help! air conditioning issue

[charlesb2003]

ok... i was doing some work under the hood and i noticed that the low side a/c fitting looked like an r134a conversion fitting... the high side was still the r12 one. well i had been told when i bought the car that it still had r12 in it, and when you look in the sight glass with it on you can see a green refridgerant flowing by... but since it had the r134a fitting on it and i just so happen to have an r134a guage, i put it on and it read 100psi! that's well into the red on my guage, the yellow is from 45-55psi.... so whatever refridgerant i have in there... is there too much? or would this be normal for r12? and if it is r12, why the heck is there an r134a conversion fitting on the low side!?!??

[wthramann]

R12 pressures are lower than 134a. Sounds like the system was converted to 134a but the low side pressure is too high. Probably should have it checked out.

[zero.counter]

Yeah, it might need to be evacuated and have the fittings and hoses checked. The see if the conversion was already performed. Bad thing if you leak it on your own, but you prolly already knew that.

[charlesb2003]

just went out and checked the pressure on my mom's which i just converted to r134a, hers was reading 110.... so i was like i know it was right when i put it in.... and then i realized i should prolly be checking it with the air conditioner on

so i checked hers and mine and they're both fine. i think mine's r12 still, cuz i can see the green coolant in the sight glass and it read 25 psi... my mom's reads 30psi with r134a and you can't see anything in the sight glass. now i just gotta figure out why the heck is there a r134a fitting on mine... hmmm...

[njpeter]

static pressures are always high, and forget that it has a sight glass, look for my other posts on a/c for tips

[DBMaster]

Most of the R12 "replacement" refrigerants require the use of R134 fittings (Autocool and Freeze 12 for example). You charge through the low side so all you would need is a low side adapter. The R12 replacements run the gamut so there's no telling exactly what "normal" pressure should be. The green color in the sight glass makes me wonder, though. Straight R12 would be clear. Maybe there's some leak detector dye in there.

Anyway, I was going to ask you about whether the system was on or off when you were checking it

Anyway, if it's cooling, be happy. If the mix of refrigerants is going to be harmful to your system there's not much you can do about it now.

[charlesb2003]

the green color is a uv dye for leak detection... there is a slow leak in the compressor front seal and i believe that's why the dye was added.

my mom's also has a green dye in it, and the reason i mentioned the sight glass is because even tho my pressures are about 5psi lower than my mom's (with the system on ) i can see the green in my sight glass but not on hers... that's why i think mine's still r12.

and as for cooling, it gets good and cold at night and very cool in the hot day, but it takes a long time to cool off inside. my mom's cools off a lot quicker, however mine gets colder than hers does once it finally cools off.

[DBMaster]

Even though not recommended, R12 replacement refrigerants sometimes get mixed in with R12. Who knows, maybe you have ALL R12 replacement in there, or even something else. I can think of no other reason that someone would have put the conversion fitting on your low side valve. If you have the Keihin compressor (there's a little sticker near your radiator support telling you which one you have) front seal leaks are common. That's why I ended up replacing mine. If R134a was put in there the seal leak will get worse because the Keihin compressor's seal material is not compatible. This is a fact.

I am not sure how you can find out if you have straight R12, a mix, or R134a, though. That's one for the "experts" here.

[charlesb2003]

it's a nippondenso...

[DBMaster]

Well, then you should consider yourself lucky there. When I thought about this some more I pretty much decided that you either have a mix, or a conversion refrigerant of some type in your system. There is no other reason that someone would have put the R134 adapter on the low side. Pretty much all of the other refrigerants use the R134 fittings for charging.

R134a will generally run higher pressures than R12 when properly charged - not something you want with a leaky compressor seal.

If you have a few bucks lying around I would recommend a complete evacuation and recharge with a single refrigerant just to be on the safe side. Better to spend a few bucks now than to be looking at a pile of bucks to replace everything in the system if it fails due to mixed refrigerants or incorrect oil type.

[charlesb2003]

thanks for the advice... i'll be doing that soon. when i do, what's the best refridgerant to put in? best as in what will make my car coldest without harming my system. i don't care what it costs...

























...ok i care a little bit

[DBMaster]

That will definitely be R12. If you can go online and get your 609 certification, or know someone who has one, buy four cans of R12 off eBay. The price is coming down now that fewer vehicles use it. Definitely cheaper than buying at the auto parts store. Last time I bought some at NAPA it was $35 a can. On eBay I have seen it go as low as $20.

I like the information I saw on AutoCool

http://www.autocool-refrigerants.com/

Of course, I have not tried it so I don't know how well it works.

[charlesb2003]

i've read up on autocool a lot and i like what i see too... i know 88accordlxcarb likes it.. read his how-to on converting to r134a...

and i found the site to get certified... i'm definately gonna do that.. $15 is well worth bein able to buy r12.

