merc 93

Can I do it myself?
If so, how?

FDSeoul

iTrader: (8)

what system are you running??? R12 or has it been reto-fitted with the new system???

If the system is R12 (OLDER System/colder/better)you 'll need to get in contact with someone who has a license to buy this stuff.

Other wise the newer system stuff can be bought buy the can at any auto store and just follow the install instruction on the bottle.

merc 93

Original equipment on everything under the hood, except belts, so R12.
Getting my online certification to buy R12 refrigerant, but also need to know what else I will need to just recharge the system.

I can spend $20 on getting certified and $40 for refrigerant but not $200 or more to have someone else do the same and more.
Can I and should I also replace the dryer? Other cheap parts too?

Thanks for the help!

bajaman

Go to eBay and get the refrigerant (r12), it is readily available.
Why is your system discharged? Need to figure that out if that is an issue before anything else.
STAY WITH r12! You will be MUCH happier.

FDSeoul

iTrader: (8)

you should try to see if the system is in good working condition first!
your need the see if the system will hold charge, the only way to do this is by charging it first and seeing if there is any leak. Sounds simple enough to charge the system it self is pretty easy. Read the FSM manual and it will clearly show which of the two nipples you nee to open for the charge process.


here is what i ended up buying to recharge my system and it still blows hard and cold after 2 years of use

IMG_3160.jpg?t=1207771925

FDSeoul

iTrader: (8)

This should work

http://cgi.ebay.com/ebaymotors/Freez...Q5fAccessories

merc 93

Wow, thanks guys!

The A/C needed to be recharged and then worked fine for a few years the last time I had this car running on a daily, err yearly basis back in 2005 or so. At that time, I took it to a Mazda dealership and after alot of testing and alot of labor charges, they said they could find no leak.
I am sure there is a slow leak somewhere but it will be much less expensive for me to charge the system every couple of years than to pay someone to find a leak and then fix it.

Thanks for all your help as I am becoming a RX7 mechanic system by system. :-)

JM1FD

iTrader: (1)

Since the system has been down for several years, you should make sure the compressor will turn by hand easily. If it will turn, then you should go ahead and replace the dryer and recharge. Check the shop manual to see how much oil you should add back in when replacing the dryer. Be sure to use mineral oil not PAG/POE.

After you've got the new dryer on, pull a deep vacuum and then recharge into the vacuum with 2 cans of R-12. Don't use one of those shitty compressed air operated venturi pumps...they don't pump down low enough.

mecman

iTrader: (11)

I just put a can of R134A into the system and it works fine. Any retro fit kit can purchased at most any auto parts store.

Speed of light

iTrader: (8)

Otherwise fine, intact and leak-free Automotive a/c units often leak out through the compressor shaft seal over time. Within limits, this is normal, and not indicative of a problem.

Expanding on JM1FD's previous post, the most important thing you can do is pull a hard vacuum on the system for 30 minutes or so at > 29" Hg. Subsequently disconnect the vac pump and let the system sit for a while and see if it will hold the vacuum. If it stays down under 29" hg for 10 minutes or so, you're okay for an automotive system. If it does not, then you have a leak (or the system is filled with moisture-but not as likely). There is a gotcha here: a/c compressor shaft seals are designed to seal under pressure and may not always seal well under a vacuum--so it is possible that a leak while under vacuum will not necessarily leak under pressure. Accordingly, such system may still be serviceable and you will have to determine this through trial and error. (NOTE: 29" Hg is relatively crude standard and not a good enough for electrically operated hermetic compressors such as your home ac unit.)

If the system has not been open for any appreciable time, then your drier should be okay. Any moisture in the system will flash out when you pull a hard vac. (I also suggest doing this when everything is warm to increase the efficiency of the vac process.)

If clean R12 is reasonably available, I would use it. If not, there are some alternatives, especially for those already converted to r134. This thread is an interesting read: https://www.rx7club.com/3rd-generation-specific-1993-2002-16/c-gurus-what-say-you-about-freeze-12-a-664882/

I would not recommend a 134 retrofit to anyone as the system really needs to be redesigned to work efficiently with it. Conversions to 134a really don't cut it and you probably will not be very happy with it; industry reports suggest most people aren't, regardless of their vehicle. The FD a/c is capable of excellent performance with the proper charge of an appropriate refrigerant. That is, provided you don't have a FMIC. With an FMIC you cannot get enough condensing airflow for proper system operation, let alone cool the radiator, lol.

