Herb--

I asked the dealer about converting my 1985 Jetta TD to r134. They said "bad idea". They pointed out that the 134 molecules are smaller and often leak out of the tubing used in r12 systems. Also they said the evaporator and condenser coils on newer r134 systems are designed differently.

Essentially, the old AC systems from the 1950's and 60's had round tubes in the coils, with fins stuck on. Then in the 1970's and 80's (Still R-12) the tubes became flat (elliptical, oblongular) in cross-section, exposing more r-12 to the airflow.

In R134 systems the tubes are even flatter still, and are lined with little 'turbolator" wires that force the refrigerant to spin and swirl in the tubes so that more heat transfer takes place. Dealer said 134 NEEDs this extra design to cool efficiently, and even then it doesn't do as well as r12.

So we had our Jetta evacuated, the receiver-dryer changed, and recharged with 2 lbs of freon. $320; and worth every dime; you could store popsicles in the car.

Developing business and guiding change since 1996,

G. Matthew Bulley Bulley-Hewlett Marketing & Communications Business: www.bulley-hewlett.com AIM = IExplain4u Phone: +1.919.658.1278

-----Original Message----- From: Vanagon Mailing List [mailto:vanagon@GERRY.VANAGON.COM] On Behalf Of Larry Alofs Sent: Sunday, August 11, 2002 11:27 PM To: vanagon@GERRY.VANAGON.COM Subject: Re: A/C Performance in '91 GL

Herb Harmison wrote: > > My '91 GL's A/C is not doing a great job since converting from R-12. > Because there is little information in Bentley, perhaps some of the > great people on the list can add a bit of data. > > I have a thermometer in the ducting just in front of the driver to > monitor the output air temperature. When running with all the outside > vents closed, the A/C full cold and fan speed at 3, I can get about a > 25F drop from the outside air. This means that at 85F outside I am > getting 60F air in my face. I would like to have another 10F to be > completely comfortable. > > It seems the R-12 did a better job but, lacking data, I can not be certain. > > BTW, what is ES-12? Has anyone used R-406a in a GL? > > Thanks, > > Herb Harmison > 2692 Meadow Glen Road > Ames, IA 50014 > 515-292-7059 Phone/Fax > herbh@iastate.edu

I converted my 91 to 134a. The coldest output I've measured is about 48 F. The Vanagon AC is a recirculating system. It does not use air drawn from outside. I think it is more meaningful to compare the output temp with that of the air being drawn in at the input of the unit, near the top of the back window (inside). Starting from a hot interior, I usually see about a 30 F difference, like 105 F in and 75 F out. As the interior cools down, the output temp drops, tho the differential decreases somewhat.

Another list member recently posted that ES-12 is 60% propane and 40% butane. These numbers may vary depending on whether you buy small single serving 6 oz cans or the larger (30 lb?) tanks which can handle higher pressure. ES-12 and Duracool are controversial because of the flammability. They are not legal for use in mobil AC applications by AC technicians in most states. They are apparently legal in a few states and many other countries. This issue is discussed heatedly from time to time on this list as well as other forums like Saabnet and NAXJA (Jeep Cherokees). I put ES-12 in a Saab 900 about 2 weeks ago and it works quite well. I'll probably try it in a Cherokee next week. One advantage is that it is compatible with the mineral oil used in R-12 systems, so if you don't need to open up the system to fix a leak, it is often possible to just pull a good vacuum and recharge.

Larry A.