Is My 87 GN A/C Supposed To Be So Lame?

Discussion in 'The Big Chill' started by 2manybuicks, Aug 26, 2018.

  1. 2manybuicks

    2manybuicks Platinum Level Contributor

    I bought the car new here in South Florida.

    No noise from the blower motor. Never been replaced. Car is essentially stock.

    Air seems to mosey out of the outlets with blower on high. I think it was always like this, but maybe it has slowly degraded over the years and I have just gotten used to it.

    Keeps the car kinda cool in August, but it aint great. Window leaks don't help, but still...

    Is it supposed to be kinda lame?
  2. buick64203

    buick64203 Just plum crazy Staff Member

    Sounds like you have a blower motor issue. When you put it on high, you should really hear the air blowing out. IIRC, the blower motor is pretty easy to access isn't it? Shouldn't take you more that a few minutes to diagnose if the blower motor is bad
  3. 2manybuicks

    2manybuicks Platinum Level Contributor

    I mean, when it is on high it just seems like a newer car set on low. Each position on the fan switch does give a different speed, so it isn't like I lost a speed. It just aint real impressive.

    So air flow -- yes. Air velocity -- not great.
  4. buick64203

    buick64203 Just plum crazy Staff Member

    First thing I would do is put it on high. On high the blower motor gets full 12v. So you can pull the wire off the motor and test to see if your getting full 12v. The blower speed selector switch could be NG as well.
  5. FJM568

    FJM568 Well-Known Member

    Also check under the dash and make sure all the ducts are still connected.
  6. Briz

    Briz Platinum Level Contributor

    Sounds like a damper issue to me. Does the air come out where its supposed to when the selector is set to A/C. or all the vents at the same time?
  7. sriley531

    sriley531 Buckle up, this could get rough....

    Forgive my ignorance, but do GN's have cabin filters? I've seen filthy cabin filters hurt airflow before.
  8. Luxus

    Luxus Gold Level Contributor

    No, GNs are before they started to do cabin filters. At least I'm sure they don't have one.
  9. sriley531

    sriley531 Buckle up, this could get rough....

    Ok, wasn't sure. Thanks for confirming.
  10. gsgnnut

    gsgnnut Well-Known Member

    The AC in my 87 GN is ice cold ( 40 degree outlet temp) and the blower moves some good airflow out of the vents.
  11. gsgnnut

    gsgnnut Well-Known Member

    it does sound like a tired blower motor. piece of cake to swap out too.
  12. 2manybuicks

    2manybuicks Platinum Level Contributor

    Thanks all. Time to do some investigating.
  13. 1973gs

    1973gs Well-Known Member

    Put some ac gauges on it. If the high side is normal and the low side is high, it's possible that the outside of the evaporator core is plugged, not allowing air to flow through it. Low side pressure that is high could also be caused by a weak blower motor. Is this still r-12? If it was converted to r-134, it wont be as cold as r-12.
  14. 2manybuicks

    2manybuicks Platinum Level Contributor

    Thanks. Will do. Not so much a "not cold" issue as a "weak flow" issue.
  15. 1973gs

    1973gs Well-Known Member

    All air that flows to the inside of the car goes through the evaporator core, whether it's in heat or ac mode. It's very common for the evaporator core to leak. This allows them to get covered with ac oil and then dirt sticks to it, blocking off air flow. Even if the evaporator isn't leaking, a lot of air has flowed over that core and with no hepa filter, a lot of dirt too.
  16. 2manybuicks

    2manybuicks Platinum Level Contributor

    Okay, had it in the shop. My mechanic pulled the blower motor and found that some dumb ___ had swapped the rotor / impeller for a smaller size. Now fixed.

    Plus yes, leaves and other debris everywhere. Now cleaned out.

    Much better flow. So you guys were pretty close to right. Thanks.


    It was in the shop because I was about a mile from the house and heatd the sound of the AC change. Quickly hit the Scanmaster and saw a voltage of 10.8. Limped home with 9.8 left.

    Anyway, charged the battery, fix3d a loose wire at the alternator but now the AC compressor won't kick on. So mechanic swaped a relay which he said is controlled by the ECM. Still won't kick on. Says no ground / signal from ECM.

    He hotwired the relay and it all works. But I would like it fixed right.

    Local GN guy says he has never seen ECM-related AC problems.

    (My mechanic is a corvette guy but is trying to figure this out.)

  17. GNandGS

    GNandGS Well-Known Member

    There are A/C mentions in code but doubtful your issue is at ECM.


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