[s-cars] Re: RE: ac recharge port

David duandcc_forums at cox.net
Thu Jun 30 14:45:18 EDT 2005

This should also help for those thinking of converting. It's the original notice sent to Audi dealers back in the mid 90s when coversions were all the rage and provides step by step instuctions with part numbers:


Now, I've done the R134a conversion to my Coupe GT and to my old 1985 Impala 9C1. What are my thoughts? First you have to decide whether you can live with an AC system that will never cool quite as well as it did with R12. Audi does not recommend converting any car with the York Type compressor with good reason (some other compressors can be converted easier, but I have not BTDT with any of those). I had mine converted and it was a nightmare, but worked out in the end. On R12, from what I've heard, you should be getting vent temps at or below 40*F if the system is working properly. I've found that if you adjust the AC thermostat you can get even lower temps. My R134a converted system eventually gets down to the mid 30s. But it takes a LONG time to get there, 10+ minutes for so on a hot day when interior temps start high. An example would a while back when I left work. I hopped in the car and the vent thermometer (I just keep it in there) was showing 120 degrees. It took 10 minutes for so for the vent temps to drop to 50 on #3 blower setting (takes even longer on high). It hit 45 degrees within another 5 minutes or so. But when it's 95 degrees out with high humidity, even 50 degree vent temps feel pretty good! So, do you think you could live with a slightly less efficient system?

Now, onto the worst part, the conversion. First, if you are going to do this, do it right. That means replacing: service fittings, dryer, all o-rings/seals, and the expansion or oriface  valve. Then flush everything (have to remove the compressor to flush it). Now evacuate and make sure it will hold a vacuum, now refill with ESTER or PAG oil and fresh R134a (ester is R12 & 134a compatible and it is a good conditioner of seals and o-rings) and keep you fingers crossed.

Now that everything is converted, I'd consider adjusting the AC Temp Sensor (not sure of the large Audis have them, I know the typ 81 & 85 do). This is the sensor that controls at what temp the compressor cuts oput. The factory setting is around 42*F. I've adjsuted mine down to 34*F and am very happy.

To adjust the temp to a 4000 or Coupe GT:
Remove the glove box as an assembly and lay it on the passenger floor. The Fuel Injection computer is attached to the right side of the glove box. Leave it there because you'll want to run the engine and drive the car around.

With the glove box removed you'll be looking at the Evaporator. To the right of the evaporator is a small box, gold anadized in color, with a 14mm nut facing you to hold the box in place.

This is the temp sensor for the evaporator core. Take note of the ether filled capilary tube that comes out the top of it and goes to the left across the front of the evaporator and then into the fins of the evaporator. Break this tube and you're screwed......so proceed with caution!!!!

Undo the 14mm nut that holds the temp sensor switch in place. Lower the temp sensor and bring it and it's capilary tube outward just unit you can see and get to the top of it.

On top you'll see a philips screw. This is the temp adjuster screw. Scribe a line on it and on the housing for reference.

Turn the screw COUNTER-CLOCKWISE to lower the tempurature at which it turns off the compressor.

As I said, mine was blowing 43 degrees. 2-1/2 turns COUNTER-CLOCKWISE got me to 30 degrees.

So, make your adjustments slowly with the car sitting there running, doors and windows closed and see what you get. Take is slowly.

Once you get where you want. Go for a test drive and see what you get on the road. I noticed I had to keep turning the screw counter clockwise a bit further to get 30 on a test drive.....as compared to what it took to get 30 in the driveway.

With it torn down this far, it would be a good idea to remove and clean the evaporator drain pan.

One thing to keep in mind, R134a molecules are much smaller than R12 and will find even the tiniest ways to leak out. So if your hoses are even marginal, those will have to be replaced too. Doing a R12 to R134a conversion properly is pretty expensive. My conversion including a new high pressure flex hose and all the things above was over $700 (done by a local mechanic, not me). Others may tell you to just go to your FLAPS and buy the $35 conversion kit. Sure, it might work, but from what I've experienced, it won't work well or it won't work very long (I did the 85 Impala this way and the best I can get is about 45-48*F air output). One other thing, make sure your radiator fan is healthy (works on all speeds if multi-speed and pulls well). It would also help to put a pusher fan in front of the AC condenser to added air-flow over it.

