Confused about thermostat for 308QV | Page 3 | FerrariChat

Confused about thermostat for 308QV

Discussion in '308/328' started by robertcope, Sep 23, 2021.

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  1. kcabpilot

    kcabpilot Formula 3

    Apr 17, 2014
    1,614
    California SF bay area
    Full Name:
    Paul
    You quoted my post, perhaps you didn't read it.
    "the hot extension is greater than the distance of the cold position to seat"
    The overall travel is not critical so long as it seats, the spring will compensate for travel beyond the point where contact is made providing an 8-10 mm buffer or range without creating stress.
     
  2. TonyL

    TonyL F1 Rookie

    Sep 27, 2007
    4,239
    Norfolk - UK
    Full Name:
    Tony
    Apologies i didnt quite understand your description!
     
  3. AZDoug

    AZDoug Formula 3

    Jun 17, 2009
    1,613
    Along the Verde , AZ
    Full Name:
    Doug
    I am a trained mechanic. I am also a machinist and degreed engineer. I haven't done auto mechanics for a living since oh, 1980, but some things you don't forget how to do. :)

    Doug
     
    smg2 likes this.
  4. AZDoug

    AZDoug Formula 3

    Jun 17, 2009
    1,613
    Along the Verde , AZ
    Full Name:
    Doug
    I forgot to mention, i used a VW Golf T-Stat, ($11 or such) 54 MM, it did NOT come with a rubber "C" ring, so i used the 56 MM rubber ring off the old 'stat.

    That maybe where the issue arose,and my solution was a1 MM copper , mandrell formed wire to insert inside the rubber C gasket to take up the slack. or, just buy a 56 MM 'stat with C ring.

    Doug
     
  5. robertcope

    robertcope Formula Junior
    Rossa Subscribed

    May 3, 2021
    275
    Houston, TX
    Full Name:
    Robert B. Cope
    FWIW, I swapped the OEM thermostat back in. No real change in operation.

    I decided to try and verify the water temperature vs the gauge. After a bit of testing, it looks like the gauge is reading 15-20F high. This lines up with when the fans start running, too. If we believe that is true, then on the highway, probably running 180F or so and sitting idle in traffic about 195F.
     
  6. thorn

    thorn F1 Rookie

    Aug 7, 2012
    3,324
    Tallahassee, FL
    Step one: if you suspect the thermostat, boil it in water and check the opening temp.
     
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  7. robertcope

    robertcope Formula Junior
    Rossa Subscribed

    May 3, 2021
    275
    Houston, TX
    Full Name:
    Robert B. Cope
    Well, I think this thread documented it well, but it wasn't the basic operation of a brand new thermostat that I question. And I still think there are plenty of good questions to ask about new thermostats vs the OEM unit. But yes, I did test the OEM unit before putting it back in.
     
  8. GordonC

    GordonC F1 Rookie
    Owner Rossa Subscribed

    Aug 28, 2005
    4,166
    Calgary, AB, Canada
    Full Name:
    Gordon
    Coolant gauge problems are often the source of suspected hot running issues! I ran into this with my 84 QV also, where the gauge would sometimes show an expected operating temp around 195, then would equally often climb to 215-220. The problem was resistance buildup in the contacts of the instrument panel harness and gauge connections. The solution was to remove the instrument panel, clean the contacts on the harness connectors and on the back of (every) gauge, and add an additional ground connection to the instrument panel harness.

    Question - with ignition on or engine running, what happens to the gauge pointers on the small gauges (fuel, coolant temp, oil pressure) when you turn your lights on? With the degraded panel harness connections, my small gauges would all jump 2 needle widths when the park or headlights were turned on - I'd gain 1/8 tank of fuel, 10* coolant temp, and 10 psi oil pressure! After the harness cleanup, those needles all stay stable when the lights are turned on.

    Recent discussions about coolant temp gauge issues:
    More tales of flakey temp gauges
    308 temp gauge question

    I posted details about the instrument panel maintenance (good time to switch to LED lighting as well) in the thread
    308 gts dash led conversion , post #15

    Cheers,
    Gordon
     
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  9. robertcope

    robertcope Formula Junior
    Rossa Subscribed

    May 3, 2021
    275
    Houston, TX
    Full Name:
    Robert B. Cope
    Went and tested this.. started the car, turned on the lights, and yes, my small gauges jumped a needle width or so. Guess I have some connections to clean, etc!
     
  10. edworak

    edworak Karting
    Silver Subscribed

    Jun 10, 2007
    107
    Genoa, Nevada
    Full Name:
    Ed Dworak
    After reading the original post I ordered the 109671A unit from SuperperformanceUK. I just received it hence the delay in responding. The gasket included was correct not as depicted in the picture. The thermostat package also came with two different "O" rings both of which should work. Just in case I ordered a 105192 "O" ring. Any of the three should work but I won't know until I disassemble the outlet where the part installs and determine which works best. The top disk on the thermostat measures 55.75mm in diameter and the bottom disc measures 32.70mm in diameter. The thermostat is marked 82 degrees C which by my calculation is 180 degrees F which is fine by me. I'm also changing the fan sending unit on the bottom of the radiator to an 82 degree C unit. I live in Nevada so the car always seems to run a little hot. For reference my car is a 1982 308GTSi/U.S. spec car which I've owned since 1987. If you read Birdman's cooling article he mentions drilling a small vent hole on the top portion of the thermostat disc for system air venting. My old thermostat had a little dimple on the top disc for drilling the hole but the one I just received doesn't have anything so I will be carefully drilling a small hole for air venting before installation.
     
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