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Thread: A/C issue

  1. #1

    Default A/C issue

    Recharged my A/C last night after rebuilding the motor. Now the car runs hot, when I turn the A/C ON. When I turn the A/C off it cools down to the midway point on the gauge which is where it always runs at even on these 110* Arizona days. I have a fluidyne aluminum radiator and contour fans both running on high speed. Before I rebuilt the engine the car would run at the mid way point on the gauge with or without the A/C on. The only difference from then to now is the electric fans now, versus prior I had the stock clutch fan on it. Any ideas guys?

  2. #2
    FEP Senior Member gt4494's Avatar
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    May sound dumb but are both fans pulling air through the radiator?
    "If you can't explain it simply, you don't understand it well enough."
    Albert Einstein

    1984 20th Anniversary GT350
    Almost "Stock"

  3. #3

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    That would be my first look too. You have a aftermarket temp gauge? If not I would get one of the ether ones and pop it on there for a bit. Voltage changes can do stupid things to the stock gauges.
    1984.5 G.T.350 5.0 CFI AOD Convertible (TRX package, loaded)
    K&N filter in a stock dual snorkel, GT40 heads, Edelbrock 3721 intake, MSD 8456 Dist., MSD 8227 coil
    Comp cams XE254H, hypereutectic pistons
    Hooker Super Comp Shorty Equal Length Headers, catted BBK H-pipe, full custom duals
    Maximum Motorsports caster/camber plates and strut tower brace, 3.73 rear, dura grip (both Yukon)
    Ford Performance Springs, Firehawk A/S 225/55r16 on LMR TRX r390 wheels (street)
    Federal 595 rs-rr 245/40r17 and 255/40r17 on OE cobra r wheels (race)
    AOD rebuilt with a 6 clutch direct drum, Koline steels stacked with 8 clutches, Kevlar band, superior shift kit, new torque converter. --Everything else stock and fully functional.

  4. #4

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    Quote Originally Posted by gt4494 View Post
    May sound dumb but are both fans pulling air through the radiator?

    Yes the fans are wired to draw air threw the radiator, not push it. I have been driving the car since I rebuilt the motor and engine bay and never a cooling issue, until now with the A/C working

  5. #5

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    I compared my data logging on the laptop to my stock gauge, and they are pretty much dead on with each other.

  6. #6

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    The car ONLY runs hot with the A/C on. It's 117 outside and i can drive/sit in traffic don't matter no A/C car stays cool. But if the A/C is on? Thats a different story. Sitting in traffic it gets hot, and city driving it does as well. Not over heating hot. but get's hotter than normal without A/C.

  7. #7
    FEP Senior Member gt4494's Avatar
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    Nov 2004
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    Chas. SC
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    OK, when the AC is on it automatically runs at least one fan. Correct?
    "If you can't explain it simply, you don't understand it well enough."
    Albert Einstein

    1984 20th Anniversary GT350
    Almost "Stock"

  8. #8

    Default

    And by "cool" what temperature are we talking about here?
    1984.5 G.T.350 5.0 CFI AOD Convertible (TRX package, loaded)
    K&N filter in a stock dual snorkel, GT40 heads, Edelbrock 3721 intake, MSD 8456 Dist., MSD 8227 coil
    Comp cams XE254H, hypereutectic pistons
    Hooker Super Comp Shorty Equal Length Headers, catted BBK H-pipe, full custom duals
    Maximum Motorsports caster/camber plates and strut tower brace, 3.73 rear, dura grip (both Yukon)
    Ford Performance Springs, Firehawk A/S 225/55r16 on LMR TRX r390 wheels (street)
    Federal 595 rs-rr 245/40r17 and 255/40r17 on OE cobra r wheels (race)
    AOD rebuilt with a 6 clutch direct drum, Koline steels stacked with 8 clutches, Kevlar band, superior shift kit, new torque converter. --Everything else stock and fully functional.

  9. #9

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    Yes I actually have it wired to run both fans at the same time all the time.

  10. #10

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    Quote Originally Posted by emerygt350 View Post
    And by "cool" what temperature are we talking about here?
    I want to say it was about 180ish...

