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Hvac not working correctly HEAT blowing out alot of moisture

Discussion in 'Ford Trucks' started by superdutypsd, Nov 12, 2015.

  1. superdutypsd

    superdutypsd Senior Member
    Messages: 175

    Anyone good with ac hvac on these truck 2007 6.0 f350 in summer i vac down my system and recharged my truck runs and idles 10-12 aday, the ac would work for a few hours then cut out i would get out and tap the clutch to rengage the ac, now with heat on its blowing out alot of moisture, the heat works but you can feel the humidity in thr cab and the deforst actually ends up fogging up the windows more at first. What do i need to fix for dry air again
     
  2. Randall Ave

    Randall Ave PlowSite.com Addict
    Messages: 1,943

    There should be a drain for the moisture. Does it smell like antifreeze?
     
  3. FredG

    FredG 2000 Club Member
    Messages: 2,188

    Possibly the start of heater core. Check and see if there is any moisture around passenger side floor area.
     
  4. superdutypsd

    superdutypsd Senior Member
    Messages: 175

    Were can i find this at
     
  5. superdutypsd

    superdutypsd Senior Member
    Messages: 175

    No moisture around floor, all dry
     
  6. superdutypsd

    superdutypsd Senior Member
    Messages: 175

    My low side is cycling between 25-55 and high side cycling between 100-125, anyone no what it should be high and low and i do not smell any coolant
     
  7. I think you have a bad heater core.
    As far is your ac, that is a totally separate issue.
     
  8. superdutypsd

    superdutypsd Senior Member
    Messages: 175

    But with the moisture in the heat, and ac cuting out some times, this could be from a bad evap, i know the heat comes from coolant and ac from ac system but i thought the evap drys the air for both systems
     
  9. superdutypsd

    superdutypsd Senior Member
    Messages: 175

    Were is the heater core located on these trucks anyway to test them, im half temped to just replace everything i have 9200 hours on the engine and 325,000 miles owned since new 2007
     
  10. First of all, Unplug your compressor pump and see if you still have the issue.
     
  11. LapeerLandscape

    LapeerLandscape PlowSite.com Addict
    Messages: 1,587

    That's what I was going to suggest, unplug the A/C comp out at the clutch.
     
  12. superdutypsd

    superdutypsd Senior Member
    Messages: 175

    When im at idle ac works fine but the clutch will then disengage high side reading 210 and low side reading 25/30 when the compressor shuts off the low side goes up to 65 and high side drops down to 75, if i get out and tap the clutch it will engage the ac, if im doing 75mph ac will work as usual. With heat on i do not hear the ac compressor cycling, i was told that the evap, is also used for the heat not just for the ac, i do not know if this is true, i just know basic basic ac hvac on cars and trucks
     
  13. tjctransport

    tjctransport PlowSite.com Addict
    Messages: 1,390

    ac compressor engages for defrost, not for heat.
     
  14. superdutypsd

    superdutypsd Senior Member
    Messages: 175

    Ok yes i do remember hearing it with defrost on, could my evap be going bad or could the moisture be from the clutch not engaging on the ac when defrost is on
     
  15. Whiffyspark

    Whiffyspark 2000 Club Member
    from SOMD
    Messages: 2,402

    Your clutch shouldn't be cycling with it on. You need to have a proper charge put in and then go from there. Pressures don't mean much

    The Windows fogging is usually sign of heater core going. None of this has to do with evap
     
  16. FredG

    FredG 2000 Club Member
    Messages: 2,188

    If you do diagnose it to a heater core, Your suggestion on replacing the high mile truck might be a good idea. Heater cores are expensive and labor intensive. should be located behind the dash.
     
  17. Randall Ave

    Randall Ave PlowSite.com Addict
    Messages: 1,943

    If you let it sit and run with the A/C on, does it drip water like it should?
    There is nothing wrong with the evaporator. The drain is plugged, should be at bottom of heater box. If the drain is fine, replace the heater core, not that bad to do.
    But with that many miles, she'd be down the road. :nod:
     
  18. superdutypsd

    superdutypsd Senior Member
    Messages: 175

    I was refering to the heater and ac units, i have a new truck i order from ford thats suppose to be delivered after winter and i will keep this as a work truck, as far as the repair i have the tools and can do myself i have pulled my cab twice amd tore the motor down twice, i have high miles but the body and motor are in great shape really, and mostlike highway miles i do 300 a day and 80-100k a year
     
  19. superdutypsd

    superdutypsd Senior Member
    Messages: 175

    The system has the proper charge and was vaccum down to -30 and held for 45 min before recharging to proper weight
     
  20. superdutypsd

    superdutypsd Senior Member
    Messages: 175

    Yes theres a puddle under truck when ac is on, i guess i will replace the heat core and ac clutch and see how things go from there, this truck did a 100k miles from this time last year, like to get another year or two out of it as a work truck before replacing, as i aready have a new one coming in a few months from ford