AC Troubleshooting continued...

[David Head]

Any time the system is completely depressurized the receiver-dryer should be
replaced. It holds a bag of dessicant that absorbs moisture from the system as the
freon passes through. You have the possibility of the system icing up. The system
should be evacuated and it should hold vacuum for at least an hour before adding
the freon/oil (I prefer a couple hours). If you have to replace the compressor,
you could consider going to 134 - but it won't cool as well in an R12 designed
system. The 134 molecule is smaller and you will have an increased probability of
leaks - 134 capable hoses have a plastic inside lining to reduce this, older R12
hoses don't. Also, since 134 runs at a higher pressure, all of your other
component (evap/cond/hoses) are more likely to develop leaks consistent with their
age.

Motor Sport Visions Photography wrote:

> David Head wrote:
> >
> > Sounds to me like the compressor may be shot. Is there any pressure left in
> > the system? Depress either side port fill and see. If so, jumper the lp
> > switch and try it - if the clutch picks up and the compressor make no noises
> > shut it back off and get it refilled. Most likely though ugly things will
> > happen... Alternately though you could take the belt off, put 12V to the
> > clutch and try rotating the compressor by hand.
>
> Hi Dave,
>
> Thank you for the reply. I didn't check to see if there was any pressure
> left, but that sounds like an easy check now that you reminded me.
>
> The clutch does pick up but the compressor didn't sound good. It was
> pretty rattly. However, it hasn't been the quietest for a long time (I
> think it is original and 184k miles old so if it is shot I can't
> complain).
>
> What sources do you suggest for AC parts? I assume I should replace the
> receiver/dryer (or whatever it is called) at the same time? I assume if
> there is no pressure I simple sawp the parts and take it to an AC shop
> to pull vacuum and recharge? Would this be a good time to convert to
> R-134?
>
> TIA for your help in this, you are one of the AC experts I hoped might
> chime in on this plea for help.
>
> Regards,
>
> Mike