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RE: a/c compressor (Pt. 2)
I got out there and jumped the low-pressure cutoff, and sho' 'nuff, it came
on. I grabbed the low-pressure line and felt no real coolness. I grabbed
that gauge thingie with the blue and red areas to mark the low and high
pressure R-12 zones, and noted that both sides, while different from one
another, were either at or below the low pressure blue area on the gauge. I
waited 30 minutes with the engine off, as the instructions I found under the
gauge ( and under the instructions for my torque wrench -- guess I shoulda
looked harder the first time!) suggested, and noted that the measurements
equalized.
I grabbed Can #1, and commenced ta fillin.' Frustrating thing, this; I never
did get the feeling I was doing it right, either this time or the last time
(years back) I tried it. The can gets all cold, but I can't perceive a drop
in weight in the can. After what seemed an interminable amount of time, I
closed the can valve, removed the feeder tube, and reconnected the gauge (I
had begun to see bubbles in the sight glass already). Sure enough, the low
side read in the normal range, and the high side was about 3/4 of the way to
where the gauge face wanted it to be (about 150, I think). Inside, the air
didn't feel much cooler, but it never really felt super-cool before anyway. I
stopped here, not wanting to emit good Freon after bad, and came in to compose
this.
If the can ices over when I'm dispensing, am I doing it right, or is that no
indicator one way or the other?
How long does it typically take to discharge one completely? I held it
upright as the charge kit instructed; is that valid?
Given that the system still had some residual pressure, I theorize (why I feel
qualified to theorize after a few helpful e-mails and some 10-year old
instructions fished from the bottom of a toolbox I'll never know; I must be
some kinda Idiot or sumpin' :)) that perhaps I just have leaky old seals that
finally gave way for our first cold snap (48 degrees was cold to US!).
If so, are those cans of lubricant/sealant still available, even though the
R-12 is gone? Turns out I have three cans (well, 2-1/2 now) left. Rick, if I
can get through this with one can intact, it's yours, man.
----------
From: Rick Lackner
Sent: Monday, October 06, 1997 3:04 PM
To: Jeff Wheeler
Cc: scirocco-l@privatei.com
Subject: RE: Re[2]: a/c compressor
> I gather that what I'd be looking for in this test would be to see if the
> pressure sender, keeping the clutch from engaging to avoid the damage that
> Shawn noted, could be overridden to get the clutch to "catch," right?
Yes, you only want to override the switch to see if the compressor
engages, and to look in the sight glass to see if there are bubbles
which means the freon is low. After the compressor is engaged for a
bit you can feel the hoses to get an idea of what's going on also.
The hose leading from the evaporator (inside the passenger
compartment) to the compressor, or "low side" hose, should get cold.
The "high side" hose from the compressor to the condenser should get
hot. These are quick checks that can help give a quick idea if it's
at least semi functional.
The "feel" test, other than having gauges on both the low and high
side to observe pressures, is the best diagnostic toll you can use.
The hose from the compressor to the condenser should get really hot,
the hose from the condenser to the dryer a little less hot, same for
the one form the dryer to the expansion valve. The other side of the
expansion valve should be cold as hell, the hose from the evaporator
to the compressor a bit less cold, as the cold should have been blown
into your passenger compartment. The whole thing is based on
pressures and compressing and expanding the gas.....it's kinda neat
when you get into it.
> I've still got a couple of cans of Freon lying around from Back When We
Didn't
> Know Any Better, and the recharge kit that included that swell gauge. Seems
I
> recall that the compressor had to be compressing for the gauge to read
> anything meaningful (of COURSE I lost the instructions; sheesh); does anyone
> else recall the same thing? Supposing it did spring a leak; how many cans
> would it take to get it back up to snuff?
I couldn't find capacities for the a/c in Bentley, it only says never
add more than 3 cans. Somehow I seem to remember reading somewhere
the capacity is about 2 to 2 1/2 lbs. Sometimes you'll find a label
on the compressor telling you the system capacity. The best way to
know when it's full is to watch the sight glass located on the top of
the receiver/dryer which is underneath the windshield washer resevoir
(sp?). You fill it until the sight glass bubbles disappear. A
little note, let the compressor cycle a few extra times to be
sure all the bubbles are gone, and then give it just a a little
extra shot of freon to account for the loss you'll have when
removing the fill hose and gauge. Yes, it will only give meaningful
readings while the compressor is running and will only suck in freon
while engaged.
BIG ASS DISCLAIMER..........If you're not 100% sure you can tell the
low side hoses and gauge hook-ups from the high side, DON'T F**K WITH
IT!!!!! Serious bodily harm can and will occur if you try to hook
the gauge and cans up to the high side.
> Wouldn't be so big a deal if I didn't live in Columbia, SC, home of the
Sweaty
> Christmas.
Awww, quit yer bitchin :)
BTW, how many cans of freon do you have sitting around? I could
really use one to top off my system....hint, hint :) Would gladly
overpay for one of these little beauties *grin*
If you have any more questions. I'll be glad to try and help. I used
to do a/c work in a garage in a former life.
Hope this is of some help......of course if the compressor doesn't
engage then you have an electrical (relay?) problem......which would
be cheaper to fix anyway, and less dangerous. Check the grounds from
the compressor, mine was disconnected and preventing mine from
working.
If the problem is low (or worse no) freon, you had a massive leak and
it may be costly if it's a major component. Keep the fingers crossed
for electrical probs :)
Rick
hugacub@whidbey.net
Richard.Lackner@entex.com
85 Scirocco 8V Wolfsburg
Everett, WA
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