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Help please, car overheating...odd

Discussion in 'Boxers/TR/M' started by bpu699, Oct 27, 2019.

  1. bpu699

    bpu699 F1 World Champ
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    1987, 17,000 or so miles, did the major myself about a year ago...

    Was driving with my daughter, last drive of the year...car running great... it’s 55 degrees out here, chilly...

    Car is running great, but temp needle is always at the middle, or 1 mm over...odd, as it’s cold out side...

    At stop signs it nudges right, about 1-2 mm, barely over the middle mark.

    Get on the highway, goes down slightly, it still above the middle by a mm or so...

    I turn on the heat, as it’s getting cold in the car. Heat doesn’t work, BLOWS cold?! Press all the knobs, no change. Odd, as it worked after the major when I bled the system...

    Park the car...temp shoots up to the 3/4 mark. Fans do NOT go on... double odd...heater still blows cold...

    Wtf???

    Checked oil level, normal, no intermixed coolant
    Checked coolant, normal, no milkshake...
    Checked connectors in the frunk... normal, no burnt connectors...

    Now I know this can be 2 separate issues, but what would make the heater blow cold, and fans fail?

    The heater blowing cold throws me. Electrical issue with a valve somewhere? Air bubble???

    Plan next weekend is to jump the fan relays, make sure they work. I also think there is a temp sensor in the right radiator. Need to jump the sensor see if that works too.

    But again, the lack oh hot air throws me?

    This can’t be a stuck thermostat, can it? I would think if it were driving wouldn’t bring the temp down...

    The water pump impeller couldn’t have worked loose, could it? I would think that would cause catastrophic overheating, moving or not...

    Any help appreciated.
     
  2. fridolin_pt

    fridolin_pt Rookie

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    Yes, it can.
     
  3. Steve Magnusson

    Steve Magnusson F1 World Champ
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    #3 Steve Magnusson, Oct 27, 2019
    Last edited: Oct 27, 2019
    No, the heater should work regardless of what the thermostats are doing -- so either an electrical problem or something like a kinked heater hose.

    This does seem like a thermostat problem. You should be able to do some diagnosis just with some careful touching of some of the tubes. If the thermostats are in the correct position to send the hot coolant exiting the cylinder heads to the radiators, the tubes 33 and 34 here:

    https://www.ricambiamerica.com/car-diagrams/ferrari/v12/testarossa-group/testarossa-1990/cooling-system.html

    should be the same (hot) temperature as pipes 4 and 5 here:

    https://www.ricambiamerica.com/car-diagrams/ferrari/v12/testarossa-group/testarossa-1990/engine-cooling.html

    If either tube 33 or tube 34 seem much cooler = bad sign for that thermostat. The radiator fan thermoswitch is only in the LH radiator, so if it's tube 33 that seems cool, that would explain the radiator fans not coming "on" even though the dash gauge is reporting above normal.

    Of course, no radiator fans condition could be an electrical problem (but you already know what to try there).
     
  4. turbo-joe

    turbo-joe F1 Veteran
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    this sounds for me as if there is air in the cooling system. bleed the sytem first on all 3 bleeders and see what is going
     
    Babalouie and Steve Magnusson like this.
  5. bpu699

    bpu699 F1 World Champ
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    Thanks guys, will do all as suggested, and will report back next weekend...

    Is changing thermostats fairly simple? Those thermostat bolts look aweful to get to...
     
  6. turbo-joe

    turbo-joe F1 Veteran
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    only the 2 to the front of the car :)
     
  7. bpu699

    bpu699 F1 World Champ
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    Is there a cross reference on the thermostats? I see the Ferrari part is $150, each...

    Seems a tad high for what is certainly a generic part...
     
  8. turbo-joe

    turbo-joe F1 Veteran
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    BMW has the same, but don´t know what type - sorry

    but it is unusual that both thermostats going wrong.
    use an infrared thermometer and meassure the temperature on both radiators top and buttom. the switch for the radiator fans is only on the left radiator. I put in a second switch also in the right radiator at my competition.

    you bleeded the system already?
     
  9. bpu699

    bpu699 F1 World Champ
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    Cant work on it til this weekend. Will find the laser thermometer...its somewhere in the garage...somewhere
     
  10. ross

    ross Three Time F1 World Champ
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    its the thermostat.

    but, i once had a funny one on the 512tr where i could not figure out the overheating-like issues, and it turned out to be the rubber gasket on the radiator cap that had worn out and was not sealing correctly.
     
  11. turbo-joe

    turbo-joe F1 Veteran
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    sure?
    I doubt that just at the same time both thermostats going wrong?
     
  12. ross

    ross Three Time F1 World Champ
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    what makes you think both of them have to be bad?
     
  13. turbo-joe

    turbo-joe F1 Veteran
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    I don´t think so ross. also I have written before that I doubt that just at the same time both thermostats going wrong?

    you have written the thermostat and so I understand you mean both.
    may be missunderstanding?
     
  14. bpu699

    bpu699 F1 World Champ
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    I think he is suggesting if the left thermostat goes bad, the left radiator doesn't heat up, and the fans don't go on...
     

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