Temp sensor

Discussion in 'General Maverick/Comet' started by wolfheads, Apr 3, 2021.

  1. wolfheads

    wolfheads MadMav

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    I was having a small coolant leak where the temp sensor connects to the fitting on the intake. Come to find out, the sensor was bottoming out inside the intake and wouldn't seal properly. I found a small extension that would raise the probe sensor apx 1/2 inch and fixed the leak. However, the temp reading is about 20 degrees lower than it was. My question is: Can that probe be shortened, about 1/8th inch to eliminate the extension and allow the probe to sit further down in the flow of coolant in order to get the correct reading? Or would that ruin the temp sensor?
    Thanks guys.
     
  2. bmcdaniel

    bmcdaniel Senile Member

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    Company I used to work for made temperature probes and specs called for the thermistor to be within 1/16" of the end.
     
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  3. Constable

    Constable You have the right to remain silent....or not!

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    I don't believe you can mess with sensors or you may ruin them. They are designed the way they are for a reason.
     
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  4. Krazy Comet

    Krazy Comet Tom

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    Cut probe & it's end of sensor.

    A lower temp may well be correct. Measurement is of coolant, not the metal surface heating coolant, though I'd think temp would be within 10* or so.
     
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  5. wolfheads

    wolfheads MadMav

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    Well I know what the constant highway temp was, (around 180), and now it's reading around 160.
     
  6. joerockne

    joerockne Member

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    I am going to put a gauge on mine also. Is that right there on the drivers side of the thermostat housing? It looks like there is a wire to the idiot light there now, I am assuming.
     
  7. CaptainComet

    CaptainComet Large Member

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    Are you sure you have all the air out of the system? It will read low if not.

    If you have installed a coolant recovery system on these cars, that fixes a lot of that.
     
  8. joerockne

    joerockne Member

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    I always put a very small hole, like 1/16" or smaller in the thermostat also. Eliminates any chance of an air pocket when you fill it up with coolant.
     
  9. bmcdaniel

    bmcdaniel Senile Member

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    I go more and bigger, three 1/8" equally spaced holes around the thermostat flange.
     
  10. Krazy Comet

    Krazy Comet Tom

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    While it's easier to purge air on a refill, more than one 1/16 hole hinders warmup, especially in cold weather. Of course most of us aren't driving our toys in really cold weather.

    I pulled and tossed a new stat that was in F150 when I bought it, had three holes in it. Took over 20 minutes to get decent heat & another 10 before it was really cookin. For refill, I disconnect the heater hose from intake to heater core, fill through that. When coolant dribbles out the intake connection, it's full. When I replaced the plastic intake on wife's Grand Marquis last fall, I filled block through thermostat opening then installed stat.
     
  11. joerockne

    joerockne Member

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    That was my feeling as well. I want the air to pass but not to flow meaningful amounts of coolant through it.
     
  12. bmcdaniel

    bmcdaniel Senile Member

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    I dunno. I started drilling the Mav thermostats like that back in the '70s, never had a problem with heat in the PA winters. The car was my daily driver for 12 years.
     
  13. joerockne

    joerockne Member

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    Whatever works . I do sort of like the 3 holes idea, since the thermostat is horizontal on a 302 . For sure having a hole near the top would be good. Since the stat sits flat in a Chevy you don't have to worry about that.
     

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