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How Do I Recharge My Ac

Discussion in 'Minivans · Pacifica' started by greg.owen, Jul 27, 2003.

  1. knudln

    knudln New Member

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    The little orange light in the A/C button lights up. I gave it another try, but I squirt a little Freon in (guage went up to 45lbs.), an it just sits there at 45lbs. It's as if all I'm charging is the 12" of hose that goes to the low pressure line. I left it sitting like that for five minutes, and no change on the pressure guage. When I disconnect the freon can and try again, the guage starts out at 0lbs. I realize now that the needle on the guage starts out at about 5-10lbs., so I'm assuming that this is actually 0lbs. The A/C button is on (lit up) and the front and rear fans are on high. Compressor still isn't spinning. Any ideas?
     
  2. NYBo

    Level III Supporter

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    Check the connector on your fill kit. It sounds like it's not opening the fill port, which acts just like a tire valve. Are you sure you're getting it fully connected?
     
  3. superk13

    superk13 Guest

    I too have one of these wonderful 96 caravans with less than the best AC. The problem with my is that at idle the ac is really not that cold. On the open road it will get cooler for a while, or at least it seems like it, than changes back to warm. On a really hot day it is impossible to cool the inside of the vehicle. I have replaced the compressor and both evaporators front and rear. Does anyone have any idea why it cycles from cool to warm?
    Thanks
     
  4. Berretta

    Berretta Guest

    I have a 93 D grand caravan 3.3l V6

    the a/c is holding 35psi but it just takes forever to get cold. will purging air from low side help. or will it evacuate refrig. (its a 134a system).
     
  5. DodgeG

    DodgeG Member

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    Superk13,
    Check your radiator fan, at idle when you turn on AC, it should be spinning high.
     
  6. NYBo

    Level III Supporter

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    Do NOT try to purge air from the system! The a/c system isn't like the cooling system where air will rise to the highest point of the system.

    35 PSI is a reasonable low-side pressure when the system is in operation. But you need to know the high-side pressure. Also, try the reset/recalibration test here:
    http://www.allpar.com/fix/codes-climate.html
     
  7. Police Interceptor

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    I have a question about A/C in my 97'. I just changed the evaporator in it as well as new drier and o-rings. I will be vacuuming the system and filling it with R-134a. I need to know the low and high side pressures. Is it 45 psi and 300 psi?
     
  8. NYBo

    Level III Supporter

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  9. karlStolz

    karlStolz Member

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    AC systems need to be charged by weight, not by pressure in order to get the correct charge. Anything else is a crap shoot.
     
  10. NYBo

    Level III Supporter

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    You're absolutely right, Karl.

    The refrigerant charge weight should be listed on the a/c sticker under the hood.
     
  11. Rick Anderson

    Rick Anderson Well-Known Member

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    The FSM often has a chart that provides pressures against ambient temp and hi-side pressure line temp. The idea is there will be a relationship between the pressure and the temps in the system and outside the system for a certain quantity.

    Granted a less precise way of gauging the amount refrigerant in the system, but its something. Agreed, you really can't tell unless you weigh it. Can't weight it, then you have to take a guess based off the pressures and ambients for the system.
     
  12. mightymo

    mightymo Guest

    I'm trying to recharge my '94 Caravan 3.0 A/C. I bought a couple of cans of r134 at wal mart, one has the pressure guage. I've never done it before so I don't know what make of this. My A/C compressor is cycling on and off along with the fan about every 20 seconds. With the refill canister hooked up (engine running, A/C MAX) the pressure guage goes up to the green when the compressor is running, and drops back down to below the green when it shuts off. If I press the fill button the can, the pressure guage goes up into the red zone, indicating to me some sort of life-threatening explosion. So my questions to all you experts out there:
    1. Does this compressor cycling indicate a bigger problem?
    2. Am I doing this recharge correctly?
    3. Any suggestions?
     
  13. NYBo

    Level III Supporter

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    Cycling every 20 seconds probably means the refrigerant charge is a little low. You need to slowly open the valve on the fill kit and keep the gauge in the blue. However, if you open it just a tiny bit and the gauge goes to red, you have other problems.
     
  14. 00Molavi

    00Molavi Member

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    So on a recent trip to Vegas when the outside temp was 106+ I noted that when stuck in traffic the AC is not cooling as I would like it. It actually is weaker than my '95 Mitsubishi. Anyways today the recharge kit and gauge was on sale in Kragen for $20, got it and the pressure is actually in the blue zone. So I guess the AC on these cars are generally weaker. Someone told me that the piping on the Dodge AC is shorter than imports and it takes a while to feel the AC cold, any credibility to this?
     
