newbie A/C question
 

My A/C is not blowing cold at all and I am sure all I have to do is recharge/fill the a/c. can anyone explain this procedure to me. thanks

well, first, you gotta determine if it's R12 or R134a. The fittings are different, and you will not easily be able to find R12. Not to mention it costs an arm and a leg.

Second, you should put some A/C gauges on it to see if there's any refrigerant left, and if your compressor is working or not.

But, if you just want to vacuum it down, and refill it, you either need an A/C shop to do it, or a vacuum pump, hoses, fittings, etc. Then just vacuum it down to remove all freon, moisture, contaminats, etc. Then fill it with the appropriate amount.

Who fills or takes care of the AC in your other cars ?

Where are the charge valves located?
 

I have the same issue. Can anyone tell us where the low pressure charge valve is located? Regardless of R12 or R13a the location must be the same right? Attached is the diagram but I do not see where the valve location is??

Busted 7 answered my question. I guess it takes a little longer for the thread to post tonight. I thought it did not take.

Guys, this is not a job for amateurs. fd3annen it's highly likely you have a serious leak in your system, or a compressor malfunction. Even if you don't, just recharging the system with a shot of refrigerant is not the way to go. You want to evacuate the system first to get all the air and moisture out otherwise your system won't be cooling at full capacity. For this you need the right equipment and expertise. Be smart and take it to a professional.

Agreed, charging the A/C is not a shadetree mechanic type job. It's not worth it, especially if you have R12 (expensive!).

thanks
 

I appreciate all the help.... I will definetly take it in and have it looked at by a professional. Should I find a rotary specialist, a mazda delearship, or just a reputable mechanic. thanks again for the help.

Any A/C specialist will do. There's nothing special about the system in the F/D that anyone who works on air conditioning won't be able to handle it. This is a case in which the Mazda dealership isn't necessarily a bad idea. But your city also will have shops that deal primarily in auto A/C.

Whoever looks at the system may suggest doing a leak test if they think that's the problem. It's possible you may have a hose that will need to be replaced. That and an evacuation / recharge will probably do it. If it's something more serious....the compressor...evaporator...or condenser you may want to shop around for the repair and price compare. It wouldn't be surprising to find a significant difference in price among the various shops for the same repair.

Ask them to diagnosis the problem first and give you an estimate before they proceed with the repair, if one is needed. If a recharge is all that's required they should have that price posted, or they should tell you it up front. It won't be too expensive.

Plan on spending a few hundred dollars at a minimum. Just to recharge an empty system with R12 will cost that much. But, more than likely, you have more problems that just a recharge. At the very least you have a leak in the system. Could be a bad hose, bad orings, ......etc.
I have replaced orings, compressor, expansion valve, and drier on two different generations of RX7, and have had good luck with both. I do all the labor, and then I take it to an A/C shop, have them flush it, pull a vacuum, and then recharge it. I last did my FD and it cost me around $800 by the time I was done.
Anytime you open up the system, you should replace the drier, and then you might as well replace the expansion valve (high failure item), and replace the orings.
It's a lot of work, but can be done, but I would leave the rest to a professional. Just be prepared to spend more money than you think.

A lot of auto shops in my area are not using leak sniffers, they use a dye in the refrigerant (r134a in my FD). They start with a pressure test..

Huh? The A/C specialist shop I deal with charges $55 / pound for R12 freon + $40 to evacuate the system. So, an evacuation and recharge of a typical system costs around $150 - $160. Obviously if there's a leak or a malfunction of a component it will cost you more, but even a leaky hose shouldn't result in a humungous bill.

As I say, it pays to shop around.

Diagnosis and repair of your A/C system is not that tough especially if you have r134a. R12 repair can be costly due the the price of refrigerant and the need to hire a licensed mechanic. It is possible to use r134a in an R12 system. It won't cool quite as well and you need to fully vaccuum out the R12 first. This is a really good option if you consider just how much cheaper it is. You can borrow all of the required tools at Autozone for free! I have done r134 repair and recharge several times including on the FD. It's not that tough.

^ That's bad advice about putting 134a in an R12 system, especially in a car like the FD which doesn't have the most robust A/C system to begin with.

^+1
Bad, bad idea. These two refrigerants have different system requirements.

This is correct--and perhaps an understatement. It's a real bad idea. I do not recommend retrofitting any R12 system with R134. Once any A/C system has been operated with a chlorinated refrigerant (e.g., CFC's including R12), it is difficult to sufficiently clean the system to run the PAG oil that is required for R134a. This is no joke unless you want a system full of sludge that will eventually fail. Additionally, there are differences in the materials and elastomeres used throughout the system that are necesary for reliabilty and satisfactory operation, especially over time. R134 might work for a while; however, it usually winds up as a train wreck--that's if it doesn't all leak out first. I'll spare you the chemistry as it's been well covered in other threads, but suffice to say that the performance will be poor and the problems with the system will increase exponentially.

For recommendations on alternative refrigerants, check my posts in other threads including the ones I wrote a couple of weeks ago here: https://www.rx7club.com/3rd-generation-specific-1993-2002-16/charging-c-651033/

I hope this helps.

My '95 came from Mazda with r134a, did the earlier FDs have R12??

Yep. Our 95s have crappy A/C compared to the 93s and early 94s.

On my '95 on a 90+ degree day with the A/C in recirculation mode on fan speed 3 my vent temp runs 40-42 degrees. That's not too shabby. My other car may beat it by 2 degrees sometimes, but the FD's system seems to work well enough. 134a can cool a car just as well as R12, it's just that the system has to be designed to compensate. On the '95, for instance, they put an extra fin on the condenser. If somebody has vent temp readings for their '93 or '94 it'd be interesting to compare.

You can substantially improve the cooling of any R134 system by replacing the R134 refrigerant with an HC (such as ES-12, HC-12, etc.) as I pointed out in another thread (link is above, in my last post). The HC is a drop in--meaning that it is compatible with the materials and oil used in the R134 system and it will yield the cooling power of an R12 based system with no other changes (assuming the system is in good condition). It is also cheap, about $6 a can and you will need two of them for an FD. It really is a win-win situation as there are numerous advantages to running it.

The foregoing is on track. A system purposly designed for R134 can cool well. Because of differences in the condensing temperatures and pressures for this refrigerant, R134 needs a larger condensor and lots of airflow to function well--pay attention to this you front mount guys--I said R134 systems are very sensitive to condensing airflow and many systems cannot get enough air over the condenser at low speeds (even with fans) to provide adequate cooling, especially at idle or a stop.

I'll say it again here: If you're not happy with R134 performance, consider replacing the refrigerant with HC-12 or equivalent; you will not regret it.