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Date:         Wed, 20 Jul 2005 10:55:46 -0700
Reply-To:     Keith Hughes <keithahughes@QWEST.NET>
Sender:       Vanagon Mailing List <vanagon@gerry.vanagon.com>
From:         Keith Hughes <keithahughes@QWEST.NET>
Subject:      Re: AC converted to 134
Content-Type: text/plain; charset=ISO-8859-1; format=flowed

Keith Ovregaard wrote:

>>Keith H and all who have responded... >> >>I know this is a bit long-winded, but it sure would be great to find the >>best solution to making the AC work properly. >> >>I live near San Francisco in Larkspur and even though we do have a few >>100+ days. the norm is more like mid 80's and the 84 Westy does not get >>exposed to much extreme heat. Also the AC has been out for a few years >>(although it cooled OK, just barely, in the past using the old R12 on a >>90° day). I get the feeling that the 134 conversion I did was not a >>great idea and has been a very expensive lesson in AC technology. >> Unfortunately, R134A really is a bad idea in a vanagon, IMO, and especially in a pre '86 with the smaller condenser. If you want to stick with R134A, and want cold A/C at 100+°F ambient temps, you're likely looking at:

1. Increase condenser capacity - R134A requires more capacity than R12, and the Vanagon's undersized for R12. Either install a larger and/or more efficient condenser, or add a second condenser/fan under the van downstream of the existing condenser. I had a '78 Westy with this configuration (minus the front consenser of course), with a dual fan/shroud setup. Worked better by far than my '86 Westy does (with about half the condenser capacity).

2. Replace the expansion valve with one designed for R134A. They *are* different.

3. If your problem is only at slow speeds or at idle, upgrading to the '86 and up fan/shroud combo will help both A/C cooling and engine cooling performance. If you have the same issues at highway speeds, upgrading the fan/shroud will do nothing for you. If A/C and engine can't stay cool with 60mph airflow, you have other problems.

>>I have >>also found some info on several 134/R12 alternatives (Duracool, >>Maxifridge) from listers and local mechanics. Maxifridge states on its >>website the following: >>"Enviro-Safe Refrigerants are hydrocarbon refrigerants that are >>ultra-efficient . >> >> *All* hydrocarbon based refrigerants are illegal for R-12 replacement (see http://www.epa.gov/ozone/snap/refrigerants/lists/unaccept.html). Whether this applies to an R-12 system that has been converted to R134A is another matter, and many shops will likely err on the safe side.

>>6 oz. of Enviro-Safe is equivalent to 18 oz. of R-12 or 16 oz. of R-134a. >>12 can/cases of ES-12a can be ordered for only $59.00" >>That's cheap! The R12 here has been going for $75-80/lb and 134 is not >>so cheap either. >>

If you use one of these 'bastard' products, you just need to realize that you will almost certainly have to do the servicing of it yourself. A licenced shop has to have recovery equipment dedicated to your specific product in order to drain it and repair it. So, repair options will be limited 'cause not many will purchase the equipment for the limited business available.

As for R12, get EPA Section 609 certified (do it online here http://www.imaca.org/training.htm for $15) and buy off of Ebay, or online vendors, for $20-25 for a 12-oz can. Take your freon with you, and let them charge you labor for installing it. They won't like it, but you can easily find someone who'll do it and still save you $$$,

>>Has anyone tried the alternative stuff? >> >>

I've used Freeze-12 and it seems to work well. Another issue with these mixtures is dissimilar leak rates for the various components. The mixtures with R22 need barrier hoses installed, and even then the R22 will leak faster. So, when you recharge, unless you drain and evacuate the system, the mixture changes, affecting the cooling capacity, and possibly the oil-carrying capacity as well which doesn't bode well for the compressor. Just some ramifications to think about.

>>I wonder if the compressor does not have to work so hard using something >>besides 134, maybe it won't shut down when it gets so hot. >> >>

Well, the compressor will like anything that gives it lower high-side pressures. R134A is about the worst in that category. But it won't make any difference as far as shutting down on high temp. That's a cooling problem (water cooling). In fact, if you install a larger, or more efficient, condenser up front the van *will run hotter*, since the air reaching the radiator will be hotter than it is now. It has to be to provide additional freon condensation. Installing a second condenser/fan unit will help the A/C cooling, without more engine heating, but the compressor will still kick out as much as it does now.

I 'll bet that if you pull the radiator out you'll find that it's clogged up, and causing your overheating problems. If you overheat (and the high speed fan coming on when you're not doing a lot of stop and go in *hot* weather is my definition of overheating here) with the A/C and not without it, that's a good sign of real marginal cooling. The additional heat load (to the radiator) caused by the A/C condenser pushes over the edge. Hopefully, your heads and case aren't too scaled up to cool properly (like mine was), and a good pump and radiator will take care of the overheating. Once that's fixed, see if the A/C will perform OK when the compressor isn't kicking in and out - because the compressor cycling will make it impossible to cool.

Keith Hughes


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