"Greg O" wrote in message
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"Bill Noble" wrote in message
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"Lloyd E. Sponenburgh" lloydspinsidemindspring.com wrote in message
.70...

interesting stuff snipped ----------

Quick answer -- no... you can't tell with mechanical gauges.

LLoyd

interesting post - I wonder if where you live matters

I have repaired a number of cars where the AC system is empty - mostly
944s in fact - swap the seal on the pump put in some of the new oil for
R134, and fill - works fine. on one that exploded a hose in 130 deg
weather, just replaced the hose (a few weeks later), and it worked fine.
Never saw any moisture effects. So, why does your experience differ?
could it be a drier climate, or could it be something else? Note, I am
not questioning your advice/report, it makes perfect sense, I'm wondering
why I can get away with not doing all that stuff?

Possibly the systems you worked on were clear of moisture before you
opened them, and you had them open for just a short time, so the amount of
moisture in the system was minimal.


useful story snipped

In my particular case, at least one of these cars was open for several weeks
while I sent the compressor out for repair, the one with the exploded hose
was open for at least a week. I think the drier climate, and the fact that
I wasn't operating the compressor with the system open might explain some of
it - still, the very different results surprises me. I have pulled a vac
(no, I don't have one of the "good" gauges) and just let the pump run
overnight on one system - I didn't notice any improvement, but it wasn't
worse either, compared to the ones that didn't get this treatment.

On my 59 cad, the car was empty of freeon for probably 30 years - I added
freon and it worked (but leaked down after a year or so, I haven't recharged
it in a long time) - but it was stored (in very poor shape) near Oildale - a
very very dry area.

I wonder - maybe the careful treatment for moisture applies only when the
humidity is above 5%? 10%?