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I have a question about the airconditioning unit: Does anyone know when they switched to R134 from R12? I have a 93 Beretta GT and I have read that cars prior to 93 used R12. But I have also read that it was used in cars up to and including 1993?! Thanks!

I'm thinking you still have an R12 system. From what I remember 1993 was the last year R12 was used by GM and 1994 started R134a.

Look for a fill valve, what type of valve/port do you see?

Do you have the v6? Check under the air cleaner on the canister.

In the example photo the red one he is holding is a R-134a retrofit kit adapter and the pipe below it has an R-12 fill port.
An R12 system can be converted to R134a. Usually you can put the fitting and fill it with R134a cans as long as it holds pressure.
R134a has a high and a low side, you want to put a low side adapter on the R12 low side port.
They are usually color coded Red for High side and Blue for Low side, however some cars I've seen black covers on all refrigerant ports. My 1990 Indy I had converted from R12 to R134a. All that was done was the retrofit R134a fitting was added and the system was evacuated and recharged with R134a. It blows just as cold as it did with R12.

Thanks! Will check it out. I hadn't used the AC up till now but summer here in Holland is unusually hot this year.

Judith wrote:I have a question about the airconditioning unit: Does anyone know when they switched to R134 from R12? I have a 93 Beretta GT and I have read that cars prior to 93 used R12. But I have also read that it was used in cars up to and including 1993?! Thanks!

I also have a '93 GT and mine is an R12 system, so I'm sure yours is as well.

I have mine charged with R12 still, probably one of the last on the planet.

As explained the retrofit is easy, although a shop would probably tell you that a bunch of parts need changed.

Yah the retrofit is super easy, just swap the fitting, then get a vacuum pump and then fill it back up. Assuming you don't have leaks.

Some shops will say it cannot be done and others will say you need a full 134 parts conversion and oil change and whatever, not necessary.

There should be a factory sticker which states what type of refrigerant you have
in the car.
But yes look for the type of fitting you have if the sticker is missing.
You can retrofit an r12 system with r134 but when I did mine,
I was instructed to add pag oil as well, because r134 will not mix with
the mineral oil used in r12 systems. The mineral oil will just lay in the low
areas of the system and won't cause harm.
I have two cars that still have the r12 in them. As people switched over to r134,
I was able to score a tank of R12 so I have it to top those cars off.
R134 in an r12 system works pretty good but not quite as good as r12.
You can't put as much r134 in as r12 because it expands more when hot
and could drive your high side pressure too high.
Google it and you can get all the facts.

There is an ester oil that is compatible with both refrigerants. I remember seeing 134a cans with ester in them.
I don't know how well it mixes with the mineral oil, but I read that its one way to do it.

ifixalot wrote:There should be a factory sticker which states what type of refrigerant you have
in the car.
But yes look for the type of fitting you have if the sticker is missing.
You can retrofit an r12 system with r134 but when I did mine,
I was instructed to add pag oil as well, because r134 will not mix with
the mineral oil used in r12 systems. The mineral oil will just lay in the low
areas of the system and won't cause harm.
I have two cars that still have the r12 in them. As people switched over to r134,
I was able to score a tank of R12 so I have it to top those cars off.
R134 in an r12 system works pretty good but not quite as good as r12.
You can't put as much r134 in as r12 because it expands more when hot
and could drive your high side pressure too high.
Google it and you can get all the facts.

Good point on the factory sticker, I didn't even think of that. Mine is on the passenger side strut tower.

On the 3.1 MPFI, the low side port is buried, it's towards the rear of the engine compartment near the steering rack.

EPfiffner wrote:

ifixalot wrote:There should be a factory sticker which states what type of refrigerant you have
in the car.
But yes look for the type of fitting you have if the sticker is missing.
You can retrofit an r12 system with r134 but when I did mine,
I was instructed to add pag oil as well, because r134 will not mix with
the mineral oil used in r12 systems. The mineral oil will just lay in the low
areas of the system and won't cause harm.
I have two cars that still have the r12 in them. As people switched over to r134,
I was able to score a tank of R12 so I have it to top those cars off.
R134 in an r12 system works pretty good but not quite as good as r12.
You can't put as much r134 in as r12 because it expands more when hot
and could drive your high side pressure too high.
Google it and you can get all the facts.

Good point on the factory sticker, I didn't even think of that. Mine is on the passenger side strut tower.

On the 3.1 MPFI, the low side port is buried, it's towards the rear of the engine compartment near the steering rack.

The v6 R12 Low side port is on the accumulator can on the driver side under the air cleaner.
I've never seen another port by the steering rack.

