Is your A/C struggling? Freon recharge tutorial
 

Repost from dognmonkey with some extra info by myself and corrections:

Well, our A8 has 159k miles now, and the freon doesn';t hold any more, every year @ summer time, we have to take it to the shop to get freon charge and each time it's $70.00. Now we do it at home for $4.00.

The only way that you can charge Freon to any car is from the LOW port. You can do this with any car, but for the Audis, they covered the low port with some types of sensors. On my A8, the sensor wasn't there, but the connector is. The location is next to the brake master cylinder and in front of the auxiliary fuse/relay box.

For Audi A8s, you need the adapter like this FJC6016
[img]http://ecx.images-amazon.com/images/I/11Ww3F%2BDHcL._SL500_AA300_.jpg[img]

You'll also need a can of 134a freon. You can buy all the materials you need from wal-mart(at least at mine) for around $25

Turn on the engine, turn on the a/c max, screw the pin of the freon connector hose all the way in to punch a hole in the can, unscrew the flow valve slowly all the way for the freon to get out and flow through the hose. You can feel the can getting very cold, leave it for a while, shake it a few times for the freon to get out completely. When the can is empty, feels lighter and the can doesn't get cold anymore, that’'s when the freon is totally out. Turn off the engine, remove the connector, you should be able to feel the a/c inside the car, it will be very cold!

http://www.dognmonkey.com/media/a8ac/ac3.jpg

A few more comments.

1st, I notice the photo from that site was pirated from the original post on QuattroWorld, here >>>

http://forums.quattroworld.com/a8/msgs/15213.phtml

2nd, the sensor on prefacelift D2's at that location is the AC low pressure switch, which was relocated on the facelift models...same fill valve though.

3rd, and the most important thing left out of both procedures, is that since that can is about 400gms of R134a and if you need most or all of it, your system was half empty...750-800gms is full capacity. I would not consider adding that much freon without adding a measured amount of oil charge with it.

When you find a leak point for freon, you'll notice that there's oil at that spot...that ain't freon. It's the special oil that circulates constantly with the freon to lube the compressor...it does not go to the compressor and stay there...when you lose freon, you lose oil.

When I recharged mine (about half empty) I used a pre-mix with 11 oz of freon, 2 oz and 1 ounce leak seal (if you lost freon you have at least a small leak)...total of 14 oz = about 400 grams. WalMart has a great selection...better than auto parts stores I checked...and cheaper.

The whole system is supposed to contain about 4 oz (113 gms) of oil...you may "get by" with only 2 oz left, but I wouldn't do that on purpose. The compressor gets NO lube from anywhere else..it is only lubed by the oil charge.

Oil charge can be purchased and added separately, thru the same port as the freon.

Hey great reply and good tips, I too stumbled across paul's photo on that forum and thought it looked eerily familiar. I had no idea about the lube and oil thanks for the reply

I have a 99 A8 that is cool, but not cold. These cars are factory 134a correct? I'm pretty sure all cars had to be 143a by 96, right?

I know everyone from the older generation interchanges 134a and freon, I just want to make sure we are all talking about the same thing here. Freon is awesome for AC, but the stupid ozone can't handle it, hense 134a...

I have a 93 Mitsubishi with freon still. LOVE IT! Not sure i can even get freon anywhere anymore.

Yep, "freon" is just a general term that I (for one...and others) use to cover all refrigerants...easier to write and spell. When being specific, every type has a number...D2's use R134a. Your older car uses R12, which is "outlawed" in vehicles now and SUPER expensive to buy, since any R12 you find is generally old stock or actually recovered from converted systems...in fact, you actually need an EPA license to even buy it or cheat your way around that somehow.

You could likely find someone who would pay you more for your recovered R12 than what it would cost to replace it with something better >>>

No affiliation, but I would do a commercial for this stuff...ES12a. I lost all my R12, through a high pressure hose leak, in my 1990 Passat (205K miles)...all original AC components and still are after my repairing the offending hose and recharging with this stuff....BLASTS cold air. All I had to do was add a screw-on R134a fitting directly to the R12 low pressure fitting (no need to remove R12 fitting and takes all the same fittings as regular R134a)....THAT'S IT!!

The following is what's unbelievable, but true...I've had it in for a year now...NO problems >>>

-Does not require a vacuum to put in an empty system..in fact, vacuum NOT recommended.

-Does not react with oxygen, moisture, traces of old refrigerant or old refrigerant oil...SO >>>

-No flush required (just discharged system)

-No new dryer required, unless the old one was already bad...I'm using the OEM dryer (22 yrs old and 205K miles)

-Takes less to fill system

-If your compressor used 5hp to run with R12, it'll take 2-3hp to run with ES12a..it's much lighter weight.

