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  1. #1

    Default Help! Mechanics can't figure out AC's odd behavior

    I've been having weird air conditioning issues with my 2001 Suburban. Generally, I'll run the AC for an hour or two and then it will stop flowing. I can hear the fan blowing, but the air stops coming through the vents. After a while, the air randomly starts coming through the vents again. This is only the front AC, not the rear.

    I've also noticed that there is almost always a light fog on my windshield.

    Then this morning, after the car had been parked all night, my wife drove off and I saw a bunch of water come out from under the front of the car -- as if the AC had been on for a long period of time and water was dripping.

    I'm wondering if it's possible that there is water getting stuck somewhere in the AC or the ducting. If so, this would explain the water in the morning (after the car hadn't been driven for 12 hours) and the cold air stopping after a long time of using the AC, but coming back on randomly (as if the water somehow drained and allowed the air to flow again.

    I recently had the AC system recharged. There were no major leaks, but it need about 3 pounds.

    I also do a lot of off-road driving -- in fact the car is off-road most of the time -- so the car gets jostled a bunch and a lot of dirt and sometimes rocks get thrown up against the chasis.

    Any help or troubleshooting suggested appreciated.

  2. #2


    I am certainly not an expert, but I have heard of A/Cs freezing over.Im not sure how to fix it, but you might be able to test it. Does it stop working after a while if it is not on full blast?
    Jaridd - Texas

    01 Chevy Silverado z71

  3. #3


    interesting. so basically it gets so cold that it freezes over and the cold air stops coming through. you turn it off for a while, it thaws out and blows again.... is that what happens?

  4. #4
    Legend Mean_Green_95's Avatar
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    Apr 2009
    Baton Rouge, Louisiana, United States


    in order for an ac to freeze over, the coils would have to be clogged, by mud or dead leaves, or what not. Check your condenser and coils.
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  5. #5


    Any idea how I would identify the coils to see if they are clogged?

    I did have the back AC drain clogged with mud. The whole cargo area was soaking wet.

  6. #6
    Legend Mean_Green_95's Avatar
    Join Date
    Apr 2009
    Baton Rouge, Louisiana, United States


    Make sure the condenser up front is clean, not caked with mud or nothing. Check your cabin filters if you have them.

  7. #7


    Not sure if the newer models use vacuum motors to control air flow, but the older trucks use them. A vacuum leak at these motors could cause air to get routed to the wrong location causing you to think it's not working anymore. If you drive alot of off-road with the truck, the drain line for the condensor could be clogged and causing the water buildup to occur in your passenger footwell. However, those should be two unrelated, but coincidental issues.

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  8. #8


    check the belt for burning, your compressor might be seizing up, very common issue. most other problems would surface right away, not after a couple of hours, except the compressor. that truck take 3 lbs total of R-134, so i don't know how a recharge can take 3 lbs, as you stated.

    you might of has some a-hole so the ac work and he did not pull vacumn on the system, or not long enough, so there is moisture inside your systems causing ice to block the expansion orifice, which is another condition that can occur after a few hours, although not as likely as a bad compressor.

    lastly, your system might be out of lubricant, or have to much, either one can cause your symtoms.

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