The 411 on FD AC fluid?
 

I haven't read alot about it, so could you guys please tell me what the deal with the AC in FD's is? I know it has somethign to due with out of date AC fluid that costs a lot these days. Also, how (if possible) can you fix the problem?

Jim

93 and 94 has the r12 fluid and 95 has the r134a.

ok what does that mean lol. im guessing that 93 and 94 use the out to date and the problem was fixed in 95?

r12 costs something like 50 bucks a gallon, or quart, or something. i belive you can get it converted over for ~400 bucks? i may be wrong

ok what does that mean lol. im guessing that 93 and 94 use the out to date and the problem was fixed in 95?

not really out of date, but they had to start using the R134 by law. R12 before that with the 93 and 94. The r12 requires you to have a license to work with it, R134 doesn't. I just had mine converted over at a local Midas shop for 140 bucks...vacuumed out the old oil, new put in and, new fittings, and filled for that amount...took about 1.5 hours. So the 95 r134 was in response to fixking a problem, they just had to do it. Nothing wrong with 93 and 94 systems, it just costs more to refill and harder to find someone that can do it. R12 cools better. Also 93 and 94 are tending to leak alittle now do to age and oil rings in the system letting the freon out.

Tim

rip the a/c out!

Physically, is the AC system any different in the 95's (bigger condenser, different compressor, etc)?

Bringing back an old thread here, but better than getting flamed for making a new one. Does the 1995 RX-7's come w/ larger condensors in order to compensate for the use of R-134A or do they just not blow as cold and use the exact same hardware?

Haha, I was thinking about making a new thread too...like today. I still don't know if there is a difference. I need a new condensor and if the 95's are larger I'll just figure out how to make one of those work, otherwise either crappy 93' R12 condensor with 134a or retrofit from a different vehicle. :( Anyone?!?!

.

holy triple post

Anybody know if the 95 system is bigger or had both cars to compare cooling effectiveness?

Few things.

R12 freon is Great Stuff. Works awesome, super efficient, cheap to make...you name it. One problem - it's not environmentally friendly. Ergo, R134a - that's the replacement automotive freon. Dunno if it was mandated that cars switch refrigerants, or automakers just saw the writing on the wall and started building 134a into their systems.

R12 is now not in production - that's why it's so bloody expensive. Back in the day you could pick up a can at K-Mart for a few bucks - no kidding.

Can you convert an R12 system to R134a? Sure. The system won't be designed for it, though. R134a operates under a whole different set of parameters - every part of the AC system has to be factored in for it to work well. All new cars have 134a, and it does cool and work well in a system that's designed for it. With a retrofit (134a in a 12 system) the AC will always be cool, never cold.

Can you update to the '95 134a AC components? Likely, might not be cost effective. You'd have to study the parts diagrams and figure out the differences. I know at a minimum you'd need to change all the O-rings out to compatible O-rings to truly have an effective system, and the condenser is likely different. But, there's also 2 different FD AC systems (Nippondenso and Sanden) so it's pot luck as to which will work with what system, etc.

Anyhow, so your AC blows hot and you want to fix it. Here's the options.

1) Fix it and get it charged back up with R12. Most RX-7 AC problems stem from leaks - slow leak somewhere in the system, mostly in the O-rings or in a condenser that ate a rock. Leaks need to be found and fixed properly, the system pulled down to vacuum, and re-charged at a minimum. Might also be worth replacing the expansion valve and receiver/dryer.

2) Convert to an R12 drop-in. There's a number of refrigerant blends that are chemically similar to R12 and work properly in an R12 system - Hotshot, Freeze12, et al. You do need to have an EPA license to purchase it, though. Again, the same deal applies as #1 - you'll likely have leaks to fix.

3) Convert to 134a. Cheapest in many instances, but you'll NEVER have cold AC. If you could figure out the trick to go to the '95 system, it might be doable, but that also might just be slap cost prohibitive.

If you guys want to do some of the work yourself, AC systems really aren't that hard. Finding and fixing leaks is the trickiest part of the whole thing. All of the components of the AC system are relatively easy to access and service - and no, you don't have to pull the dash to remove the evaporator :). Remember, a LOT of RX-7's had their AC's installed by a dealer or at port, and it's designed to be installed relatively quickly and painlessly. You need a few special tools to do AC work - a manifold and gauge set, a vacuum pump, a can tap...that's the bulk of it.

