164 AC system.

["Jose R. Castro" <amk@domain.elided>]

I have never been happy with the AC output on my 1995 164 Super. On hot
days (100+) or when the car has been out in the sun, you can barely feel
any cooling effect out of the system. I recently had the car checked by
an AC "technician" who promptly hooked up some pressure gauges to the
appropriate places on the system and declared the pressure to be too
high, i.e. the system had been overcharged by the PO. He proceeded to
release some of the gas, and guess what?-- air temperature from the AC
vents increased. He then recharged the system with new gas until he got
similar pressures as those he started off with. After this short
exercise in futility, I decided to do some research on my own. I found a
technical bulletin (No. 2022) from VACP in England (http://www.vacp.com)
where it states that checking an AC system that uses R134a for proper
charge using traditional methods does not work. That the best way to do
this is to charge the unit by weight!
In my case, I had already eliminated the following sources of the
problem: Compressor, cooling fan, drier, thermostatic switch, clogged
evaporator, dirty condenser, and AC filter. Everyone of these seems to
be operating properly. I have also run the AC computer diagnostic tests
with zero faults. Should my next step be to discharge the entire system
and recharge by weight as recommended?
Any ideas appreciated.
Jose Castro
San Salvador

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