My AC Repair Plan
 

Story: I bought my 91 about 3-4 years ago and it was advertised with the AC not running, which I didn't have a problem with since it was so cheap ($2K). The button on the console could not be pushed in, it was obviously broken.

A month ago, I replaced the console only. Crossed my fingers, pushed the button. The AC light came on and the idle dropped as I heard the compressor switch on. 5-10 minutes of fast idle later and my quick fix dreams were shattered.

So I ran across this thread on the pointy board,
http://forum.miata.net/vb/showthread...highlight=r-12

The part that got really got my attention was Crash41301's posts. So, he commences to be flamed by the HVAC nannies and I shoot him a PM.

Hell, I've got nothing to lose, AC already doesn't work. This sh1t might even work better, and I don't have to change the oil or fittings. Score.

I ordered the Master Recharge Kit from Autorefrigerants.com and the "Boss" portable propane torch b/c fire is cool.

Attachment 211092

My next steps are: I'm going to check the charge with my new HF r134 gauge.

If there's a charge, I'm gonna go get it evacuated properly like a good boy (hey I run a high flow cat too :fawk:).

No charge, and I'll go rent a vac pump from Autozone. Then cross my fingers there's no leaks. It'll suck if there is major leaks. I'll hold the vacuum for about an hour, and then check it again. And if that goes well I'll charge the system and add the can of included Proseal in also (might do this anyway if I don't find an Oring leak).

Thoughts, opinions?

Chris

Crap, gauge didn't fit. Guess I'll have to return it and find another one.

Chris

I have a compressor and condensor if it turns out to be more than just charging issue. ;)

Im deff curious to see how it works out. Down here in south Florida my a/c is pretty useless also.
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how much do compressors usualy run?

get a shop to flush the system first.

$200-$300 from what I've seen.......
Mine is not new - but ain't that 'spensive either.

I've got the entire a/c system (short of the hvac controls in the cabin) in my garage if you or anyone else needs something.

What do they do when they flush it?

If you mean take out all the lines and clean them, then no, I'll probably not do that.

If you mean get rid of any leftover R12, I plan on it if there is any pressure in the lines.

Chris

Well, your description wasn't completely clear when you said:

If "shattered dreams" means your compressor took a shit, then it's likely your system is well contaminated, in which case you'll want to heed the advice of akaryery lest you may destroy your replacement compressor and other such system components.

No I meant that fixing just the button didn't work. That was my quick fix dream.

Compressor sounds to be fine, kicking on and off without a problem.

Chris

EDIT: the "blown up" tag is an allusion to being blown up by a flammable refrigerant.

Oh, then you should be fine. Replace the dryer, pull a vacuum, put the factory spec'd quantity of mineral oil in the compressor (not in that order), and recharge with HCs and - assuming all other system components are sound - you'll be blowing snowflakes.

I've used a combination of propane and isobutane as a refrigerant with outstanding success (in a non-miata R12 system). Never used Envirosafe but it's my understanding that it's primarily propane with their own odorant added.

At what point should I add the oil, after vac checking?
And, should I put the proseal in prior to the refrigerant as well?

Thanks,
Chris

The vacuum portion of the AC recharge process isn't merely a "check." It's a critical part of the process.

I don't know what proseal is

I would like to help you but based on many of your questions, it seems that you may not be prepared to be working with compressed flammable gases, much less be installing them in a mobile AC system. For this reason, I cannot advise you further. However, the folks in OZ have been using propane cocktails in mobile AC systems for decades so I suggest you find one of their forums for further information.

I know with flurocarbons there needs to be 0 vac so that there is no moisture/oxygen. However, the autorefrigerants site states:
"#2 If desired, pull a vacuum. After pulling a vacuum of no more than 10 inches, do not charge under vacuum. ENVIRO-SAFE does not become caustic if some moisture is present. Charging under a high vacuum can result in an overcharge. Any overcharge may cause loss of cooling efficiency.
# 3 - Connect gauges and hoses. With compressor off, open cylinder valve or invert can to install ENVIRO-SAFE on low-pressure side of compressor (installing as a liquid will not harm the compressor). Establish flow. After an initial minimum charge is achieved, start compressor and set system to high. Continue adding ENVIRO-SAFE as needed to achieve proper pressure level according to manufacturer's specifications. DO NOT OVERCHARGE! Exceeding 60 psig on the low side may damage compressor. In some cases, clearing the site glass overcharges the unit. Any overcharge may cause loss of cooling efficiency. "

Proseal is their leak sealer. I'm not 100% sure if I should put it in before or after the refrigerant.

Chris

If you have R12 gauges you can get Freeze 12. You don't have to change the oil.

The problem is that vacuming doesn't pull out the oil. Or so I was told.Hmm... But anywayThey say that the R134a mixed with the R12 oil causes the oil to gum up, and stop the flow resulting in FAILURE.
I said who cares and just put it in anyways. It has been working good for 4 years.

I'm not telling you to do it. And later you may have problems. I may just be lucky.

And as far as the fitting. They sell a R134a conversion fitting from $4 up to a $12 kit for multiple adapters to fit all cars and years.

I'm cheap, and may be tearring it up, But I'm not sweating. I didn't even vaccume it down.
I just bought the R134a can with the reuseable gauge attached and prefilled oil. And bought an extra can.

$38 and it is freezing.

The fittings came with the kit.

HF has a AC manifold gauge set for $40, or I can rent one from Autozone for $100 (deposit). Autozone also has the vacuum pump for rent for $200 (deposit also).

Chris

Holy shit. I'm ignoring everything in this thread and offering my advice on A/C repair.

If the system has been open for any amount of time, it is contaminated. That means if a hose has been off, or a leak, or the compressor blew up, or half the shit was missing for 4 years, then it's contaminated. You will have to flush it. I would flush it anyways. So flush it.

Change all the O-rings. Just do it. They're like really inexpensive and not overly difficult to change.

Pull the compressor apart and clean it up. New O rings, etc. Reassemble. Pour say 2 oz of new oil in it and spin it by hand to prime it up.

Install a new drier/accumulator/receiver. You can pour the rest of the oil in it. (if it holds 5.2 oz, and you poured 2 in the compressor, then dump 3.2 in the receiver.)

Pull a vacuum on the system for an hour. Shut the manifolds and wait say an hour to make sure it's not leaking. If it's leaking you will loose vacuum. If it's good, proceed to charge it with R134A. Put whatever amount in ounces it calls for. My miata takes 22 oz of R134A and 5.2 oz of oil IIRC.

Then it works. You have not wasted your time and money fucking with it to "hope" it fixes it, and you car will blow air like it did when it was new. (well, actually R12 is a bit better, but...) There's no way in hell I'd do it any other way. Waste all you time and money and end up failing or doing it 3 times to get it "decent" with a guesstimated amount of oil and suboptimal cooling.

Also, if the car's got over 80K on the clock, I'd suggest cleaning the condenser (the front mounted heat exchanger on your car) and the evaporator (the one that's inside the cabin, in the HVAC system under the dash). They get dirty, and cleaning them does wonders. It gets that smell out out that so many car A/C systems have. Cleaning the front condenser usually helps too.

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