GT_Indy wrote:

EPfiffner wrote:

ifixalot wrote:There should be a factory sticker which states what type of refrigerant you have
in the car.
But yes look for the type of fitting you have if the sticker is missing.
You can retrofit an r12 system with r134 but when I did mine,
I was instructed to add pag oil as well, because r134 will not mix with
the mineral oil used in r12 systems. The mineral oil will just lay in the low
areas of the system and won't cause harm.
I have two cars that still have the r12 in them. As people switched over to r134,
I was able to score a tank of R12 so I have it to top those cars off.
R134 in an r12 system works pretty good but not quite as good as r12.
You can't put as much r134 in as r12 because it expands more when hot
and could drive your high side pressure too high.
Google it and you can get all the facts.

Good point on the factory sticker, I didn't even think of that. Mine is on the passenger side strut tower.

On the 3.1 MPFI, the low side port is buried, it's towards the rear of the engine compartment near the steering rack.

The v6 R12 Low side port is on the accumulator can on the driver side under the air cleaner.
I've never seen another port by the steering rack.

I checked out my '93 while I was doing the plug wires etc this weekend, and for some reason my low side port is way down by where the lines come out of the firewall.
My accumulator is buried down on the pass side under the front fender/bumper cover.
Who knows why, but I suppose the OP can find it in one of these places

EPfiffner wrote:

GT_Indy wrote:

EPfiffner wrote:

ifixalot wrote:There should be a factory sticker which states what type of refrigerant you have
in the car.
But yes look for the type of fitting you have if the sticker is missing.
You can retrofit an r12 system with r134 but when I did mine,
I was instructed to add pag oil as well, because r134 will not mix with
the mineral oil used in r12 systems. The mineral oil will just lay in the low
areas of the system and won't cause harm.
I have two cars that still have the r12 in them. As people switched over to r134,
I was able to score a tank of R12 so I have it to top those cars off.
R134 in an r12 system works pretty good but not quite as good as r12.
You can't put as much r134 in as r12 because it expands more when hot
and could drive your high side pressure too high.
Google it and you can get all the facts.

Good point on the factory sticker, I didn't even think of that. Mine is on the passenger side strut tower.

On the 3.1 MPFI, the low side port is buried, it's towards the rear of the engine compartment near the steering rack.

The v6 R12 Low side port is on the accumulator can on the driver side under the air cleaner.
I've never seen another port by the steering rack.

I checked out my '93 while I was doing the plug wires etc this weekend, and for some reason my low side port is way down by where the lines come out of the firewall.
My accumulator is buried down on the pass side under the front fender/bumper cover.
Who knows why, but I suppose the OP can find it in one of these places

That just seems like a odd place to put it. You have to jack the car up to get to it right? I wonder if they started changing the AC system in 93 in anticipation of the 134a mandate.
I know it wasn't to improve how cold it made the air, because that 88 GT we had with r12 would literally get so cold there was frost on the vents and it was somewhat snowing in the car on a 90+ degree Fahrenheit day. My 134a converted 90 Indy gets close as far as how cold the air is, but not enough to make snow like the r12 did. lol.

Yah the 87-90 v6's I've always seen the r12 fill on the canister by the trans front corner and the 94-96 v6's I always seen the low side in the front by the compressor and the high side on top front of the engine for the 134a.

This makes me miss r12. The 134a doesn't seem to be as good at cooling even with a larger r12 system (cnverted to 134a) like my old cadillac has.

Thanks for all the replies. It looks like the previous owner already did the swap. But I'll have the garage check it for me to make sure. I am not at all technical although I have been learning a lot since I've had this car.

Here are my two cents:

The system is likely STILL an R12 system, but the previous owner probably just installed the fitting adapters. There is more to an R12 or R134a system than just the refrigerant itself. Your car (being a 1993 model year) would have have an R12-specific compressor and thermal expansion valve, in addition to being filled with R12. If your car has been converted properly, it SHOULD also have an R134a specific compressor and TEV installed. An R12 system uses mineral oil for lubrication, whereas a 134a uses PAG oil, which are NOT interchangeable with one another. Most likely all the previous person did was evacuate the R12, install 134a fittings and refill, hopefully using the correct oil.

The biggest question I have is how well does your AC need to work? If you just need SOME cooling, a converted R12/R134a system is probably fine. If you want ICE cold AC, I'd recommend sticking with an R12 system. You can still get R12 equivalents such as RedTek R12a if you cannot find any cans of R12.

My 1993 GTZ is still an R12 system and works great. I installed a new R12-specific compressor and TEV along with new oil and a new drier before refilling in 2015. Still blows super cold today.

Yes r134a does not mix with mineral oil, that is why you need to use ester oil.
If there is any mineral oil left in the system the ester oil will mix with it and dilute it, the pag oil will not mix.
Easter oil works for both r12 and r134a.
PAG oil only works for r134a.
wiki link:
https://en.wikipedia.org/wiki/Polyolester

It is also recommended to replace the accumulator dryer canister and refill the new one with the proper amount of easter oil.
I usually get the one with the UV dye so if my systems ever leak out I can find the leaks easily.