Paging all A/C folks

Discussion in 'Tow Rigs and Trailers' started by 1-tonmudder, Jul 10, 2018.

  1. 1-tonmudder

    1-tonmudder Doin my part to stir the pot.

    Joined:
    Apr 17, 2005
    Location:
    Greeneville TN
    I have on 01 CCLB F350 w the 7.3.For several years it had a very good ac,so much so Tonya kept a blanket in the back seat for long trips.In the last couple of years the a/c just hasn't worked as good.Last summer the comp clutch cover was soo wore out if just fell off and quit working.I put a new clutch and cover (shimmed correctly) and it was back to working but still not like it should.The summer before I replace the fan and while it worked it just wasn't as cold.

    My garage has been full and I haven't really had a chance to look at it close but Im about to tear in to it and want to know what I might be over looking or missing before I start buying parts.

    A/C condenser is beat up pretty bad down low.I am also having higher than normal trans temps and I feel the closed fins on the condenser are the problem since the trans cooler is directly behind the condenser.Could the extra heat from the fluid in the cooler be affecting the temp of the a/c?? Could heat be bleeding off the trans cooler back in to the condenser???

    Fan speed seems to be correct w the switch position,when checking from the drivers seat.I am going to pull the fan from the box and check speed and also Im going to use a endoscope I have to check for a clogged evaporator.System does make water that puddles under the truck.

    Went to check the vent temps today and my vent thermometer was MIA.Got side tracked and didn't get back to it.Will try again tomorrow.

    Clutch does stay engaged,does not cycle on/off like its low on gas.I have an appointment later this week to put the gauges on it to confirm exact pressures.

    Blend door motor does seem to work but heater box under the dash seems loud(er) some times more than others.What is the correct way to test/check the blend door motor???

    So what have I forgotten/overlooked/not mentioned??? Trying to have my ducks in a row before I tear in to it.
    @Tim C @RHSCTJ maybe????
     
  2. Croatan_Kid

    Croatan_Kid How's your hammer hangin'?

    Joined:
    Nov 4, 2007
    Location:
    New Bern
    I kinda scanned through that real fast....but have you looked at the fan clutch? If it's worn out, it won't pull as much air as it should which would cause the AC and trans temps to be warmer than normal.
     
  3. RHSCTJ

    RHSCTJ Well-Known Member

    Joined:
    Jul 1, 2008
    Location:
    ROCK HILL, SC
    Im not familiar with those trucks but it may have a heater bypass valve not fully closed that could be letting hot water in to the heater core. Is the low side line ice cold?
     
  4. 1-tonmudder

    1-tonmudder Doin my part to stir the pot.

    Joined:
    Apr 17, 2005
    Location:
    Greeneville TN
    It sounds/appears to be working correctly.When it locks up you can definitely tell its engaged.
     
  5. 1-tonmudder

    1-tonmudder Doin my part to stir the pot.

    Joined:
    Apr 17, 2005
    Location:
    Greeneville TN
    It does not have a valve and it will frost the low side line.
     
  6. Tim C

    Tim C Wizard

    Joined:
    Jan 22, 2007
    Location:
    Fayetteville
    The correct way to check the blend door motor is to look at it with a mirror to see if it moves or listen to the air change pitch as it moves from hot to cold. With a warmed up engine if the air switches to ambient or cooler to scorching hot then it's working. The motors usually work or don't and the door if broken won't switch at all.

    Definitely check the evaporator with a borescope. If it's plugged up there will be little or no airflow. Just installed a new Evap on the local housing authoritys f250 because it was leaking but it had a black mat of dust and debris covering it and very little airflow.

    For a proper diagnosis I'd like to get low and high side readings at start up and 5 minutes later with all windows up and Max cold high fan selected. Plus the ambient air temp at the time. If you could beg, borrow or steal a gauge set and get those numbers I can help you pinpoint it.

    As far as general AC diag, the condenser fins aren't helping you and could very well be the transmission issue. With high mileage the Teflon piston rings Ford used in the compressors are probably gone and it isn't pumping 100%. That's what causes the Ford AC black death you can find on google.

