No temp and odd noise.

Discussion in 'Troubleshooting & Diagnosis' started by CT1275, Sep 16, 2020.

  1. CT1275

    CT1275 Member

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    Hi, a couple questions here, prior to removing my old engine (gen1, 350) the temp sender and guage worked. Put new engine in (gen2, 383), and guage cluster was rebuilt and now not getting temp reading. Thought thermostat wasnt opening but all the hoses are hot and I'm getting heat in the car when running the heater. The car was definitely run long enough that it should be showing something. New temp sender as well. Same wire which looks old. But again it worked fine before. The thermostat is new, plus when the car is off and I squeeze the upper hose I can hear the coolant sloshing around and hitting the cap. Hose doesnt get firm while running though. Any thoughts why I might not be getting a temp or at least not a very high one? I'll shut the car off and turn the key back on for accessories and the temp will creep up to like 110 - 120.
    Second question is the motor makes a very dull hum sound that comes and goes as it's running. Do the rings make some noise while the engine breaks in and rings seat?
     
  2. John Wright

    John Wright Veteran Member Lifetime Gold Member

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    The sending units are different between a temp light and a temp gauge. Make sure what you have.....the temp light opens to ground when the engine is overheating, the temp gauge will have variable resistance to ground depending on the temperature. Next thing is if you actually have a sending unit for a gauge but it may not have the correct range of resistance over a given temp range.

    not sure what your humming sound is.....
     
  3. CT1275

    CT1275 Member

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    Which part is the ground? See pic, this is what I have. Wire obviously goes to that lead and is disconnected.
     

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  4. gin man

    gin man Veteran Member Gold Member

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    The block is the ground in either case. If you switch clusters from a light to a gauge, the sensor needs to be changed.
     
  5. CT1275

    CT1275 Member

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    I mean on the sender, what's ground? But do you mean put a ground wire to the lead that the sendi,g wire is also connected to? If so I did that and it pegged. Looking like wrong sender.
     
  6. gin man

    gin man Veteran Member Gold Member

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    When you screw in the sender, the outer part of it completes the ground circuit to the block.
     
  7. CT1275

    CT1275 Member

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    Didnt change the guage, just the sender. Different block.
     
  8. gin man

    gin man Veteran Member Gold Member

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    You need to match the gauge to the sender as mentioned above. The sender you are looking for will be a variable resistor, not an on-off switch as would be used for a light.
     
  9. CT1275

    CT1275 Member

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    Ok. I'll grab a new one and try that. So glad they ask you what you have at the auto parts store... lol. Thanks
     
  10. Bills69

    Bills69 Veteran Member

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    teflon tape on the sender can affect the grounding of the sender
     

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