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changing freon

Discussion in 'Off Topic [BG]' started by Mike Money, Feb 28, 2006.

  1. Mike Money

    Mike Money Banned

    Mar 18, 2003
    Bakersfield California
    Avatar Speakers Endorsing Hooligan
    I told my female I'd change her freon...

    I figured I've done it in my truck... so it will be the same story in her 2000 civic, right? Ha.

    The freon tank says I need to drain the system, then add the new freon... my step dad says other wise.

    Plus, I was looking at it, and couldn't decide which valve drained it... no clear marking that I could see. It was either the big one or the small one...

  2. MurdocRocks


    Jun 18, 2005
    Torrance, CA
    I thought you needed a specialist to drain freon..
  3. See if you can track down a repair manual for the car. Libraries might have them. That should make it clear.
  4. buzzbass

    buzzbass Shoo Shoo Retarded Flu !

    Apr 23, 2003
    If you're completely draining the system, don't forget to ad a can of oil charge when you refill. The fatter of the 2 hoses is the suction side, you ALWAYS want to charge from the suction side. If you try to charge it from the high side, the can will probably explode in your hands. No Bueno
  5. Mike N

    Mike N Missing the old TB Supporting Member

    Jan 28, 2001
    Spencerport, New York
    You should really have a shop change it rather than doing it yourself. Just "draining" the old and installing the new doesn't accomplish anything.

    You need to have the system evacuated to remove any moisture that may have accumulated in it. You need a vacuum pump to do this.
  6. Trevorus


    Oct 18, 2002
    Urbana, IL
    Also, on that new of a car, it will be r-134a refridgerant. R-12 (freon) requires a license to handle. Don't just vent freon either. It's a federal offense, IIRC. R-134a doesn't have this restriction, though it's really not good to vent that stuff, either.
  7. Thor

    Thor Moderator Staff Member Gold Supporting Member

    And 2 other points to consider.

    A shop has a collection device so you don't blow the
    freon into the atmosphere. Flourocarbons degrade the

    Secondly, if it needs a charge, it because there is a LEAK.
    That will need to be checked. Often when the shop fills
    it they use freon with red dyed oil content so they can spot
    the leak.

    Also, You should use a set of pressure manifold gauges to
    introduce the freon. The pressure and (related temperature
    levels on the low side) need to be above 32 degrees.

    Too little refrigerant in the system = pressure too low, and
    if you recall Boyles Law from Chemistry, the temperature
    wil vary with the pressure. So then the system freezes.
    No good.
  8. AuG


    May 22, 2005
    Fort Collins, CO
    I'd suggest you leave this to a professional Mikey. :) Wait.....nah go ahead. You seem like the type that needs to learn the hard way. :p

  9. LajoieT

    LajoieT I won't let your shadow be my shade...

    Oct 7, 2003
    Western Massachusetts
    There is no need to drain the refrigerant. If the system is just low on pressure you just need to add more refrigerant. The only reason to drain and change it is if there is a bigger problem. If everything is working and it's just not blowing as cold as it should, a quick recharge will tell you if that's all it is. Less than $15, FAR less than any diagnostic.

    If it's an R-134 system (and I'm betting it is) it can be actually pretty easy to do it yourself. Get the chargin hose (about $10) and a can of 134 refigerant (about $3). Start the car, roll down all the windows, and crank the AC to full blast. Connect the hose to the can (follow the instructions, to be sure that the valve is turned off). Figure out which port is the LOW PRESSURE side (the hose should ONLY fit the Low side). Figure out how to connect it, but don't do it yet. First open the valve for a quick second to vent the air out of the hose (The less plain air you inject into the system the better) then connect the hose as quickly as possible. Now that it's connected, open the valve on the can and then place the can in a pan of hot water (when the can pressure drops it gets very cold, keeping it in warm water will keep it warm and help get more of the R-134A out. Now go hold your hand over the vents and feel for it to get nice and cold (if you want to get all high tech, your looking for around 50 degrees F) at which point you close the valve and remove the hose and you're all set. I've done it 3 times on my truck so far and it works like a charm, only needs it every 3-4 years.

    If it is Freon, or if you think ANYTHING might be wrong with the system other than low pressure NOT caused by a serious leak, give it to a pro.
  10. MJ5150

    MJ5150 Terrific Twister

    Apr 12, 2001
    Olympia, WA
    Maybe it's just me, but I counted FOUR points in that post. If anyone here is buying fish from Thor, you better check your bill and weigh it yourself. :D :D

  11. Trevorus


    Oct 18, 2002
    Urbana, IL
    Also, with the r-134a stuff, you can buy a charger kit that has a gauge. That is how I fill mine.
  12. Edwcdc

    Edwcdc I call shotgun!

    Jul 21, 2003
    Columbia MD USA
    You're so sexy when you talk technical.
  13. Thor

    Thor Moderator Staff Member Gold Supporting Member

    Oversold again, dang!
  14. Thor

    Thor Moderator Staff Member Gold Supporting Member

    I think your hair looks pretty sexy.
  15. LajoieT

    LajoieT I won't let your shadow be my shade...

    Oct 7, 2003
    Western Massachusetts
    Yea, I've got the whole manifold thing, and it's fine if you want to be all technical about it. But if you don't have the Temperature/Pressure chart for the refrigerant that you're using, you won't be any more accurate than the method I listed above. Also, if you turn the wrong valve, you'll open the High Pressure side into the can and potentially have a nice little R-134A bomb under you're hood.:bawl:
  16. LajoieT

    LajoieT I won't let your shadow be my shade...

    Oct 7, 2003
    Western Massachusetts
    My experience with car AC systems is they ALL leak to some extent, and will need to be recharged every 3-5 years on average. If you have a serious leak (enough to see with the UV dye) then you're going to lose pressure MUCH quicker than that. Mike said the car was a 2000, if she's had it that long and hasn't had it recharged yet, she's doing pretty well and there is no leak that they will be able to find. If she had it charged last summer, I'd have it checked. Generally if the leak is severe enough the AC will not be working at all (when the pressure drops too low the compressor stops running to protect itself). If the temperature has just not been as cold for the past year as you rememeber it, it just needs a shot.
  17. Bob Lee (QSC)

    Bob Lee (QSC) In case you missed it, I work for QSC Audio! Gold Supporting Member Commercial User

    Jul 3, 2001
    Costa Mesa, Calif.
    Technical Communications Developer, QSC Audio
    Do you see bubbles in the sight glass when the system is running, Mike?
  18. LajoieT

    LajoieT I won't let your shadow be my shade...

    Oct 7, 2003
    Western Massachusetts
    Do they put sight glass windows on cars standard these days? Every one I've seen was put on afterwards.

    I haven't had a vehicle newer than '95, so none that I've had have ever had one. That would make life easy, but I just don't see most car makers doing that.
  19. Mike N

    Mike N Missing the old TB Supporting Member

    Jan 28, 2001
    Spencerport, New York
    Imports and Chryslers are the ones I see with sight glasses.
  20. make sure she runs the air every couple weeks, even in the winter. Keeps the seals lubricated, prevents leaks.

    If she's got a Honda, its likely the defroster kicks the AC on automatically, and this wouldn't be an issue, just use the defroster on cold days (if you have winter) once in a while.