Overall, I guess I'm satisfied with the results. It works adequately and will make future recharges dirt cheap when compared to R12.

Well, sorry for the novel, but HTH, YMMV. Good luck.

1987 CGT 2.3

> From: Eric_R_Kissell at whirlpool.com
> Date: 2005/06/29 Wed AM 10:19:35 EDT
> To: "Schaible, David" <David.Schaible at jrspharma.com>
> CC: s-car-list at audifans.com,  quattro at audifans.com, 
> 	200q20v at audifans.com
> Subject: RE: ac recharge port
> 'tis the season of AC threads, so let me post this now in hopes of helping
> others with AC questions. DIY AC work is not that difficult, though you
> must take care to contain any refrigerant such as R12 (or R134A for that
> matter) to be nice to our environment.
> Information about DIY AC charging may be found at:
> http://www.aircondition.com/wwwboard/alternative/current/7842.html
> http://www.autoacforum.com/messageview.cfm?catid=20&threadid=7931&FTVAR_MSGDBTABLE
> =
> http://www.autoacforum.com/messageview.cfm?catid=20&threadid=9172
> and discussions about alternative refrigerants are at:
> http://www.aircondition.com/wwwboard/alternative/index.htm
> http://www.autoacforum.com/messageview.cfm?catid=20&threadid=9171
> I have converted to an alternative refrigerant. I am in no way affiliated
> with any alternative refrigerant supplier but I am a satisfied customer of
> the following:
> http://www.es-refrigerants.com
> Read their info and their FAQ and see if you think this is the way to go. I
> have had good luck with two cars.
> http://www.es-refrigerants.com/faq/
> http://www.es-refrigerants.com/reports/
> Get a set of decent gauges from Harbor Freight for a decent price ($50). I
> got a R134A guage set. I understand that regulations require system
> conversion (i.e. fittings) to R134A before an alternative refrigerant can
> be used, so I got the R134A set and converted the fittings on my old Audis.
> This way I can also work on newer cars with my AC gauges set.  Conversion
> fittings are available from your FLAPS or online at envirosafe or acsouce
> or ackits or azmobileair. Some cheap fittings may leak, so look for a
> little bit of quality (I am not sure what the FLAPS carry).  Gauges similar
> to the ones I have can be seen at:
> http://www.harborfreight.com/cpi/ctaf/Displayitem.taf?itemnumber=2435
> Harbor Freight also has an inexpensive ($8.99)  compressed air driven
> vacuum pump that was adequate for my conversions to envirosafe.
> http://www.harborfreight.com/cpi/ctaf/Displayitem.taf?itemnumber=3952
> It does not pull "deep vacuum" but it pulls enough for what I needed. You
> can also use the inlet side of various compressors to pull vacuum.
> A Mastercool Auto AC Basics manual  is available from www.acsource.com and
> www.azmobileair.com - The manual has, among other things, some diagnostics
> telling you what to check for various high-side and low-side gauge
> readings.
> http://www.acsource.com/index.asp?PageAction=VIEWPROD&ProdID=8
> http://www.azmobileair.com/index.cfm?fuseaction=Manual
> I agree with the advice to look for leaks if the system is leaking down.
> If you buy envirosafe refrigerant, get the stuff with leak detection dye in
> it (called "dye-charge" on their site). Not only does the dye help you find
> a leak with the proper detection light, it also is able to be shipped
> without Haz Mat issues due to a technicality that the dye enacts.
> http://www.es-refrigerants.com/products/details.asp?id=31
> Also, envirosafe has a nifty and inexpensive little plastic oil checker
> that can be used to evaluate whether your current oil charge is sufficient.
> I think they must have invented it because it is a pretty clever idea that
> I have never seen anywhere else.
> http://www.es-refrigerants.com/products/details.asp?id=169
> I have 1986-1991 Type 44's. For charging with envirosafe, I have found that
> the best place to connect the low side is at the compressor. The high side
> connection is in front of the radiator.
> Let's not start a alternative versus traditional refrigerant thread here. I
> am a believer in alternative (hydrocarbon) refrigerants. I also have a bit
> of experience in refrigeration (see email addy).
> HTH,
> Eric Kissell
> _______________________________________________
> quattro mailing list
> quattro at audifans.com
> http://www.audifans.com/mailman/listinfo/quattro

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