Perkins Engine Sensors (Sending Units)

  • March 14, 2012 3:58 PM
    Message # 859010
    I'm finishing up my Perkins 4.108 reconditioning and getting it ready to stick back in the boat. None of the sending units (Oil Pressure, Water Temp, etc.) were hooked up before I removed the motor, and I can't seem to locate any good references that indicate which does what.

    I find what appear to be 4 sensors, numbered 1-4 in the attached photos. Can someone please let me know for sure what each of them is for? 

    My guess would be:
    1. Oil pressure switch
    2. Oil pressure sender
    3. Water temp sender
    4. Water temp alarm



    Last modified: March 15, 2012 5:07 PM | Anonymous member
  • March 16, 2012 4:55 PM
    Reply # 861050 on 859010
    So, apparently either...

    1. Nobody owns a Perkins 4.108
    2. Their engine has no gauges
    3. Nobody logs on to the forum any more

    Whatever the case, I discovered that my best guess was indeed correct, as confirmed by the folks at Tran-Atlantic Diesel.

    Just thought the info might help someone else ;-)
  • March 18, 2012 4:51 PM
    Reply # 862459 on 859010
    Deleted user

    Jack, could be confusion?  The devices on my Perkins are not in the same location even do not look exactly the same.  Questions for you - or anyone else - what is that dip stick to the left of item #3?  Hope I have not gone for a long time not checking something. Also, which item is the battery regulator exciter, oil switch or ignition switch?  Does it matter?


  • March 18, 2012 6:20 PM
    Reply # 862532 on 859010

    There were several variations in senders and other items through the years, in some cases dependent upon the cooling system configuration and year of manufacture. My motor is a 1987 4.108 and I have a Bowman Heat Exchanger mounted lengthwise on the left side of the engine. Some had their cooling systems mounted horizontally across the front of the engine.

    The photo that shows #3 is the left rear of the engine. The dip stick to which you refer is the oil dip stick. Surely you've been checking this...where is yours located?

    I believe your reference to "oil switch" (that triggers the low pressure alarm) is my item #1. Item #2 is the oil pressure sender that attaches to the oil pressure gauge.

    I've attached some photos of my engine that's about ready to go back in as a reference for possible differences.

    Last modified: April 16, 2015 5:49 PM | Anonymous member
  • March 19, 2012 10:53 PM
    Reply # 863751 on 859010
    Deleted user
    O.K. dip stick.  Mine is on the same side but faces forward.  Yea I've checked it - a lot.
  • March 20, 2012 10:03 PM
    Reply # 864698 on 863751
    Gerald Astrella wrote:O.K. dip stick.  Mine is on the same side but faces forward.  Yea I've checked it - a lot.

    I'm sure you do, Gerald. It's amazing how many minor variations there were in these engines.  (Did you just call me a dip stick?)
  • March 20, 2012 10:56 PM
    Reply # 864712 on 859010
    Deleted user

    Oops, I guess this exemplifys the importance of punctuation.   I'm still chuckling. Thanks you made my day.


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