fully compatible replacement for R-12.

http://bennettsupply.net/HC-12a.htm

phasevariance

I converted to R134A only because my system was busted and needed a new accumulator due to a cracked line. Maybe I'll give R406a a try when it's time for a new compressor.

Definitely not gonna pay the blackmail prices for original R12.