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jimar10
09-06-2005, 07:15
Hi All,
I searched, but couldn't find a specific answer to my question. I have changed the low pressure side switch and the AC works better now. I still am not sure about the quantity of refrigerant. I currently have 1.8 lbs as specified on the little sticker. But, should I purge the system and replace with 1.6 lbs.? I have seen this recomended here, but not sure if it applies to the '01.
Thanks,
Jim
2001 C3500 Duramax

[ 09-08-2005, 10:01 AM: Message edited by: jimar10 ]
madmatt
09-09-2005, 05:30
did you charge it yourself? if so, did you completly evacuate the system w/ a vaccum pump and measure it back in?
jimar10
09-09-2005, 12:55
I had a good A/C shop evacuate it. He then put 1.8 lbs back in. He had all the proper equipment.
madmatt
09-12-2005, 12:19
did he add any oil to the system?
FleetFilter.com
09-12-2005, 17:54
My book says 31.68 ounces or 1.98 pounds.
jimar10
09-13-2005, 10:10
He added oil when he recharged it. We recharged to 1.8 lbs based on the sticker in the engine compartment. I have heard that an improvment in performance can be had in some year models by recharging with 1.6 lbs. Not sure if this applies to the '01. What book do you have?
rat4go
09-13-2005, 11:32
AC systems usually have some small amount of 'overcharge' so that the system doesn't start working lousy with any VERY SLOW loss of refrigerent that may happen at seals, fill valves, switches, etc. Going to the 'perfect' charge level to get the best performance may result in air that's a little colder, but the performance really falls off if there's any loss of refrigerant. You'd be better off adding an electric cooling fan to move air at idle (probably the condition where your AC could work better) than running a little less refrigerant.

Rich
madmatt
09-13-2005, 15:11
1.8 lbs is GM spec and I've never had a problem w/ that amount in a truck. I have seen guys add too much oil. It can have a slightly adverse affect and should be addressed if you feel this may be the problem. No more then a quater oz should be added unless some is lost during part replacement or w/ a leak. to drain any excessive oil, recover the 134, remove the accumlator and drain the amount you deem nessacary. total capacity is 8oz and about 2oz of that should be in the accumulator
jimar10
09-14-2005, 07:23
Thanks guys!