    If you have to open the system, get a variable orifice tube from any parts store, that alone dropped the vent temps from 60 to 45 on my old 03 f250. It has a spring loaded check ball that acts as a smaller orifice at low rpm for better cooling, and high rpm high flow pushes the ball open to the stock orifice size.

    If you don't have a heater valve, get a Ford one, it's not much more than Chinese junk ones but will last longer and add it to the heater inlet hose, hook the grey vacuum line that hooks to the evaporator housing to it, that's what it's for. If you have one already disregard that.

    Also you can mist water on the condenser through the grill to see if the vent temps drop. If the fan clutch is weak or the fins are blocking air flow that would help them out. This isn't a foolproof test though because water is better at conducting heat than air anyway so it will drop the temps and pressure on a good system too.

    Generally on a 90 to 100 degree day I like to see low side between 35 and 45 and high between 225 and 275, that's just a general ball park. Both reading higher is a sign of condenser airflow problems, high side low and low high is a bad or worn compressor.

    Sent from my HTC6545LVW using Tapatalk
     
    Last edited: Jul 11, 2018
    shawn and RHSCTJ like this.
  7. RHSCTJ

    RHSCTJ Well-Known Member

    Joined:
    Jul 1, 2008
    Location:
    ROCK HILL, SC
    If the low side line is cold I would say its probably not a refrigerant issue, probably a blend door. Hard to say without knowing the line pressures and vent temperature. Bring it down to rock hill and ill put some gauges on it for you!
     
    Tim C likes this.
  8. RHSCTJ

    RHSCTJ Well-Known Member

    Joined:
    Jul 1, 2008
    Location:
    ROCK HILL, SC
    @Tim C is obviously more knowledgable on the fords than I am but ill add that a big ass fan in front of the truck can help you figure out if its an airflow/ fan issue but you really need to see what happens with the pressures and vent temps when you add airflow.
     
    Tim C likes this.
  9. Tim C

    Tim C Wizard

    Joined:
    Jan 22, 2007
    Location:
    Fayetteville
    He posted the line was cold while I was typing all that on my phone lol but I agree if the low side is cold on both sides of the accumulator then it's pretty close to properly charged and working normally as far as the refrigerant is concerned (air flow, pumping, etc) it sounds like at that point it's airflow in the cab, such as a blocked or dirty evaporator or a stuck blend door.

    Pressures will tell for sure obviously.

    Sent from my HTC6545LVW using Tapatalk
     
    RHSCTJ likes this.
  10. Jody Treadway

    Jody Treadway Croc wearing fool Moderator

    Joined:
    Mar 20, 2005
    Location:
    Hendersonville, NC
    All I have to add that has not already been said is my 99 super duty had the exact same issues. Mine ended up being that the evaporator was covered in Alaskan Malamute fur...
    I replaced the evaporator while I had it apart and everything is restored back as good as new
     
  11. jeepyjman

    jeepyjman Well-Known Member

    Joined:
    Sep 22, 2007
    Location:
    Concord
    I never understood why it took some auto manufacturers so long to run cabin air filters.
    also to add its really hard to diagnose an a/c problem without gauges. A set is cheap at harbor freight
     
    Tim C likes this.
  12. shawn

    shawn running dog lackey of the oppressor class Administrator

    Joined:
    Mar 13, 2005
    Location:
    Raleigh, NC
    Truth. I bought a set off of Amazon for $50.

    In fact, I used them last night.
     
  13. Tim C

    Tim C Wizard

    Joined:
    Jan 22, 2007
    Location:
    Fayetteville
    My home AC gauges are Hf. I tossed the crappy quick connects though and bought a set of the quick connect screw down ends from the mac truck, they fit right on the Hf hoses.

    And some manufacturers still don't have the message, my 16 f250 has no cabin filter. At least they went back to expansion valves, o-tube systems suck.

    Sent from my HTC6545LVW using Tapatalk
     

Share This Page