Automotive Air Conditioning Information Forum (Archives)

jgcox6 on Tue April 12, 2011 9:04 AM

Year: 1995
Make: Saturn
Model: SC2
Engine Size: 1.9l
Refrigerant Type: 134A
Country of Origin: United States

I have a couple questions concerning expansion valves. What are the symptoms of a bad or border line expansion valve. I do know that when one is stuck closed that you can have "vacuum" on your gauges. Would an expansion valve partially work...not allowing the air to get very cool.

I just completed replacing the drier and some orings in the system, adding oil amount that I got out of the old drier, and then vacuuming down the system four or five times with no leaks. I then recharged the system with 24oz of 134a. I charged based on the Saturn bay recommendations (engine 2000 rpm) and all seems well with a vent temp of 45deg with an ambient temp of 72 deg. Low and high readings seem withing Saturn's specs...but when in the car with ambient temp of 80deg, seems to not be cold enough. Is that indicative of a faulty expansion valve? Not very familiar with expansion valve systems. Is it worth my will to replace the expansion valve. The compressor seems to be strong enough to give me high side pressures within specs.

I read one of the threads about possibly having to "overcharge" the system first on the rotary vane type compressor..should I add about another quarter of a can of 134?

TRB on Tue April 12, 2011 9:13 AM

What are your pressure readings at idle and 1500 RPM?

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jgcox6 on Tue April 12, 2011 8:28 PM

the low side reads about 25-29 and the high side with a 2000rpm per the saturn manual, is about 150....seems ok to me..but just wondering if I should add a bit more 134. It seems that the compressor is doing it's thing right. I just am not comfortable with the expansion valve.

TRB on Wed April 13, 2011 2:06 PM

Connect manifold gauge set. Install thermometer in right center vent. Open doors and windows. Depress recirculate button. Set temperature lever to full cold position. Set blower speed to III. Depress A/C button and run engine for 3-5 minutes at 2000 RPM. Compare readings to A/C SYSTEM PERFORMANCE TEMPERATURE SPECIFICATIONS (IN SERVICE BAY) table and A/C SYSTEM PERFORMANCE PRESSURE SPECIFICATIONS (IN SERVICE BAY) table.

A/C SYSTEM PERFORMANCE TEMPERATURE SPECIFICATIONS (IN SERVICE BAY)
Ambient Temp. °F (°C) (1) Outlet Vent Temp. °F (°C)
70 (21) 40-48 (4.4-8.8)
80 (27) 42-49 (5.5-9.4)
90 (32) 43-50 (6.1-10)
100 (38) 50-56 (10-13)
(1) Measured at right center air outlet.



A/C SYSTEM PERFORMANCE PRESSURE SPECIFICATIONS (IN SERVICE BAY)
Ambient High Side Low Side
Temp. °F (°C) psi (kg/cm2 ) psi (kg/cm2 )
70 (21) 115-170 (8.0-11.9) 28-30 (1.8-2.1)
80 (27) 180-215 (12.6-15.1) 23-28 (1.6-1.9)
90 (32) 225-270 (15.8-18.9) 22-27 (1.5-1.8)
100 (38) 275-320 (19.3-22.4) 23-27 (1.6-1.8)




-------------------------

When considering your next auto A/C purchase, please consider the site that supports you: ACkits.com
Contact: ACKits.com

JoshuaSulwer on Sun August 09, 2015 3:28 PM

So what do we know about expansion valve testing to know if they are bad?

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Thank you