1994 del sol Si manual
175,000
system leak found at high side tube and replaced
replaced compressor and drier at same time (AC used to only cool at higher RPM, not at idle)
28.5" Hg for 2 hours; added 134A (~18 oz)

Clutch comes on when pressing AC button

At ambient temp of 80 deg F and engine off: low and high @ 95 psi
engine at idle (800 rpm) and clutch on: 25 psi low, 170 psi hi
5 minutes after engine turned off, 50 psi low, 130 psi hi
it takes over an hour for the the pressures to equilibrate to 95 psi

center vent temp drops from 80 degF to 70 deg F

The clutch is not cycling on and off, it comes on and stays on.

High side tube gets very hot to touch; low side is cool but not cold and no condensation.

What else should I be checking?

 

 

Thanks for the info Ron.

A friend suggested that I increase the RPM to 3000 RPM.

idle: 20 psi low/ 170 psi high
3000 rpm: 12 psi low/ 270 psi high


Incidentally, the vent temp dropped from 70F to 55F when increasing RPM.

Creating a vacuum on the low side and increasing pressure on the high side
indicate a restriction according to my friend. Most likely candidates are condenser, evaporator or expansion valve.

Splashing water on condenser did not effect high side pressure. My friend
suggests that this means the condenser is not where the restriction is. Best
guess is either expansion valve and/or evaporator.

 

Service manual says to use 1500 rpm.