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AC recharge

Discussion in 'Chevy Trucks' started by calhoun, Jul 9, 2010.

  1. calhoun

    calhoun Senior Member
    Messages: 165


    2004 2500HD 5.7 reg cab

    I didn't think my AC was bad, It always cooled, then I took a ride in the idental truck and almost got a head ache from the cold.

    I noticed at idle I have very little cooling. It was mentioned this is a sign of a low charge.

    I am told to measure presure and charge from the low pressure side.

    I have 2 valve caps on a line. Both caps are identical. This line comes from the condensor to the acumulator.
    Under one cap is a valve that looks like a tire valve. This is on the acumulator side.
    The other valve has a ball seal. This is on the condensor side.

    Which one, if any, is the low pressure?


  2. B&B

    B&B PlowSite Fanatic
    Messages: 12,777

    The port closest to the accumulator is the low side. The one upstream from there about a foot is the high side. Because the orifice tube is at the fitting connection right between them hence the high side is before the OT so of course the low side is after. Easy enough. :drinkup:

    BTW, where did you find an '04 2500HD with a 5.7......

    ....because there is no such thing. :D
  3. calhoun

    calhoun Senior Member
    Messages: 165

    Ya, I am a bit behnd the times, sometimes I still call them 350s!!!

    I guess 6.0s are not available anymore what are they now 6.1 or something.

    Thanks for the info I will attemept to charge this this weekend. If it is anything like the last time I tried, on an 89 (5.7 I believe), I will screw around with it for a few weekends then take it to the shop.
  4. haejinjoe

    haejinjoe Junior Member
    Messages: 28

    B & B is right as usual! :salute: The low side port is the smaller of the two ports and that difference will become obvious once taking the caps off of them.
    The engine in your truck is either a 5.3 or 6.0L

    Good luck with the project!


    REAPER 2000 Club Member
    from 60050
    Messages: 2,230

    NAPA carries a nice recharge kit from Sub Zero. It comes with a hose and gauge and a large can. Best stuff I believe but my mechanic says 134 is 134 and is no difference except maybe additives and he wont use em if they have a additive.