  15. Rick Anderson

    Rick Anderson Well-Known Member

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    Longer piping would increase your cool down time, shorter piping would decrease the cool down time. How quickly the AC cools down and temp difference with ambient (outside) temp is dependent on a lot of factors, NOT ONLY if the refrigerant is topped off.

    The lower the pressure in the condenser, the low side fitting that is used for servicing, the lower the temperature of the condenser. If your cheapo recharge kit from Kragen is showing a pressure greater/lesser than desired, then you're not making the desired temperature. Remember, too cold and the condenser freezes up and doesn't circulate air.

    The difference in pressure between the hi and low side of the cooling system will produce the temp difference from ambient.

    Under or Over Serviced, the AC will NOT produce its full cooling capacity.

    Remember a Van is much larger volume inside than a small import, which will increase the cool down time.
     
  16. oil dude

    oil dude Guest

     
  17. oil dude

    oil dude Guest

    First time posting on here but it is easy to put freon in you could buy a hose with a guage on it and follow the directions only thing is you dont want air in the system you may have to evacuate the system first.. also use the high mileage r134 it has seal conditioners that can actually stop some leaks due to shrinking seals
     
  18. rdtony

    rdtony Guest

    Correct me if I'm wrong but the evaporator is aluminum and cannot rust out? I flushed mine this summer (@ 157,000 miles) and the outlet lines wer aluminum, so I assume the evaporagtor is too. The condenser is one very solid chunk of aluminum, and for the record the expansion valve looked brand new even at 157K!!

    And btw, I went to the scrap yard and got a window air conditioner, took it all apart and saved the compressor and use it for my vacuum pump; it will pull 28HG in less than 4 minutes and hold it all day. Cost: $5
     
  19. Tecqboy

    Tecqboy Member

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    This is my 1st time posting on this forum. I've searched this forum about my question and found other's have had this issue before, but I couldn't find a difinitive answer / solution.

    I have a 2002 Tnc. The rear A/C works great; gets really cold. But, the front blows only mildly cooled air. The car went to the dealer for repair. I was told that the system is properly charged and all the blend doors were working properly and no gas leaks were detected. This happens even when the engine is cold, so no hot water in the heater core either. I've spent a lot of money at the dealer and it doesn't work any better than when I took it in. I went to an independant shop and was told only a dealer has the right diagnostic tools to check out the system properly.

    Since the rear system works OK, that eliminates the compressor and condenser, no? Where / how does the compressed gas "split" between the front and rear systems? Any help or insite would be greatly appreciated.
     
  20. gusc

    gusc Member

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    ]94Grand just about said it all but I would like to add a few of my own.


    -I would never have the guts to liquid charge, the risk is too great. Also, there is absolutely no reason to shake a freon can, this does nothing. It is not a paint can!! However, the can does need to be warmed with hot water or hot air.

    -As has already been said a couple of times, always blow the air out of the charging hose. Air (moisture) kills AC systems. Also, don't open the charge valve until the comp is running unless the system is empty. The reason for this is that without the comp operating the low side press can be high enough to blow out the freon can, especially when the system is hot from previously running.

    -The engine must be at least at fast idle to create enough suction to suck out the freon from the can, idle isn't enough.

    -I've been mixing 12 and 134 for years with no problems. I've converted three or four of my oldies by just adding 134 to the old 12 charge. Remember when 134 first came out and we were told the comp, evap and cond all had to be replaced for the changeover?? That all turned out to be bull.

    -There is an oil which is compatible to both 12 and 134. I don't remember what it is but your auto parts guy knows.

    -I would rather have too little oil than not not enough. Oil is not compressible, it won't work well in the compressor if there is too much. If I find any sign of oil leaking I will use one of those 134 cans with oil, they don't have much, after four or five regular cans.

    -Either adding freon by weight or using a sigh glass has never worked for me. After all these years my system is to add freon slowly until the AC vent temp is between 30-40 and stop. Works every time.

    -If a system is only low I connect the charge hose, start the engine, slowly open the charge valve, hang the can down near something hot on the engine, drive until the AC starts to cool or until I think the can is empty and then remove it or change to a new can. It has taken me about 40 years to arrive at this system but it is only for small topping off jobs, not empty systems.
     

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