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AC Repair Checklist

Discussion in '365 GT4 2+2/400/412' started by miami355, Aug 15, 2020.

  1. miami355

    miami355 Karting

    Sep 2, 2006
    134
    Miami, FL
    1984 400i in very hot and very humid Miami Florida. I plan on driving my car weekly, but only if AC is sufficient to handle the South Florida climate. Searching AC related posts, there seems to be no consensus on how good or bad the factory system is. I've seen users describe their AC as freezing cold, or marginal at best.

    I need to get my AC up to par by any means necessary. Its just not cooling in its current state. I really think no other climate is like a Miami hot and humid summer, so its going to be a challenge.

    I have dual AC with a new upgraded Sanden compressor R134, and the 2 radiator and 1 condenser fan operational. Any tips and tricks? I would consider going with a parallel flow condenser if needed.

    I also have a slow freon leak, which is doesn't sound like fun to chase down, but at this point, I'm willing to have the interior taken apart. I'm going to take the car to Tim Standford in Fort Lauderdale, but would like to go in with a game plan. Thanks for any help and advice.

    David
     
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  3. Ak Jim

    Ak Jim F1 Veteran
    Rossa Subscribed Owner

    Dec 23, 2007
    5,467
    North Pole AK
    Not an expert but everything I’ve read talks about needing about 25% more condenser surface area when switching from 12 to 134.
     
  4. raemin

    raemin Formula Junior

    Jan 16, 2007
    768
    Lyon (FR)
    Full Name:
    R. Emin
    The stock dual AC is quite strong (longer stroke on the compressor and dual evaporators), unfortunately these cars were not meant to be stuck in the traffic jams, so when the car is static, there is not enough airflow so as to cool down the condenser. Also the water screen on the evaporator is often clogged to the point it does not let the fan work properly.

    On the later cars, there are 3 additional ASTI Gates fans (the yellow ones), these allow proper cooling of the condenser regardless of the speed of the car. This is probably the sort of upgrade I would consider for Florida.

    I've totally removed the water screen from the evaporator: I receive from time to time a few droplets of water, but the airflow imporvement is like night and day.

    I quite do not see the point in upgrading to the compressor.

    If you change the gas you do also have to change the evaporator valves as they are adjusted slightly differently. So if you want to reclaim all the cooling power of your system, these have to be replaced.

    Upgrading the condenser should also be contemplated. These condensers are standard size unfortunately they do rely on the old types of connector. If you change the hose fittings, an upgraded condenser is easy to source.

    All in all, this could be your upgrade path (in the following order) :
    1) remove clogged screens
    2) retrofit the 412 fan mounts together with 3 ASTI fans (these were used in Lotus cars and the old Renault Traffic trucks)
    3) replace the valves
    4) replace the condenser
     
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  5. miami355

    miami355 Karting

    Sep 2, 2006
    134
    Miami, FL
    Thanks for the advice. Where are the water screens? You said later cars had three additional fans, but I’m not sure what you mean. My car has three fans, two in front of the radiator, and one behind. You mean later cars have a total of six fans?
     
  6. raemin

    raemin Formula Junior

    Jan 16, 2007
    768
    Lyon (FR)
    Full Name:
    R. Emin
    1) water screen. the cabin blower under the dashboard includes a rectangular piece of cloth (foam ?) that captures water droplets.

    2) fans. you've got 2 Lucas style fans in front and one ASTI (yellow) fan behind the radiator. The 412 has 2 more yellow fans. https://www.ferrarichat.com/forum/threads/1986-ferrari-412i-gt-chassis-60359.623795/ : on this listing, the third (right) fan is not easy to spot, but you get the idea.
     
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  8. Temerian

    Temerian Karting
    Silver Subscribed

    Jun 17, 2014
    164
    Manhattan
    Full Name:
    Rick Temerian
    Hi Raemin,

    I'm about to upgrade my series 1 AC system and would like to change to 134. Would you suggest the same path? The system worked pretty well when I refilled it with R12 but there are multiple leaks and the freon didn't last long. I'm not sure how available R12 will be in the future. The engine is out of the car now so it seems a good time to replace the coolant hoses. Thanks in advance for your advice. Rick
     
  9. gsholz

    gsholz Karting
    Silver Subscribed

    Jan 21, 2006
    171
    Oregon
    Full Name:
    Jerry
    #7 gsholz, Aug 17, 2020
    Last edited: Aug 17, 2020
    I would keep a working R12 system as long as you can find R12 refrigerant. R134a may not cool as well (depends on the efficiency of your condenser, you may need to experiment with the amount of charge and superheat). You'll need to replace all hoses as R1394a will permeate the old hoses. Compressor oils are not compatible (use polyoester). Your compressor's seals may also need to be replaced.
     
  10. raemin

    raemin Formula Junior

    Jan 16, 2007
    768
    Lyon (FR)
    Full Name:
    R. Emin
    #8 raemin, Aug 17, 2020
    Last edited: Aug 17, 2020
    You should use r416: that's r134 with 3% butane. The butane just takes care of whatever old oil remains in the system (pure r134 solidify petroleum based oil which plays havoc with the compressor) .

    That's what I had on mine. Works well and does not leak, but does not cool as well as r12.

    I am now upgrading the system with new hoses a bigger condenser, new expansion valve, new seals and POE oil. This way I can use straight r134.
     
  11. rubenpadron

    rubenpadron Formula 3
    Silver Subscribed

    Oct 22, 2013
    1,040
    SF Bay Area, CA
    Full Name:
    Ruben
    A properly functioning AC should do fine in FL... my 412, also with dual AC, with differences noted by Raemin, cools amazingly well in 100+F degree temps here in CA.

    Good luck!

    Ruben
     
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