Forums General Discussion Ghost in my temperature alarm?

This topic contains 7 replies, has 6 voices, and was last updated by  RichCarter 2 years, 3 months ago.

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  • #223050

    Ryan Doyle
    Participant

    Hey All,

    Curious if anyone here has any insight to my issue. I have an original W58. Rebuilt about 3000 hours ago. Motor runs just fine. Plenty of power, no smoking, starts right up. No issues except this one:

    I have a high temp alarm on the engine that supposedly (a mechanic told me) is set to ring at 240F. It now rings without fail after almost exactly 40 minutes of running.

    However, my temperature gauge only reads about 179F and with my infrared thermometer the highest temperature I can read on the top of the engine is 175F. Of course, exhaust headers read hotter, but the thermostat housing and the block is all under 175. The engine doesn’t seem to actually be running hot.

    To make things even weirder, this is now the second high temp alarm this mechanic has installed (after we thought the first one was faulty because of the same seemingly premature ringing.)

    The one thing I’m wondering is if it’s actually a 200F alarm instead of a 240F and my mechanic is mistaken. It seems at least theoretically possible that while the outside of the sensor housing is only reading 175F that the inside could be 200F? Could I have another bad temp sensor? Or am I missing something?

    Thanks very much in advance for any help.

    Ryan

    Attachments:
    1. IMG_9869.jpg

  • #223052

    typhoontye
    Participant

    I installed an aftermarket high temp sensor at the thermostat housing after the one the PO installed became disbonded from the extruded exhaust manifold. I failed to write down the brand, etc, but could find it if you want. I’m happy with the sensor except that it is set to go off at 200 degrees F, if memory serves. I still have engine overheat issues, and when I occasionally push power up to 2200 or over to make a bridge, or whatever, the temp will get to 200 and the alarm goes off. Not so bad if it would turn off once I’m back at 180. But the reset is around 160 degrees. So I have a SPDT switch in series so I can turn the alarm off. Of course then I have to watch the temp gauge like a hawk. Not ideal.

    David
    Blue Moon

  • #223053

    Ryan Doyle
    Participant

    Hi David,

    Thanks so much. I wonder if my switch has the same reset at 160, because once the buzzer starts it does not stop. Maybe a SPDT switch is in order if I can’t get to the bottom of this.

    Just odd because the engine doesn’t actually seem to be running above 180 according to my temp gauge and infrared thermometer.

    Cheers,
    Ryan

    • This reply was modified 2 years, 4 months ago by  Ryan Doyle.
  • #223055

    typhoontye
    Participant

    I think it unlikely that the engine is running at 200 degrees plus if you are measuring 180 at the thermostat housing with the infrared heat gun. I am assuming your overheat sensor is at the thermostat housing? You may want to read the thread ‘Hot W58’, which contains some data concerning engine temps that were recorded at the cockpit gauge and simultaneously with an infrared heat gun. Towards the bottom of the thread you can find actual recorded temps from Blue Moon and Discoverie.

    I suspect you may have another bad sensor or the installation location may not be optimal? Maybe need to go to a different brand OH detector? Or perhaps the electrical connections may not be correct?

    David

  • #223056

    Seawater
    Participant

    Madness has the oil low pressure alarm sharing the same circuitry as the overheat alarm. Thus was done by Pearson, as it is shown that way in the owners manual. Perhaps your oil is getting thin after 45 minutes of operation?

    Also, if you are having heat issues, bypass the V drive. Did it a decade ago, engine runs cooler in extreme circumstances, V drive never gets over 140. I think the water resistance in the V drive use v to hobble the cooling system when running very hard, but not now. But I never really had a significant issue, it just crept up 15 or 20 degrees.

    Good luck.

  • #223160

    Madness
    Participant
    My alarm is also wired to the low oil temp. They share the same circuit. 
    Sent from my Verizon 4G LTE smartphone

    ——– Original message ——–

    Attachments:
    1. 270022213471606696.pdf

    2. 4799812803392710856.jpg

  • #223163

    unabated
    Participant
    Do either of you have a part number for the sensor? 
    Alan 

    Attachments:
    1. 270022213471606696.pdf

    2. 4799812803392710856.jpg

  • #223166

    RichCarter
    Participant

    David

    Your thermostat is probably set to open at 195 deg.  Running a bit higher than that is expected.  Your engine should be running around 220 deg under load. 

     

    Rich

     

    Attachments:
    1. 270022213471606696.pdf

    2. 4799812803392710856.jpg

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