Engine Size: 3.0 Litr
Refrigerant Type: R134a
Ambient Temp: 95F
Pressure Low: 35-41
Pressure High: 270-290
Country of Origin: United States
New compressor,receiver/dryer, and expansion valve. Flushed and back flushed all lines(no mufflers on lines), evaporator, and condenser thoroughly. Evacuated system for 1 1/2 hours. Charged system with R134(36oz.) and temperature at center vent dropped to 40 degrees fahrenheit at idle. Outdoor temperature was 85 degrees fahrenheit. Low side gauge at 33psi, high side gauge 182psi. Drove for about 20 minutes and temperature never dropped more than 40 degrees fahrenheit. From time to time I here a scretching sound like the compressor may be trying to lock up or belt is sliping (new belt) Sound last 1-3 seconds and stops. Happens about every 20-30 minutes. Gauge readings with ac off are Low Side:88 psi and High Side: 92psi. When ac is on readings are Low Side: 35-41psi and High Side is 270-290. Temperature at center vent is now 50 degrees fahrenheit. Outdoor temperature was 85 degrees fahrenheit
Edited: Sun May 30, 2010 at 11:46 PM by HarvO
Check the radiator cooling fans, does this have rear a/c also?
Radiator fans work fine and Caravan does not have rear air.
I list 9 ounces of oil and 34 ounces of R134a for a front only system.
System Operating Pressures 70 degrees ambient.
High Side112-210 psi
Low Side10-37 psi
Thank you for your help on my ac problem. According to my Haynes tech book (which is all I have to go by) the oil capacity on a front only unit is 5oz. and 7.5 oz. with rear air. R134a is 2.14 pounds which is pretty much 34oz. Could moisture in the system cause my high readings? I evacuated system for hour and a half but it was a very humid day. Thanks again.
It's strange that it worked fully to spec when you first started it up (who would complain about 40F at idle), then something went bad. Clearly the charge amount did not increase. So are you sure the fans work all the time?
I know that I only have 5oz. of oil in system. Could being 4oz. short cause my high readings?
It could cause the compressor to start to lock up as described. Increasing you pressure I donÃ¢ÂÂt think being short would have that effect in the short term. I still think along the lines of MK378 that you may have an air flow issue. But you should get the correct amount of oil in the system before you burn up the compressor.
Should I add oil thru a charged can and service hose or should I pour it into one of the components? If I open the system to pour in oil do I need to replace receiver/dryer
You donÃ¢ÂÂt want to add anymore refrigerant. So I would reclaim and add the oil through a component. Drier change would not be needed.
Thank you for the advice.
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