At 01:25 PM 4/7/2005, you wrote:
>My '91 was converted to R 134 from R12 two years ago. Last year I added
>more coolant to increase the cooling ability. Now it is time for another
>re-charge and I question my procedure.

I was recently talking to my brother in law who (among other things) is an
automotive AC tech. He said that a properly functioning AC system, even an
under-charged one, shouldn't lose its cooling ability over time. He says he
laughs ads say the AC system works perfectly,  but needs a recharge,
because that means it DOESN'T work perfectly, it's LEAKING! If you need to
keep adding refrigerant, you've got a leak. If it's leaking, it's kind of
an exercise in futility to keep trying to get the system to proper
pressure, because it's not going to stay.

John Bange
'90 Vanagon "Geldsauger"