  11. #11

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    When you say contour fans do you mean fans for a Mercury Contour? They would be sized for an I4 engine not a V8. I tried a couple of electric fans on my 5.0 and was never satisfied. Needle always going to L in «*Normal*» when sitting in traffic air on or off. I put the clutch fan back and everything is good. Radiators are usually sized to give about a 40 degree temperature drop. If you can get your hands on an IR thermometer (Harbor Freight for cheapos) check upper and lower radiator hoses. When you put the AC on the condenser is dumping heat into the air in front of the radiator. Raising 110 deg air by 40 puts it at 150 for entering the radiator rather than the usual 50-110 you might be seeing in AZ. You need to move a lot more air to get equivalent cooling at those higher temps.
    W

    As always, "It ain't what you don't know that gets you, it's what you think you know that just ain't so."

  12. #12

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    Quote Originally Posted by WilliamCapri View Post
    When you say contour fans do you mean fans for a Mercury Contour? They would be sized for an I4 engine not a V8. I tried a couple of electric fans on my 5.0 and was never satisfied. Needle always going to L in «*Normal*» when sitting in traffic air on or off. I put the clutch fan back and everything is good. Radiators are usually sized to give about a 40 degree temperature drop. If you can get your hands on an IR thermometer (Harbor Freight for cheapos) check upper and lower radiator hoses. When you put the AC on the condenser is dumping heat into the air in front of the radiator. Raising 110 deg air by 40 puts it at 150 for entering the radiator rather than the usual 50-110 you might be seeing in AZ. You need to move a lot more air to get equivalent cooling at those higher temps.

    I say contour, meaning the ones LMR sells. Thats the thing it can be 112 outside here no A/C on and I'm at about 180 ish ( on the "R/M") all day long at a stop don't matter. But when I cut the A/C on is when the temp goes up to about the "AL" on the gauge. When I'm at "R/M" my live data log says about 180ish.

  13. #13

    Default

    Do you know what it is at a/l?
    1984.5 G.T.350 5.0 CFI AOD Convertible (TRX package, loaded)
    K&N filter in a stock dual snorkel, GT40 heads, Edelbrock 3721 intake, MSD 8456 Dist., MSD 8227 coil
    Comp cams XE254H, hypereutectic pistons
    Hooker Super Comp Shorty Equal Length Headers, catted BBK H-pipe, full custom duals
    Maximum Motorsports caster/camber plates and strut tower brace, 3.73 rear, dura grip (both Yukon)
    Ford Performance Springs, Firehawk A/S 225/55r16 on LMR TRX r390 wheels (street)
    Federal 595 rs-rr 245/40r17 and 255/40r17 on OE cobra r wheels (race)
    AOD rebuilt with a 6 clutch direct drum, Koline steels stacked with 8 clutches, Kevlar band, superior shift kit, new torque converter. --Everything else stock and fully functional.

  14. #14

    Default

    Quote Originally Posted by emerygt350 View Post
    Do you know what it is at a/l?
    I don't since it's never been that hot... I might just have to hook up my logger and see this weekend. Eventually I want to replace all the gauges with actual number gauges. These work and look great, but I like numbered gauges....

  15. #15

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    Yeah, and they are all a little different. I have an oil temp and oil pressure gauge in my car. I used to have coolant temp too but after learning what temps were on my stock gauge I took it out. My car rides between n/o and when spirited driving occurs it might park itself between o/r. I'd I turn on the air it will move that same distance if I am sitting and idling. Have not paid too much attention while driving with ac. I tend to pay more attention to oil temp anyway.
    1984.5 G.T.350 5.0 CFI AOD Convertible (TRX package, loaded)
    K&N filter in a stock dual snorkel, GT40 heads, Edelbrock 3721 intake, MSD 8456 Dist., MSD 8227 coil
    Comp cams XE254H, hypereutectic pistons
    Hooker Super Comp Shorty Equal Length Headers, catted BBK H-pipe, full custom duals
    Maximum Motorsports caster/camber plates and strut tower brace, 3.73 rear, dura grip (both Yukon)
    Ford Performance Springs, Firehawk A/S 225/55r16 on LMR TRX r390 wheels (street)
    Federal 595 rs-rr 245/40r17 and 255/40r17 on OE cobra r wheels (race)
    AOD rebuilt with a 6 clutch direct drum, Koline steels stacked with 8 clutches, Kevlar band, superior shift kit, new torque converter. --Everything else stock and fully functional.

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