- Alfa Repair & Restore Tips Forum -
Spider Series III -- Air Conditioning Servicing

Bill Unger
registered 2008-10-12
Florida Alfa Club *

All References to ARM = “Alfa Romeo Workshop Manual - Spider” Publication PA 3748

Air Conditioning System (ARM 80-33)

You will need to invest in an inexpensive A/C Manifold Gauge Set from Harbor Freight,Northern Tools, etc. to do this.

Performance Test:
1. Close (clockwise screw in) red and blue manifold gauge set valves. Close (counterclockwise screw out) red and blue control valves and connect to one end of corresponding hoses. Use PAG lubricant on rubber O-ring inside valves if it is difficult to seat.
3. Yellow Hose -- Connect both ends of hose to gauge set.
4. Red High Hose -- Connect one end to bottom of gauge set; connect other end with red high pressure coupler to high pressure valve (red cap “D” top of compressor) on vehicle.
5. Blue Low Hose -- Connect one end to bottom of gauge set; connect other end with blue low pressure coupler and extension/conversion hose to low pressure valve (blue cap “S” top of compressor) on vehicle.
6. Open (clockwise screw in) blue and red control valves (not the gauges) on hoses.
7. Start vehicle, open windows, turn on A/C to full cold and let gauges stabilize (about 10-15 minutes).
8. Obtain low and high pressures by reading innermost black band on gauges.
(NOTE: >0=psi low pressure side, <0=inHg vacuum equipment. Ignore all other bands.)
9. Compare to the following chart to determine if readings are within Normal range:

Ambient Temp (°F) Blue LowSide Gauge (psi) Red High Side Gauge (psi)
65° 25 - 35 135 - 155
70° 35 - 40 145 - 160
75° 35 - 45 150 - 170
80° 40 - 50 175 - 210
85° 45 - 55 225 - 250
90° 45 - 55 250 - 270
95° 50 - 55 275 - 300
100° 50 - 55 315 - 325
105° 50 - 55 330 - 335
110° 50 - 55 340 - 345

System Pressure Fault Diagnosis:
Low Side High Side Discharge Air Fault Cause
normal normal initially cool then warms moisture in system
low normal initially cool then warms moisture in system
low low slightly cool or warm refrigerant charge low
low low sl cool or frost@exp valve expansion valve stuck clos
low low sl cool,sweat,frost@restrict restriction in High Side
high high warm, high side pipes hot refrigerant charge high
high high warm, high side pipes hot inefficient condensor coil
high high warm, sweat,frost@evaporator expansion valve stuck open
high low compressor noisy(needle vib's) defective reed valve


Recharge:
10. Yellow Hose -- Connect one end to bottom of gauge set; connect other end to R134a tank.
11. Invert R134a tank and open tank valve.
12. Open (counterclockwise screw out) blue manifold gauge valve. Coolant will begin to flow from tank through gauge set (visible in sight glass) and into vehicle through low pressure valve. The low pressure gauge will increase.
13. When air from A/C gets cold, close blue manifold gauge valve. Allow system to stabilize and reread low and high pressure gauges. Compare to the preceeding chart to determine if readings are within Normal range.
14. If Low, then continue charging by repeating Steps 12.-13.
15. If High, then close (counterclockwise screw out) blue control valves and disconnect blue hose coupler from vehicle. Bleed pressure from vehicle system, reconnect blue hose, and recheck pressures.
16. If Normal, then close (counterclockwise screw out) red and blue control valves and disconnect couplers from vehicle. Close R134a tank valve and disconnect yellow hose from tank.

Capacities (ARM 80-34):
Total system capacity old R-12 -- 1.54-1.76 lb
Total system capacity R-134a -- R-12/1.15 (R-134a is 15% lighter than R-12)
= 1.34-1.53 lb = 21-24 oz
Lubrication -- 3.5 oz PAG46 per lb of R-134a = 4.7-5.4 oz
Since the compressor holds 70% of the lubricant (ARM 80-28,32), add 3.3-3.8 oz PAG46 and the balance 1.4-1.6 oz PAG46 to the drier-accumulator.

Bill Unger, 1987 Spider Veloce




* Note: the club listed under a poster's name is optionally set by the user in his/her registration profile; it is not a confirmation of club membership.