456gt overheating when idle

Discussion in '456/550/575' started by Angel Bello, Esq., Aug 26, 2006.

  1. Angel Bello, Esq.

    Dec 10, 2003
    I own a 1995 456gt. The car runs perfectly, except when idling, when it overheats, almost reaching the red zone on the temperature gauge.

    The auxiliary fans engage seemingly fine. I use Motul coolant.

    Any suggestions?

    Any info on a campaign with a larger diameter pulley to make the water pump run at higher rpm's ?
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  3. Diablo456

    Diablo456 Karting

    Jul 27, 2006
    Try searching, this has been covered before.

    And it would be a smaller diameter pulley to increase pump speed.

    Don't they teach this stuff in Esquire School anymore?
  4. beckertb

    beckertb Rookie

    Feb 28, 2004
    Beaumont TX
    Full Name:
    Also, make sure both fans are kicking on. I was having this problem and it turned out to be a bad connection on one of the relays--only one fan was kicking on. It made a dramatic difference in temps after the fix.

    Good luck,

  5. ernie

    ernie Two Time F1 World Champ
    Lifetime Rossa Owner

    Nov 19, 2001
    The Brickyard
    Full Name:
    The Bad Guy
    To add to what the others have said, you may want to change the thermostat out for a new one.

    Make sure that your cooling system is properly bled. You want to have the heater on and turned to the hottest setting. That way you are sure to get all of the air out of the system.

    Try adding some Reline Water Wetter to your coolant.

    Finally, you may even want to consider having an aluminium radiator made.
  6. vlamgat

    vlamgat Formula Junior

    Jan 9, 2004
    If this problem started relatively recently, I would check the coolant (presumably done) and assume its a fan problem. If its gradually been getting worse, then it sounds like a failing t-stat and there may also be a fan problem. Check that the aux fan comes on when the A/C stop button is depressed.
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  8. ww_k

    ww_k Rookie

    Aug 2, 2006
    Full Name:
    I had my cooling system completly checked just last week by the official Ferrari dealer as I experienced similar high temperature in stop and go traffic. According to them, nothing wrong.
    I still get the temperature running high, but actually never in the red. I finally convinced myself that I will stop worrying unless it shoot in the red zone, or stop driving in central Tokyo heavy traffic..
    Anyway it seems 550's are also experiencing overheating problem, and you may have a look in those chat as well find if any of the solution may apply to 456.
  9. synchro

    synchro F1 Veteran

    Feb 14, 2005
    Full Name:
    This thread on upgrading the fans

    I also use distilled water rather than tap water as it has fewer contaminants in the system. You can also alter the antifreeze to water ratio (reduce antifreeze quantity) as water has a higher capacity for heat transfer.
    Be careful if you live in freezing locations though.
  10. jcurtis

    jcurtis Rookie

    Apr 14, 2005
    Laguna Beach, Ca
    Full Name:
    Jack Curtis
    The previous owner of my car had the same problem. The dealer installed a new (different....maybe upgraded?) water pump. Since then, I have never had a problem of overheating even in 2 horrible hours of stop and go traffic on the I-5 last July!
  11. Angel Bello, Esq.

    Dec 10, 2003
    I'd like to truly thank all the responses.
    I appreciate all of you for taking the time and effort.
    Will keep posting and sharing the advances, and hopefully solution, to my
    problem. Angel.
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  13. oss117

    oss117 F1 Rookie

    Jan 26, 2006
    Plantation, Florida
    Full Name:
    Hello Angel,
    If your car overheats at idle (but not when it is in motion) chances are it does not get enough air flow when the 2 fans are supposed to kick in (i.e. one of them is not working).
    However, take your time to read the owner manual: it is very well written and you will find there all the advice you need to figure out the nature of the probelm and how to care for the cooling system of your car.
  14. Angel Bello, Esq.

    Dec 10, 2003
    Mil Gracias, Alfredo.
    My problems have not ended. If you have the time, take a look at my new thread.

  15. oss117

    oss117 F1 Rookie

    Jan 26, 2006
    Plantation, Florida
    Full Name:
    Hello Angel,
    Do you still have cooling problems?
    If you have replaced your coolant, much care is required to bleed all the air out of the cooling system.
    Turn the heater on to max. heat and run the engine at idle until the thermostat opens up and the coolant starts circulating.
    It will take a few minutes.
    Add coolant as the air bubbles out.
    Squeeze with your hands the cooling hoses to help with the process.
    Also remember the best coolant is pure water and the more antifreeze you add the less cooling effect you get, so use only what is necessary in the area where you live.
    Have the thermostat checked or replaced and make sure the cooling fans are both operating.
    I am assuming the fins of the radiator are all in good order and there are no restrictions to the air flow.
    Hope it helps.

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