92 Loyale ac problem

[peterf]

Does anyone have a procedure for replacing the expansion valve on a 92
Loyale (EA82)? I'm nearly certain that this is the cause of the
over-pressure poor cooling problem. The system has been evacuated and
recharged with the correct amount of R-12 but shows very high pressure and
at idle, cycles the compressor because if the over-pressure condition. At
higher rpm or while moving, the ac functions but not very well. I think this
is a partially plugged expansion valve but not certain. It looks difficult
to remove and a procedure would really help. Thanks in advance.

 

[AS]

If the expansion valve closes, there is lower low pressure (even vacuum)
and most of the regrigerant would accumulate in the condenser and
receiver dryer without a problem. If the expansion valve opens too
much, cooling is good for a while and then freezing in the evap or
suction line occurs.

High pressure at idle makes me think of: fans not working, air in the
system, condenser clogged, excesive refrigerant. For how long and what
was the vacuum level used to evacuate the system?

Was the receiver dryer replaced? Are there crushed lines?


What is the low side pressure? What is the high pressure reading?

 

[peterf]

Well AS, you were correct indeed and thank you for the explanation. The
electric fan was disconnected. I missed it because the belt driven fan was
fine and I thought the electric was turning as well. I was doing this in the
sun during the hottest days of the season. As soon as I connected the fan
and cleared the site glass, it measured 37 degrees at the vent! WHEW!

regards,
peter