Re: [DML] A/C pressure readings - interpretation?

["David Teitelbaum" <jtrealty@xxxxxxxxxxxxx>]

Besides the problem with the hoses leaking R-12, when you convert to
-134 you have to run higher pressures. This puts more than the
designed stress on the hoses. Add to that the origional hoses are
pushing 25 years old and prudence would suggest replacement of all of
the hoses in any case. Blowing the discharge hose on R-12 is very
common anyway. As for the system pressures using -134, you will be
limited in how much you can put in because the condensor coil is
undersize for -134. You will have to keep the head pressure below the
relief valve release setting (unless you change that too). The problem
is not that -134 won't blow cold. It is that you have reduced the
maximum capacity. This means on a very hot day with the car sitting in
the hot sun it won't cool as much or as fast. On cooler days you won't
notice the reduced capacity. Kind of like an old battery. In the warm
weather it works fine. When it starts to get colder and the oil gets
thick, the cold reduces the battery's capacity, and the motor doesn't
start on the first try, you run out of power. The battery is still OK,
it still has 12 volts, but it's capacity (or storage of
chemical-electrical energy) is less than what you need under the high
load conditions.
David Teitelbaum
vin 10757


--- In dmcnews@xxxxxxxxxxxxxxx, "BRUCE BENSON" <delornut@...> wrote:
>
> I suppose I'd better knock on wood but I converted to R134 three
years ago and have experienced the coldest AC since buying the car new
25 years ago. I installed a new compressor a few years ago when the
clutch bearing failed on the old one. At that time I had the system
vacuumed and R12 re-installed. The original orifice tube was replaced
years ago because many of the original ones were contaminated right
out of the factory. I still have that replacement tube in the car.
Three years ago my son-in-law ( he owns an auto repair shop )
converted things to 134. He vacuumed the system, installed the proper o



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