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AC Problems

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by AntAZBlaz, Apr 15, 2002.

  1. AntAZBlaz

    AntAZBlaz 1/2 ton status

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    Hey
    It’s starting to get hot again and here comes my AC question. I have had my system checked and updated to the new coolant type. I went back and had it checked for leaks and was told that there does not seem to be one. I have switched the fan and I still do not get much out of my AC unit. I know that something is wrong because one time I was looking at a Suburban that was the same year as my Blazer and it was colder and the fan seemed to be blowing harder than mine. I have gone through my system and put foam seals between all the joints to make sure that I was not losing pressure to leaks but that still has not solved the problem.
    I’m considering making a step up voltage for the AC unit to make the fan blow harder but before I do does anyone have any suggestions on what I could do get to AC cooler?
    Anthony
     
  2. dyeager535

    dyeager535 1 ton status Premium Member

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    On high the AC fan (or heater fan) sees 12V. Have you made sure that the doors inside the box are actually working correctly? If they stay in the closed position, and the fan is on, you won't get any or much air. The fan isn't likely to be the problem if you can hear it running on high.
     
  3. AntAZBlaz

    AntAZBlaz 1/2 ton status

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    Hey
    Is that the door down by the passenger area? I’ll check on that this weekend but would think that it is opening up because it is blowing. But for an example if I put my hand near the back rest area of the seat I can barely feel the air blowing. But the time that I checked out the suburban it felt like my hair was being blown back what kind of performance do you get out of yours?
    Anthony
     
  4. dyeager535

    dyeager535 1 ton status Premium Member

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    Mines not an AC truck, but I put the Heavy Duty Heater setup in it, so it is extremely effective. Its basically just an AC fan mounted on a non AC box with a fan motor cooling hose.

    Since mine is not an AC vehicle, I'm not able to shut the airflow off really. The box I have is set up for it, but the heater control unit is not...the lever that shuts external air off, at least on my inner heater box, is the closest one to the passenger side of the vehicle...but I'm not sure with AC if there is such a thing there, (everything is cable actuated on mine except fan speed obviously) or if its a big vacuum diapraghm. This you may want to check though, even if its not working correctly, you should be able to manipulate it by hand.
     
  5. dyeager535

    dyeager535 1 ton status Premium Member

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    BTW, please click reply on whomevers post you are responding too, that way they get an e-mail notifying them if they have selected this. (like myself)
     
  6. AntAZBlaz

    AntAZBlaz 1/2 ton status

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    No problem. I'm going to check out the duck work on Thursday and then I'll let you know if that door is opening for me. How far away can you feel the breeze from you fan? the fans are the same arn't they? Any one else got any input?
     
  7. mike reeh

    mike reeh 1/2 ton status

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    is your vacuum door setup working? On the intake manifold there is a vacuum tee and one of them leads to the checkvalve/reservoir usually mounted on the pass. side of the firewall, its a black ball shaped thing.. then from there its real small like 1/8" rubber line into the cab. make sure its all hooked up. when mine was unhooked, the fan didnt blow very hard out of the vents.. when I hooked it all up, it would move the doors inside to blow HARD on max/ac out the dash vents... of course the motor has to be running for this stuff to work. but if you start your motor, let it run for 30 seconds (rev it a few times) then shut it off and be real quiet, move the vent/heat/ac selector knob around and you should hear both vacuum leaking out, and the doors moving.. if not, this is your problem

    mike
     
  8. dyeager535

    dyeager535 1 ton status Premium Member

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    I can feel the fan in the back seat, but barely. The ductwork isn't all that efficient IMO at directing air through the rest of the vehicle. It does great for the front seaters and defrost, but the rest of the interior is an afterthought in the heating process.

    The fans are NOT all the same, although all receive 12V when on the "high" setting. The AC/HD heating fans are the same, but they are much more effective than the "standard" fans. The only visible external difference I have seen is the hole for the cooling vent on the motor case. The "standard" no AC/HD fans are absolutely pathetic. The "squirrel cage" fan on the AC motor is bigger than both the HD and Standard heater, but the larger fan doesn't make much of a difference at all IMO, the majority of the difference is in the RPM of the fan when on the "high" setting. I'm sure the other settings are at higher RPM's as well, but "high" on the AC/HD setup feels to be about twice as much as "high" on the lesser heater setups.

    I guess as long as you could put some kind of filtered port in that hole, you could use the AC/HD motor in a "standard" heater setup.
     
  9. AntAZBlaz

    AntAZBlaz 1/2 ton status

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    Hey
    Can you give me a little more info on that line coming off the manifold maybe if you can find a picture and point out the parts? I wasn’t sure if I was looking at what you had mentioned or not. I checked the vacuum door setup and that is working fine. I felt the coolant reservoir and it was freezing compared to what I feel I’m going to spend some time and cover it over with heat shield material to hopefully keep some of the heat off of the system. My truck is an 86, I don’t know if that can help you at all.

    Thanks for your help.
    Anthony
     
  10. AntAZBlaz

    AntAZBlaz 1/2 ton status

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    Where do you get the HD fan from, I could not find any different motors when I was looking for the replacement one that I put on last year.
    Anthony
     
  11. dyeager535

    dyeager535 1 ton status Premium Member

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    Like I said above, a HD fan is the same as an AC fan. The only difference between HD and AC is the fan "squirrel cage" which doesn't come with replacement motors anyways. Both the AC and HD fans have a hole in the motor case to keep the motor cool, while the "standard", non HD/AC fan does not.
     
  12. Impex

    Impex 1/2 ton status

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    can you buy something like a "super squirrel cage" that moves more air?
     
  13. AntAZBlaz

    AntAZBlaz 1/2 ton status

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    i was thinking that if there was a different fan blade pitch or number of blades that it would do the same thing. i havent found anything though
     
  14. dyeager535

    dyeager535 1 ton status Premium Member

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    No. Blade pitch difference *might* work, but I wouldn't count on finding something different.

    The problem is that the HD and non-AC heater boxes are the same, except the HD heater engine side box has a port for the cooling fan. The same meaning they are the same depth. If you put an AC fan on there, the fan hits the firewall well before the motor can be bolted up.

    Took me until AFTER I fabbed up a plastic spacer to see that it was a stupid idea, the spacer allowed the fan to fit, except now the extra length of the fan was just blowing into the spacer : ) Thankfully, I didn't mount it up before I realized that, and tried an AC fan for the heck of it, not expecting the motor itself to be the major difference, but it is.
     

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