-It's Cheap

-It runs MUCH colder than an R12 system converted to regular R134a

Win, win, win...

I learned about it and bought it from these guys >>>

http://autorefrigerants.com/Envirotechnical.htm

As with ALL refrigerants, use the proper oil-charge when you refill...oil or oil/freon oil/freon premix (they sell it and explain it) goes in FIRST with an empty system...otherwise you could destroy the compressor. Too many people incorrectly believe that adding freon alone is OK...NOT TRUE, even with a partially discharged system. When you lose freon (refrigerant of any kind), you lose an equal amount of oil!!!!


...Now, somebody send me a check! :{)>

Interesting stuff... I have about half a 30lb container of R12 still, and the manifold/gauges etc.... :) (Used to be a tech you see....)

But today, that's all illegal, and I if were to use it, I would be, or could be fined by the EPA.

Insane, but true.

What's more, the EPA did all this on the idea that Freon (brand by DuPont) R12 caused large holes in the ozone.

Only there is one little, itty bitty problem with this theory.

R12, or all types of Freon for that matter, are much more heavy than air. (Oxygen/Nitrogen and trace gases like water vapor, methane, carbon dioxide etc.)

So, Science majors! What happens when something is lighter than air? It floats. What happens when something is heavy? It sinks.

So where does the heavy Freon go? "
Where is Ozone?

LOL I'm busting a gut here folks! The serious nature of this total lie is that Freon R12 never could have caused the Ozone to become full of holes, it's too heavy, and goes down storm drains, or hangs out on the floor/ground, not soaring up out of the troposphere and way up to where the Ozone layer is..

SO, why did we replace DuPont Freon R12 with R134a?

Well, it's about this simple. Economics and public policy. It's easy to tell people that R12 causes holes in the Ozone, and sure, if it was there, it would cause holes! So better get that dang, evil R12 out of the ozone layer right? And what better to fill the nations AC needs than a new form of Freon that is not as effective, so you need more of it... Oh wait, you mean DuPont can sell more R134a than R12? And it can get massive mark up on R12 for a few years, and the folks know it will be limited in sale in the USA? (You can buy it cheap in Mexico, or around the world where it's still used BTW..)

So, the EcoFreaks are happy to have evil R12 removed from the land, and good, ecofriendly R134a comes along to save the day. (Of course, it takes more of it to fill your system, and your system has to be larger to provide the same amount of cooling.. taking more energy to run it... your gas mileage going down is good for oil sellers you know...)

And the entire automotive industry has to change over to the new system, and new machines, since we can't let any escape! (Heavens, no, the storm sewers would be full of escaped freon!)

So, back on topic! LOL

I used to have R12 vehicles, and so I kept my own personal supply of R12 that I never ended up having to use... And of course, my gauges/manifold that I used to use all the time along with it... (Illegal to use them now unless I step over the border into Mexico, then it's no big deal....)

Since you know that the ozone layer gives a crap about country borders right? LOL


Oh, and I second all the notes about using the right oil. A compressor without oil will fail in short order. And further, the oil really helps to move the freon around, since being a gas, it's tough to pump folks! (Even compressed into a liquid state, it's not easy to pump, but that's the process that allows it to create the nice cool evaporator you want on a hot day, or a humid day..)

PS: I know that Freon breaks down in sunlight, and that the building blocks of freon can, and might make it up to the Ozone, but then again, so might my nasty Taco Bell farts, and guess what? I don't think it has any measureable effect on the atmosphere in total. :)

Big Business.. ain't it great??
 

It's all about money.

Dupont's patent ran out for R12 and the rest of it is history [well stated above]..

Another DuPont story about PTFE (Teflon).
Not long ago papers were written (by DuPont) stating that using teflon in an internal combustion engine would not work. DuPont have raised the price of their (Teflon) powders
and you need to get in line to buy the stuff and YES, blended properly Teflon does work,
(in any application needing improved lubricity).

Like Edith Ann says, "that's the truth!"
pc

Remember the R134a tank adapter.

You will need it, as the parts guys at the local NAPA and other parrs houses don't have a clue, and I was not paying attention, or I'd have thought to get the TANK ADAPTER.

Dang Audi, why the crap did you not just put a standard low side R134a fitting on the suction pipe? Argh!?!

End of rant. Get the adapter. Go to WalMart, enjoy cold AC for little amounts of cash. (And get "freon" R134a with oil in the can, it's only a few bucks more, and as noted, you will save your very expensive compressor from an early death.)

So my car (99 A8) never had a low pressure switch installed when I got it. Would this be a reason my AC doesn't get cold? What is the purpose of this switch?

Also, I got the adaptor and some dimension on it must be ot of spec with it, or the AC recharge can because i doesn't push the pin far enough to let the R134A in.