A/C VARIABLE ORIFICE VALVE ???

Discussion in '6.9L IH & 7.3L IDI Diesels' started by MIDNIGHT RIDER, Jul 2, 2008.

  1. MIDNIGHT RIDER

    MIDNIGHT RIDER Full Access Member

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    On my 1985 Ford diesel, factory air converted to R134a, where is the orifice valve ??

    Can I use the variable orifice valve ??

    If so, I replace the plain one with the variable, right ??

    If I can use the variable one, what part # do I need, where do I get, and how do I install ??

    Thanks.
     
  2. RLDSL

    RLDSL Diesel fuel abuser

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    For the variable orifice valve you order Factory Air or Four Seasons part number 38904 They carry it in store at Advance Usually have to order that one in, but they will generally get it for you in a day .

    Generally the orifice tube is in the last fitting right before the evaporator housing. Follow the line from the condenser to the evaporator housing and it will be where the hose goes from narrow to large, that is the point where the orifice is inserted in the line.
    On the later ones you need a spring lock tool to open the connector if yours has a funny looking coupler there, you have a spring lock coupler and you will need to spend about $6 on a little line tool to pop that sucker loose or you'll hate yourself in the morning. Older fittings are just coupled normally with two wrenches and use a new O ring, and Nylog to seal it. Do not use pag or ester oil on ac orings, it dries them out and you will get leaks
     
  3. MIDNIGHT RIDER

    MIDNIGHT RIDER Full Access Member

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  4. RLDSL

    RLDSL Diesel fuel abuser

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  5. MIDNIGHT RIDER

    MIDNIGHT RIDER Full Access Member

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    Thanks, and I am glad I asked, as I probably would have gotten the wrong one.
     
  6. MIDNIGHT RIDER

    MIDNIGHT RIDER Full Access Member

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    I got my 38904 variable orifice valve, a newly made replacement hose, new set of gauges, Robinaire MasterVac pump, etc., all gathered up and ready to go.


    I pulled the old original orifice valve, much like pulling a stubborn tooth.

    The new valve, though entirely different in looks and construction, measured to be identical in diameter and body length to the one I pulled out.

    Try as I might, after numerous flashlight examinations, long sharp tool probings, and lots of generous cussing, along with plenty of lubricant, the new valve (and the old one, for that matter) refused to slide in as deep as the old one.


    Soooo........, I left it in as far as it would go and let the remaining length protrude into the hose end that screws over it.


    It should still do it's job, but I wish I could have gotten it to fit as the original.
     
  7. Exekiel69

    Exekiel69 Registered User

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    When I last did the ac I made a mistake and put the orifice tube the wrong way did You try both ways?




    Also RLDSL, the part # You posted gives 5 results and I can't tell exactly which one is it, could You please post it if You know.

    Thank You.
     
  8. RLDSL

    RLDSL Diesel fuel abuser

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    The factory Air and Four seasons ones are exactly the same, they are both manufactured by Nartron Corp so get the cheaper factory air one.

    We just finished installing one in friends '99 expedition this evening. 33 deg out the ducts in the dash, 34deg out the ducts in the rear air third row seat ;Sweet
     
  9. MIDNIGHT RIDER

    MIDNIGHT RIDER Full Access Member

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    It definitely is not installed backwards.

    Neither the old or the new would fit in as deep as the old one originally was.

    Since these things are made of extremely flimsy plastic, one can't force the dumb $30-plus thing down in there, as it will just collapse.


    As for the brand-name, the box mine came in says Factory Aire By Four Seasons.
     
  10. RLDSL

    RLDSL Diesel fuel abuser

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    As long as it is in far enough to where the orings are sealing, and the two pipes will go back together, that is all that matters ;Sweet
     
  11. MIDNIGHT RIDER

    MIDNIGHT RIDER Full Access Member

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    That makes me feel better.

    I was expecting icicle-cold air, after all this money/work, but in mid-90* heat, around 50* at the vents at idle is all I am seeing.

    Cruising at 40-mph, it isn't much better; I haven't had opportunity to go faster.


    A few weeks ago, before the dumb hose started leaking, I was regularly seeing low-40s at the vents, that with the plain old orifice tube.

    At idle, MAX-A/C, on two seperate gauges, I have 44-whatever on the gauge.


    That is about what it always had before the hose replacement episode.
     
  12. RLDSL

    RLDSL Diesel fuel abuser

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    You should be WAY colder than that. If it's mid 90's with that VOV you should be nice and comfy.It sound like you have other problems as well. What exactly was the ambient temp and what was the presuree reading on the low side? check this at a high idle of about 1200 or so after 5 minutes with the ac on high wndows up

    You may still be fighting too much hot water. the heater valve mod in the tech articles does wonders
     
  13. Mr_Roboto

    Mr_Roboto Full Access Member

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    Question - how long did you evacuate the system for? As soon as the system is open the dessicant starts absorbing moisture from the air. It takes time for the water to "boil" back out under vacuum.

    I don't open systems so I'm not sure of the minimum time, however on a standard evac / recharge of an unopened system my machine recommends 30 minutes minimum. I would venture to guess that on an opened system the time would increase to hours.

    If you have free moisture inside the system it will create internal icing and obstruction of coolant.
     
  14. MIDNIGHT RIDER

    MIDNIGHT RIDER Full Access Member

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    I have a MANUAL ball-valve in the heater-hose that stops all flow to the heater-core.





    I had use of a Robinaire MasterVac big monster-sized machine.

    I let it pull for a little over an hour, then let it sit under vacuum for around 30-minutes.


    I reckon the black plastic pointy-end of the VOV should point downward toward the evaporator, and the flattened mesh-filter end toward the condenser, right ??
     
  15. LCAM-01XA

    LCAM-01XA Full Access Member

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    Dumb question - when you touch the line above and below the orifice tube, what should the temperature be? Mine gets real hot above it (towards the condenser) and very cold below it (towards the evaporator), but my drier never gets cold, just barely cool...
     

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