Keith
Looks like the Keith's are in agreement here. Although I am not certain 
of a high pressure AC switch on my 84. No doubt the relays are set to 
give priority to the high speed fan at the expense of the AC 
compressor. Meant to be that way, it seems. I don't think anything 
abnormal is happening with the radiator: no discolored fluid, no leaks, 
apparently good circulation, resent/frequent coolant change (VW 
approved) and normal operation for 10 years. Just looks to me like the 
old 84 has trouble running the AC at temps in the triple digits. Or am 
I still missing something?

Keith O

On Jul 19, 2005, at 9:51 AM, Keith Hughes wrote:

>> Date:    Tue, 19 Jul 2005 07:15:37 -0400
>> From:    Edward Maglott <emaglott@BUNCOMBE.MAIN.NC.US>
>> Subject: Re: AC converted to 134
>>
>> I was not aware of a system that turns off the compressor when engine 
>> temp
>> reaches a certain level.  I thought it was just based on pressure 
>> within
>> the AC system.  It turns the radiator fan up to high, and if it still 
>> can't
>> lower the pressure the compressor will turn off until pressure drops 
>> below
>> preset level.
>> Edward
>>
>>
> At least from '86 onward, the second setpoint on the two-stage radiator
> fan thermoswitch (102�C / 216�F) does two things: Turns off the A/C
> compressor, and turns the Rad. Fan on High.  The only thing the high
> pressure (freon pressure) switch does is to kick the radiator fan up 
> the
> the intermediate speed on high discharge pressure - it will not shut
> down the compressor.  So...anytime the rad fan kicks into high, the
> compressor shuts down.
>
> Keith Hughes
>