[Techno]

Dude,

Unless you have lots of money...which does not apply to most of us here, I would not be going out to buy R12. DiChloroDiFloroMethane is not cheap as it is no longer manufactured in the United States. I think Mexico still makes it. It is still very expensive.
If you are that worried about your A/C, then take this advice. If you want cold like it was brand new, replace the Compressor with one that does not leak, and then assuming you have the Vacuum Pump, draw the system down to at least 400 microns. That will ensure that you have all the old refrigerant out of the system, and that all the moisture is out as well. If you are able to achieve 400 Microns than you can be well assured that you have no leaks as well. There are several knock-offs out there that claim to replace R-12. There is only one that I have found that well and truly replaces and exceeds specifications of R-12.
That is a product called HotShot 414b.
Couple of specs
R-12 boils off at -21.9 deg F operating pressure 125 +/- 5
R-134a boils off at -18.7 deg F operating pressure --can't remember
R-414b boils off at -29.6 deg F operating pressure 128 +/- 5

Both R-12 and R-134 use differant oils inside the system. Don't try to just 'replace the gas with the other' you will do more harm than good.

R-414b on the other hand is designed to work BOTH the esther and poly oils. You can replace either gas with R-414b just as long as you ensure all the residual is removed from the system and you are sure that you have no leaks. if you have a leak in the system with R-414b, the refrigerant will fractionate and you will be left with esentially nothing.

And BTY way...You would use 20% less of HotShot 414b to do the same job. (i.e. instead of 20 oz. you would use 16 oz.)

Techno

[Techno]

Oh and to get certified to handle Refrigerant...Takes lots more than $15. Just the test alone is $30 not to mention learning the stuff. That is just the test for handling Refrigerant. If you want to buy small cans for your car...you will need a seperate lisence to buy the small cans. That test is harder and costs roughly $50.

Don't take the test unless you KNOW the material. Expensive to take test over and over again.

Techno

[DBMaster]

Well, guys, I DID pay only $15 to get my certification. I just happened to know the HVAC instructor at a local community college. I watched a video and took a test that was not that hard at all. I did not have to be in the class, but the $15 charge applied to his students as well. Of course, I did it in 1994, but now there are a lot more places to do this.

I am aware that R12 has not been manufactured in most first world countries for several years now, however, manufacturers stockpiled the stuff before the ban. Add to that all of the stuff that was bought by individuals who no longer need it due to getting rid of their old cars and recycled R12 that will be available for years to come. There is plenty of R12 out there and the prices have stabilized and started coming down. Hell, I have three cans that a friend from church just GAVE me three years ago. There are a lot of folks out there who have cans on shelves in their garages that they bought for $0.79 back in the 80's. Ask around. My next door neighbor says he has a few cans buried in the garage that he will dig out and give me if I ever need them.

It seems like everybody has their favorite refrigerant for these old cars. With all the stuff that is out there there must be a few good ones. I still don't think the $30 R134 "conversion" kit from Wal Mart is going to cut it for anyone who wants to be keeping their car for years after they do it. I think that is just a quick fix to give you marginal A/C for a year or two. Would you agree?

[Mac]

I agree. Our cars A/C was designed for R-12, and that is what works best in them. A proper conversion would cost alot of money. Best is to find any leaks, repair them and draw a nice long vacuum and recharge with R 12.

There still is alot of 12 out there , you just have to find it. Someone just gave me a 30 lb. bottle with about 7 lbs. in it because they didn't need it any more.

[DBMaster]

Man, when I think about the BB machine gun I bought back in 1985 that used Freon as a propellant. I remember picking some up for 50 cents a can at a Kroger store when they stopped carrying it.

If your system is in good shape you won't need much. A little over three cans to charge it. Mine still ends up needing abou half a can each spring even though all the leaks are supposedly gone. Even a $35 a can I can afford to add half a can each year. I have a high quality tap valve that allows me to retain the half can I don't use without the gas leaking out. I remember the el cheapo tap valves. If you didn't use up the whole can it would leak out within a few days. My charge kit has an gauge in line. I use that in combinaion with an A/C thermometer in the center vent to get the optimum charge.

A good tip is to use a bucket of hot water to keep the can from freezing up while you are charging. It has worked well for me over the years.

[Mac]

Yep. Years ago anyone could walk in your local K Mart and buy a can of R 12 for about buck. People still got them in their garage and have no use for them. R 12 doesn't go bad , so if you can find some grab it.

I just replaced my condenser because it was leaking, and the expansion valve was also leaking so I changed the O rings. So while I had the system opened I changed every O-ring in the system. I also changed the coil on my compressor. Wasn't nothing hard about the whole job. Pulled a good vacuum. I just ordered a set of R 12 manifold gauges and as soon as they get here I will recharge with the free R 12 I got. Then I should be good for a long time. I will also have some left over 12 to top off when needed.

[86LXi270K]

Freeze 12 is actually 80% R134a. So if you do have a kehin compressor you might want to consider pulling it out before you destroy the compressor.