jhr

Hi,

I'm unable to find R12 gas anymore for the A/C of my 3rd gen RX7.

Do you know a solution to this problem ?

Is there a replacement gas which do not force to change the A/C system ?

Or is there a place where R12 can still be found ?

Thank you in advance for your answers.

SpinningDorito

iTrader: (2)

It depends on your location/local laws. Assuming the "Paris" in your profile is outside the US, I'm not sure how many people here can give you accurate advice on the legalities.

In the USA, the two technically correct solutions are to have the system leak checked and filled with R12 by someone with the certification and tools to safely do so, or retro fit to R-134a. Note if your system is not completely empty, you should have a shop pull out the remaining R12 before you open anything up.

To retrofit, you need to install the 134a quick connect fittings to your system (easy), and flush all of the mineral oil out of your existing lines (or as much as you can, not so easy sometimes). At that point you just charge it with R-134a and you're good to go.

There are some other approaches documented on this forum regarding some other alternative refrigerants you can use in the system that will work.

jhr

Thanks for your reply.

Is R12 still legit in the US ? because it is not in Europe.

Sorry for the newbie questions, but what is the quick connect fittings ? do you have a link to an image or to a place that sells it ?

When you mean flushing the mineral oil, is that oil mixed up with the R12 or is that oil running in another different line of the A/C ?

Finally do you if the R134a can be set up at the same pressure and/or quantity than the R12 ?

SpinningDorito

iTrader: (2)

R12 is regulated in the US, but not illegal.

These should be an example of the fittings. they should be pretty common online.


It is the oil mixed with the R12. R12 typically uses mineral oil, while 134a typically uses PAG oil. My understanding is that PAG and mineral oil do not get along. You might be able to find 134a + ester oil which would be safe, and should not react with the old stuff.

Still, it is better to just flush the system as best as possible.

Amounts required for 134a will be different than R12. The conversion rate and amount required should be documented online and in this forum. I bet it's in the service manual too.

I'd also replace your drier with a new one. If you are servicing your system because your freon level is low, please find and repair your leak before trying to recharge.

Since you don't seem very familiar with any of this, I'd strongly advise taking your car to an AC shop for this work.

jhr

Thanks, I will bring the car to a Mazda dealer, but as this time they have no clue on what gas to put in it

Thanks to you I know know that R134A will work and what needs to be done, I just ordered the R12<>R134A retrofitting connectors, I still need to find out the conversion rate/amount (if you have hint don't hesitate to share

Is there any known issue with replacing the R12 with R134A ? leaks issues because of thinner gas ? higher temperature of the cooled air ?

SpinningDorito

iTrader: (2)

Your Mazda dealer doesn't know? I am not surprised, but that is depressing. Here it is, straight from the 1994 service manual



You will get slightly reduced performance with a 134a retrofit, but in your climate it should not be noticeable at all. Maybe ~85% cooling capacity plus or minus. If the HVAC technician working on your car verifies the system has no leaks, you shouldn't get any just from switching to 134a.

However most people don't service their AC for no reason (you didn't really say what the issue is), so if you are taking it in for AC work I'm going to assume it stopped working because your freon is low/empty. In that case, they will need to find and repair any leaks.

My car (93) was mostly still original/stock when I bought it, but the AC did not work. About 80% of the o-rings had some sort of leak, they are rubber and do eventually fail with age. I went ahead and replaced them all. My high/low pressure switch was also leaking, and needed to be replaced.

It's not a horrible job to do on these cars, but if you are going to attempt it yourself, I would still ask a technician to make sure your system is completely empty.

From the sounds of it, you might be better off finding an independent HVAC technician instead of the Mazda dealership you talked to.

jhr

Thank you again for all these precious information.

In fact I stock my car and literally never use it, it has around 25K miles, and last time I used it I found out there was no more A/C. (I changed the gas 4-5 years ago).

I will of course ask them to check for leakage, they also have a vacuum system to remove existing gas/oil.

Are you running your 3rd gen on R134a ? If yes, beside the dryer and the o-rings, did you change anything else ? how many year are you running with it, did you already refill ?

Some other people are talking about R152a as replacement, did you consider it at some point ? (I personally prefer R134a which seems much easier to find out in France

SpinningDorito

iTrader: (2)

Yeah, first thing is to figure out why it stopped working. If you had to add a few years ago and its not working anymore, its probably a slow leak. They should be able to identify all of your leaks pretty easily and fix everything up.

I live in Texas, we're a little warmer than Europe, so I have opted to keep mine running R12. I wouldn't have any personal concerns using 134a in your climate.

152A is a good refrigerant and it will work in place of R12, but at least in the US is kind of a grey issue legally. It is approved to be used in new vehicles by OEMs, but not for retrofit applications. That doesn't stop a lot of people from doing it themselves though, as R152A is cheap and readily available (it is the compressed air/keyboard dusters that (at least in the US), you see everywhere)

Your regulations might be different. It is certainly something you could look into.

1994R2SSM

Simple Online test and $$ and anyone can buy R12 or its equivalent