A/C Issues... after replacing the evaporator core

Discussion in 'Gen 2 Prius Main Forum' started by PapaWill, Sep 24, 2020.

  1. PapaWill

    PapaWill Junior Member

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    I have been working on getting the A/C working for several months now... I knew i had a leak and finally charged the system with dye and freon to see if I could pinpoint it. Nothing was showing up and the charge would last for a few months. Finally I got the bright idea to shove a stiff wire with a big of cloth on the end up the condensate hose and sure enough I got dye on the cloth. I dug into the dash 3 weeks ago and replaced the Evaporator core and ll associated O rings. I did not replace the expansion valve. Put it all back together and the coldest it will get is about 62 degrees. The pressures are right in the range for this temperature: 40 and 200 psi. So before I did the fix, the A/C worked normally and got plenty cold.... not any more. Anyone know what might be going on here? Thank you in advance!
     
  2. AlexY

    AlexY Junior Member

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    Not enough oil? Maybe you lost some during replacement, some of it is circulating with coolant.
     
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  3. PapaWill

    PapaWill Junior Member

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    At the time of recharging the system, I also added a couple of ounces of ND 11 oil… Of course I was guessing on the amount but not sure that could cause the issue...
     
  4. PriusCamper

    PriusCamper Senior Member

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    This is a variable pressure system and can't be refilled with refrigerant based on pressure readings. You have to evacuate the entire system and precisely measure the exact weight of required amount of refrigerant and oil and then re-fill the system. The way you currently are doing it is going to lead to a dead air compressor soon... What's more proper servicing of A/C system requires measuring temp & humidity inside the cabin, outside the car and within the system. Finding a shop with near brand new and highest quality equipment is what's going to fix this.
     
  5. AlexY

    AlexY Junior Member

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    Problem is with oil, most of it is trapped in the compressor, I don't know if there is perfect way to measure this amount. Evacuation of the system doesn't remove it in full. I've swapped compressor after evacuating with vacuum pump and there was still quite a lot of oil in it.
     
    #5 AlexY, Sep 25, 2020
    Last edited: Sep 25, 2020
  6. PriusCamper

    PriusCamper Senior Member

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    The very expensive machine that reputable automotive A/C service centers use evacuates the system in full and there is no guessing with amount of oil and refrigerant, it is a precise measurement based on Toyota OEM specs... Too much or too little oil or refrigerant = dead compressor.
     
  7. Leadfoot J. McCoalroller

    Leadfoot J. McCoalroller Senior Member

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    Did you fill this thing from a vessel on a scale? If you get the charge off by more than a few grams you'll have reduced efficiency somewhere in the system. It needs a precise charge to work right.
     
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  8. PapaWill

    PapaWill Junior Member

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    I use the scale and I used the 12 ounce cans. That means I added one 12 ounce can and them another 4 ounces by weight to get to the recommended amount as per OEM specs. No was it exact? I doubt it but I have never ever in the history of putting Freon in a Prius had any difficulty using this method. My point is: the whole system worked just perfectly before I installed the new evaporator core. I appreciate the advice to take the car to a shop where they have new equipment and can flush the entire system, but I don’t really understand why or how that would help. The last thing I want to do is “kill“ the compressor but I really do want this thing fixed right! One other symptom I noticed is on the high-pressure side where the tube coming from the evaporator core is usually very hot... it is only very warm. So it would appear to me that the new evap core is not acting as efficiently as it should. Thank you for all your input as I merrily blunder on…
     
  9. SFO

    SFO Senior Member

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    Sounds like you never actually sold the '07 to the people who didn't care if it had a working A/C ?

    Now that you're a few months into this repair, maybe @lech auto air conditionin will chime in again and get you pointed in the right direction.
     
  10. lech auto air conditionin

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    1: A couple of post ago you said you added a couple of OZ. of oil !!! ???.
    The whole entire system only takes about 3 oz.
    (“One other symptom I noticed is on the high-pressure side where the tube coming from the evaporator core is usually very hot... it is only very warm. “)
    You are talking about the small thin liquid line going to the expansion valve.
    It should be warm not very hot about 20° over ambient temp.

    The large suction pipe coming back to the compressor should be in the 40’s F

    I’m banking on vary over oiled or could you have some how have heater blend air coming on at the same time ?

    try this test.
    1: car sitting over night cool.
    2: start can in morning immediately turn on air conditioning for max cold.

    a: dose it get cold and low side 28psi to 31 psi ?
    Then after Engine coolant gets hot low side pressure goes up and your duct Dash temperature goes up ?

    Both radiator fans coming on ?

    DENSO OEM condenser? or cheap after market condenser?
     
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  11. PapaWill

    PapaWill Junior Member

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    Good memory SFO! That was actually another car and no, they did not care about the A/C working.

    LECH: I made an error about how much oil was added. I added 1/2 an ounce... ostensibly to recoup the oil lost in the evap core.
    I FNALLY checked out the car w/ TS and I get a code of B1442, meaning the air inlet is not opening working correctly... Either the servo motor or perhaps I did not get all the vents actuating correctly... So it looks like I got to tear into the dash for a second time and see what's up there. Could that be the whole problem? I am guessing yes, if ambient air is mixing with cooled air... Another day and a half adventure... I WILL keep you posted!
     
  12. lech auto air conditionin

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    Hopefully sounds like you’re on the right path but ambient air would normally not give you these bad results but heater core air would.

    Unless you had a hot engine hot fan hot radiator blowing hot air that was 110f to120° Because the hood was up while you were taking these measurements , in the fresh air mode into the corral located just below your window feeding air right into the evaporator.
    Now that scenario will give you some higher low side pressure’s and higher duct Dash temperatures
     
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  13. PapaWill

    PapaWill Junior Member

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    Thanks Lech. I have not been able to work on it recently, but I did use TS again to check the B1442 code is still present. I wet inside TS (Active data, I think) to see if i could move the fresh air inlet and I cannot. It is stuck at 49.5%. I can manipulate the other components of the A/C but not the air inlet damper. It looks like I have to take the entire dash out again and see if I missed a servo plug or something like that? Bad servo motor? I should be able to get to it in a week or so...
     
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