Date: Sat, 02 Jul 2005 07:05:47 GMT From: "James Sweet" <jamessweetnospamail.com> Subject: Re: Re: Re: A/c compressor 1999 9-3
> > perhaps I exaggerated when I said pump down for hours but as noted, the > vacuum is never too good and 30"Hg. is adequate. If you can attain more, > so much the better. > Technically 30 in/Hg is a perfect vacuum, but in reality an ordinary vacuum guage is not nearly precise enough to measure the last remaining bits, but in this case it's not critical anyway. > > If the receiver dryer is one combined unit, It does no harm to leave it > in place and simply add a generic filter/dryer. > That's not nessesarily true, the saturated silica gel expands and the pouch that holds it can burst. It happens and when it does it's a BIG mess and will normally destroy the compressor. I don't know what the 9-3 uses but usually the filter/dryer is easily accessible for replacement. > > After replacing the compressor, which is almost always the case, always > add a filter. A new filter. The failing of failed compressor creates a > lot of crud that you do not need fouling the replacement. I have seen > sticklers who after a week or so will remove and reinstall another > filter dryer pump down and recharge. This may be a "belt and suspenders" > approach, but those who did it had plenty of automotive cooling > experience. > That's probably a little excessive, though a really bad failure may make it worthwhile. Normally this is only an issue in central A/C or heat pump systems where a compressor burnout results in lots of nasty acidic gunk in the hermetic system from the varnish burning off the motor windings. It's not particularly easy to flush out one of these systems so they make special cleanup filters to be installed after such an incident.
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