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AC pressure after changing compressor ????????

Discussion in 'General Chevy & GM Tech Questions' started by DAREDEVIL, Aug 16, 2010.


    DAREDEVIL Rockstar 4 Years 1000 Posts

    Hi, i need to know how much pressure i need to fill in my 1996 Suburban !

    It has rear AC aswell.

    Any help would be very much apriciated .


    PS, maybe somebody knows how much goes in a 88 Camaro also ???? LOL ( wifes car )
  2. MightyMax

    MightyMax Rockstar 100 Posts

    Did you add in oil to the COmpressor as well??

    And put a vaccuum on the system??

    If those are in place, it should take about 3 - 4 cans easily.

    Do it with manifold guages, then you can watch the pressure build, and stop when it gets to 40 - 45 Low side.

    I don't believe the fact of having rear air makes a difference, but I could be very wrong on that assumption.

    ---------- Post added at 11:21 PM ---------- Previous post was at 11:19 PM ----------

    If you put on a new compressor and therefore the system is empty.

    If not done as well, change out the accumulator and the orifice tube.
  3. murdog94

    murdog94 Epic Member 5+ Years 5000 Posts

    X2... And yes 40 -45 MAX PSI depending on temp, which most of the R134a cans have a temp guide, on what the proper charge is for the ambient temp.

    DAREDEVIL Rockstar 4 Years 1000 Posts

    Thank u all, but i have a 30# can and REAL gauges to fill the AC , also yes...oil in and vaccum done..-28 !!!!
    but @ 45 PSI my compressor wont even turn 65 it will work fine...??????????????????????????mmmmhhh
  5. murdog94

    murdog94 Epic Member 5+ Years 5000 Posts

    Seems that your high pressure switch has had it. And you are at 45PSI on the low side with the compressor running? not to be stupid just confused because i know that real guages allow for more accuracy. but you should have a 3lb system. So i would have installed 3lbs and gone from there. but that is why i am confused because your low side should be 45lb with the compressor engaged. If the compressor is off then it isnt sucking on the low pressure site to lower the system pressure.

    DAREDEVIL Rockstar 4 Years 1000 Posts

    When the compressor is running it reads 55-60 PSI on low and about 250 on high !!!!after turning it off, it reads 75 on both !!! mmmmmhhhhh I'M LOST ..LOL

    Tomorrow i will bring it to an AC shop and let them figure this SH[T out..hahaha

    98 degree down here today ....sweting my a$$ off.
  7. murdog94

    murdog94 Epic Member 5+ Years 5000 Posts

    Hmm sorry man. Confussed is right.. Is it cold at least?? And do you know how many lbs of R134a you put in? But it really seems like you have a bad high pressure switch. And or else a low pressure switch depending on which you are jumping to get the compressor to run...

    DAREDEVIL Rockstar 4 Years 1000 Posts

    Not jumping any...just filling it untill ~ 60 and then it comes on !!!!! and yes its cold but i still have a small leak in my thats why i filled it new ( i thought i fixed the leak ) THOUGHT !!!!!! is the main I found out that J&B weld is not strong enough on aluminum AC pipes...hehehe
  9. murdog94

    murdog94 Epic Member 5+ Years 5000 Posts

    WEll thanks for the insight.. and that may be some of your issue is a the leak may not be allowing the proper pressure at the actual switches.. But i would lean twards a bad low pressur switch then. Since it is supposed to tell the compressor to kick on when you obviously have enough pressure.

    DAREDEVIL Rockstar 4 Years 1000 Posts

    THANKS, i look into it !!!!

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