No Subject

["R. Cummings" <cumm@flash.net>]

Original Message
>Hi List!
>
>Since I bought my 5KT almost four years ago the A/C has been working
>perfectly. Now, I've read a couple of articles in car magazines telling
>that it's necessary to service the A/C system (clean the filter, check for
>leaks, add oil etc.) annually or you are risking some serious problems
>including possible damage to the compressor. I try to maintain my car
>meticulously, but, on the other hand, I have lots of bad experiences with
>various workshops and "gorillas" working there, so I don't really want to
>let them work on a perfectly working system if it's not really necessary.
>So, what should I do? The A/C blows cold. The compressor is a little bit
>noisy (a "whining" sound not very loud, but easily heard over the engine
>noise) - does this mean that there's not enough oil in the system? It has
>been like that since I bought the car. Any advice appreciated.
>
>Aleksander Mierzwa
>Warsaw, Poland
>
The only thing you need to do is make sure the refrigerant charge is not
low. I think you have a CCOT system in the 5KT so to check the refrigerant,
run the A/C on a warm or hot day in high blower, outside air (not max). With
one hand feel the small pipe going into the evaporator core after the
orifice tube and the outlet pipe going into the accumulator (the aluminum
can at the outlet of the evaporator). These should be at the same
temperature. If the accumulator is warmer than the evaporator inlet pipe the
charge is low.

If you have a TXV system then there is a receiver/dryer mounted in front of
the condenser (no accumulator). Take off the cardboard shroud between the
radiator and the front of the car and you will see it. On top of the
receiver dryer is a sight glass. Have someone turn on the A/C while you
watch the sight glass. When the compressor is engaged and disengaged,
bubbles will appear in the glass but should clear in a few seconds when the
compressor is running. Do this at a high load, outside air, max blower, hot
day. If the bubbles persist you are low on charge.

If the system is ok but has not been serviced in a few years, I add two
ounces of refrigerant oil. A little extra oil will not hurt performance but
only add a couple of ounces.

Noisy compressors can sometimes be quieted with the addition of a little oil
but if it has been doing it since the car was new it is probably ok. I have
an 83 Pontiac Trans Am with 100,000 miles and the original R4 compressor
which has been noisy for years but is still going strong.

HTH    Bob Cummings 87 Coupe GT