BTW, epatest.com - go get your AC certification in 30 minutes or less and buy all the freon you'd like :). Super easy - I did it some time back, have the card in my wallet.

Hope this sheds a little light.

Dale

I live in Dallas; we have triple digit temps for a few months out of the year.

Conveted my 93 from R12 to R134a a while back. As expected it doesn't cool as well as R12 but I thought I would try it first as it's cheap to do. I'm familiar with ac systems and in doing my conversion I bought the standard R134a adapters for the fittings. I then drained the system of freon and the compressor of oil and replaced every o-ring with an R134a compatible type (actually not hard as all their locations are shown in the manual). I then added the proper compressor oil and pulled a vac. Made sure the system held and charged it up. R134a runs at higher pressures than R12 so if you merely dump the same amount of 134a in you'll overwork the compressor and really shorten its life (this is where all the "my compressor blew up" stories come from in most conversions). You must monitor the pressures when charging the system and if you don't have gauges you're not going to be able to do it right.

Not only is 134a less efficient it also runs "hotter" in the high side of an old R12 system so you must use less of it to keep from running pressures too high; it's a double whammy.

That said: My car will cool fine if you never let the cockpit itself get overly hot while parked. If I leave it parked in direct sun for hours and it's triple digits outside it will easily take 15 mins for the cabin to really cool down. If I can keep the car in a garage or shade so the cockpit is never hot to start with then it will cool right away no matter what the temp. I do have to use higher fan speeds though. With R12 if speed 2 was good enough I have to use speed 3 to get the same cooling with 134a.

I have run it through 1 summer (beginning he second) and it's been alright, but I'm ready to try one of the R12 replacements such as Freeze12. I can convert it in an afternoon again and it should work at least as well as the 134a is now; probably better. The system has been leak free so I shouldn't need to worry about that.

i recently got my car back from the shop, and basically when i push the AC button it just shoots out air, doesnt get cold.

im guessing there is a leak somewhere because it suddenly did not work. also, i get that drop in RPMS when i turn on the AC.

its a 93 too, wish me luck =p

The simple answer is this. IF you have an originally R12 system, you pay $50/pound, and I think the 7 takes 3 lbs, or you put freeze12 in it. Or you convert. I am running freeze 12. It sucked before, but I was running the stock system, and had an underdrive pulley system, which provided less power to the AC system. I'll see what happens with the vmount and going back to the OEM pulleys. Another idea is to vent the hood. The more you can do to cool the engine compartment, the better the condenser will function.

I just got my license...time to buy me some R12!

I just recharged the system with freeze-12 (R-12 substitute) and it blows out very cold air. The whole thing took 15 minutes and luckily there were no leaks. Also, as I recall, I think the system takes less than 2 lbs.

Where did you buy it from?

Interesting... my 94 has R134 - and I know it is the stock system, it still has the stock stickers under the hood. Maybe it is because my 94 is Canadian and that is just another "enhancement" the Canadian spec FDs had. :confused:

Local shop did the whole thing for about $80. That included checking for leaks with a special dye, etc.

Honestly, the whole thing probably didn't cost him much. I used to work at my uncles wholesale autoparts warehouse when I was younger, and those Freeze-12 bottles (30lbs) aren't too expensive. They also sell them in 1 lb cans.

I remember way back in the early 90's when the R12 was getting more and more expensive, they were shooting up like upwards of 1000% of there original price in no time. I think the guy mentioned there about $30 for one pound now, but there illegal. Crap, that would have been a nice investment!

I was pretty sure that all 94's had R-134?

mmmmkay......my question still goes unanswered. dcfc3s kind of implied that the 95's might have different hardware, but nobody still knows whether the FD's that came factory w/ r134a have different hardware?

Anyways, since my last post, i converted my system over to r134a. It was a quick job and I didn't replaced any o-rings, so we'll see how long it's going to last. As a side note, the amount of oil you put in will have a large effect on how cold the a/c will blow. A friend who had some professional grade meters helped me do it and at first we could only get it to blow at 60*F but after removing the excess oil we were able to drop the temp down to 50*F. I'm happy with it for now after having no A/C, but we'll see how it bears over time and against a Texas summer.

Every car in the US sold in 94 or later uses R134a. All 94 Rx7's came with R134a, only the 93's came with Freon.