Under no circumstances should you attempt to reintroduce R12 into a system that has been converted to R134. The chlorine compounds in the R12 will react with the PAO/PAG oils used with 134 and you will end up with a hell of a mess. If the oil in your AC system is a fluorescent green color, then you likely have a PAG/PAO oil.

JM1FD

iTrader: (1)

Do not use "retrofit kits" These are referred to as "death kits" in the auto a/c industry 'cause they will KILL your system after a season or two of operation.

JM1FD

iTrader: (1)

This is the only thing I disagree with...the dryer has been absorbing moisture for 15 years and is probably at or near the point of saturation. Driers for the Nippondenso systems are SUPER cheap...driers for the MANA systems are only about $50. It is cheap insurance. Just do it.

oppa637

iTrader: (6)

subs

RotorDream

I'm gonna have to call bullshit on this one sir. the only company that still makes dryers for the MANA system is ready-aire. part no. 4016 from shop.orilley.com
and they are $75 plus shipping. not only that, but where the 0-rings seat on the new dryer is a sharp corner and not curved like on the OEM dryer, therefore to have it seat correctly, (unless you wanna cut corners and be lazy, btw not a good idea for our cars) requires that you take it to a machine shop and have them bevel the edges so the o-rings seat properly. This costs about one hour of labor to ensure that no metal shavings get down into the dryer (bad mojo if this happens).
So that means tacking on another $50-80. bringint the total cost of the MANA dryer to $125-155.

JM1FD

iTrader: (1)

That's odd...I'm finding that drier for $57.99 (About $50)

So, O-Great-All-Seeing-All-Knowing-Drier-Modifier...precisely what are the ramifications of not having the holes in the drier chamfered? How do you know you didn't just get a dryer that the factory forgot to chamfer?

Nevertheless...even if it was a $150 part it is still cheaper than having to replace the system because the refrigerant got wet and decomposed into hydrochloric acid, eating holes in various system components.

RotorDream

ok, ill give you that it was ~75 including shipping, but other than that:

57.99 would round up to 60, not down to 50, but its ok, not everybody pays attention in 3rd grade math. just kidding but seriously, i didn't go out and just randomly spend ~70 bucks to modify the dryer because i was bored. I had the shop try the dryer as it was delivered, and what do you know, the o-rings didn't seat correctly, imagine that! it held vacuum, as the o-rings were being pulled into the gap allowing it to seal, but as soon as they began charging, the refrigerant began to leak from the dryer. after this happened I decided to see if "the factory forgot to chamfer" it and after contacting the customer support dept, i was told that's how it was made. do you really think I would pay for the same part twice just because I didnt want to send it back and get it replaced? come on now. but in the end i am very satisfied with the outcome, and agree that the 150 was worth it just to be on the safe side, as the other possibility would be much worse.

JM1FD

iTrader: (1)

In your other thread you made it sound like you didn't actually try to assemble & charge it with the un-chamfered dryer.

The pic of the dryer on the CSK/Oreilly site looks like it has chamfered holes. The pic of the dryer on the Ready-Aire site also shows chamfered holes. Did you talk to somebody at Ready-Aire or Oreilly?

bajaman

Are you saying you simply changed the fittings on an existing r12 system to r134a and then just added a can of 134a into an r12 system?

I can't imagine doing that....the refrigerants are incompatible with each other.

RotorDream

Well I didnt know i needed to post everything that didn't work in my thread ill remember that next time, sir. and neither of those pics are clear/high resolution enough to see a chamfer, infact the sharp line of the shadow in both of them would show that there is a sharp difference in angle instead of a slow change in lighting more common to a curve. If you are talking about the recess then I'm sorry to tell you your mistaken the inlet and outlet are recessed into the top about an 1/8th of an inch. this recessed ledge is what needs to be camfered

edit: i talked to orelliey and they told me they contacted ready-aire about this previously.


and baja i too really hope mecman didnt charge r-134 into r-12. the refrigerants aren't whats the main problem, its that the r-134 will eat away the o-rings used on r-12 systems and the oil used for r-134 (that is usually included in the DIY cans) will not suspend in the r-12 and vice versa which causes the oil to "puddle" i guess would be the best way to describe it in the compressor and the dryer, which leads to very bad problems.

RotorDream

heres a really crappy pic just incase my description was unclear.