89 Testarossa Boil over

Discussion in 'Technical Q&A' started by jacksftr, Mar 7, 2021.

  1. jacksftr

    jacksftr Rookie

    Aug 12, 2015
    Car hadn't been started ifor 3 months. Noticed car was getting hot while warming up. When cool, added one gallon of G48. Slowly heated up. After short drive (temp stayed @250), a major boilover occurred.. How big a problem is a stuck thermostat?
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  3. flash32

    flash32 F1 Rookie

    Aug 22, 2008
    Central NJ
    Full Name:
    Did fans turn on

    Sent from my moto g(7) using Tapatalk
  4. Steve Magnusson

    Steve Magnusson Two Time F1 World Champ
    Lifetime Rossa

    Jan 11, 2001
    Full Name:
    Steve Magnusson
    #3 Steve Magnusson, Mar 7, 2021
    Last edited: Mar 7, 2021
    +1 -- First thing to do is stick your hand in front of the rear tire on each side when the engine is running and the water temp gauge is over ~200F to confirm/deny warm airflow from the water fans.

    If bad, second thing to do inspect the water radiator fan connections in the horizontal j white connector at the fuse-relay panel:

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    (After ensuring the fuses are OK) Another way to test the water radiator fans is to remove the water radiator fan relays and use a jumper wire to connect the female terminal 30 in the relay socket to the female terminal 87 in the relay socket:

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    The corresponding water radiator fan should run (even with the key "off"). If each fan does run with the jumper in place, but both never turn "on" when the relay(s) are in place = probably a bad thermoswitch in the bottom of the LH (IIRC) water radiator (give a shout if you need to test this -- using a jumper between the negative battery terminal and one of the terminals on the fuse-relay panel is easier than crawling under the car to get to the radiator thermoswitch).
    V4NG0 and flash32 like this.
  5. gfrench

    gfrench Rookie

    Mar 14, 2006
    Had a boiling problem with my Testorossa some years back.

    It was returned to me from service from an authorised Ferrari agent. When I ran it it boiled. On investigating I found that the coolant system had not been bled following the post belt change refill. There are two air bleeds at high level close to the rear bulkhead.

    With the amount of fluid you have added it is worth a look to see if it is a bleeding / trapped air issue
    GTUnit likes this.
  6. Motob

    Motob Formula 3
    Professional Ferrari Technician

    Nov 11, 2003
    Berkeley, CA
    Full Name:
    Brian Brown
    There are bleeder screws on the aluminum coolant pipes on each side of the engine (they look like brake bleeder screws. There is also a brass bleeder bolt on the thermostat housing. In the old days (before getting an Airlift system), I would always bleed the air out of the system using these bleeders.

    You have to be very careful with the bleeder screws on the aluminum pipes, as they are steel and they corrode and seize in the pipes. If they don't want to come out, leave them alone, or they will destroy the threads in the pipes. The bleeder on the thermostat housing is a must do.

    Since using the Airlift system to add coolant to the car, I don't have to worry about messing with the bleeder screws again.

    Brian Brown
    San Francisco Motorsports
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