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ScottG's avatar
ScottG
Nomad
Jun 17, 2018

Recharging vehicle AC Q

After 16 years, last year My AC started showing the classic signs of low charge (and for some reason it didn't get better over the winter...) so today I hooked up the gauges and charged it from a bulk R134 tank.
I got both the high and low pressures in spec but the high was just barely. It didn't seem like adding more R134 was going to do anything but raise the low pressure side but I could be wrong.

Question of those knowledgeable with these things; Was I not able to get the high side higher because the system needs to be put under a vacuum or rather, evacuated and recharged?

Everything is working fine and in-spec but I wonder if it could be better.

Thanks in advance,
Scott
Tow Vehicles
  • ScottG's avatar
    ScottG
    Nomad
    Jun 18, 2018
    colliehauler wrote:
    You need to monitor the high pressure side as well. If it is to high the system is plugged and will blow the seals out of the compressor. Most self recharge kits only tell you the low side pressure.


    I was all set to use one of those kits and after a lot more research, decided against it.
    I can see using just the low side if your lucky and nothing else is going on. If your not lucky you just destroyed some expensive stuff. Since a set of gauges is only $30~$60, it doesn't make sense to me to cut corners.
  • colliehauler's avatar
    colliehauler
    Explorer III
    Jun 18, 2018
    You need to monitor the high pressure side as well. If it is to high the system is plugged and will blow the seals out of the compressor. Most self recharge kits only tell you the low side pressure.
  • ScottG's avatar
    ScottG
    Nomad
    Jun 18, 2018
    Beware of using temperature charts found on the web as they are generic at best.
    I have found that specific FSM values for a given vehicle (like my Dodge) can be VERY different from those generic things. That could result in poor performance or damage.
  • colliehauler's avatar
    colliehauler
    Explorer III
    Jun 18, 2018
    Just got through replacing the fan clutch, compressor, drier, hoses, and condenser on my 06 Ford. My mechanic recommend discount A/C parts for the best price. They will not warranty a new compressor unless you replace the condenser and drier. There design prevents them from being flushed of any contaminates.

    My system had all kinds of contaminates from the condenser failing.
  • colliehauler's avatar
    colliehauler
    Explorer III
    Jun 18, 2018
    turbojimmy wrote:
    MegaCab_PL wrote:
    I am watching this thread as I am facing similar issues on my 06 Explorer. I am not loosing the charge since it's blowing somewhat cold air. I tried to recharge it using those small tanks, but that did not help much. What should be the vent temperature when my settings are down to 60 F ?


    They key is to charge it while keeping the low side pressure in manufacturer specs. The pressure is dependent upon ambient temps - I'm sure you can google to find the specs. Ideally you'd also want to keep an eye on the outlet temps as you charge it, too. If you overcharge it outlet temps will actually start to warm up.
    Correct you have a certain capacity of the system undercharge or overcharge it will not work correctly. A lot of the time the problem is the fan clutch on the engine is shot not bringing enough air through to work properly.
  • turbojimmy's avatar
    turbojimmy
    Explorer
    Jun 18, 2018
    MegaCab_PL wrote:
    I am watching this thread as I am facing similar issues on my 06 Explorer. I am not loosing the charge since it's blowing somewhat cold air. I tried to recharge it using those small tanks, but that did not help much. What should be the vent temperature when my settings are down to 60 F ?


    They key is to charge it while keeping the low side pressure in manufacturer specs. The pressure is dependent upon ambient temps - I'm sure you can google to find the specs. Ideally you'd also want to keep an eye on the outlet temps as you charge it, too. If you overcharge it outlet temps will actually start to warm up.
  • MegaCab_PL's avatar
    MegaCab_PL
    Explorer
    Jun 18, 2018
    I am watching this thread as I am facing similar issues on my 06 Explorer. I am not loosing the charge since it's blowing somewhat cold air. I tried to recharge it using those small tanks, but that did not help much. What should be the vent temperature when my settings are down to 60 F ?
  • turbojimmy's avatar
    turbojimmy
    Explorer
    Jun 17, 2018
    I wouldn't worry about it with those outlet temps. You only need to vacuum it down if the system has been opened up.
  • ScottG's avatar
    ScottG
    Nomad
    Jun 17, 2018
    newman fulltimer wrote:


    On a bulk tank did u flip the tank upside down to fill as suppose to do


    Well of course I did, or at least I did when I tried to purge the charge line with the tank in the wrong position and then remembered I had to turn it over. :B

    I'm probably concerned about nothing. The outside temp was 77~79 degrees and all the vents were blowing at 40~41 degrees.

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