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Oil pressure Sending unit

Discussion in 'Engines' started by MBevins, Aug 9, 2024.

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  1. MBevins, Aug 9, 2024
    #1
    MBevins

    MBevins Senior Member

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    My starboard oil pressure gauge started acting wonky.
    First thing was swapping the gauge with the port side.
    Sure enough it's not the gauge, so we'll be checking the sender in the morning when I'm doing my checks.

    I'm not worried about lack of pressure, the gauge is pinning high and flopping around so I suspect connection or actual unit.

    Are these things matched to gauge mfg. or generic?

    Engine is a DD 6-71.
    Also I'm assuming it's somewhere around the oil filter.
    Any information would be gratefully accepted.
  2. Capt Ralph, Aug 9, 2024
    #2
    Capt Ralph

    Capt Ralph Senior Member

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    Stewart-Warner or VDO?
    If you touch the sender lead to ground, the gauge will go high for SW, The gauge will go down for standard* VDO.
    Detroits were ordered with either sender.

    Sounds more like a bad connection or chafe on the lead wire.

    Always better to read a number off of the sender if you can.
    *later VDO will sell SW compatible senders and gauges.
  3. MBevins, Aug 9, 2024
    #3
    MBevins

    MBevins Senior Member

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    That's what I'm hoping it's just a bad connection or short. The gauge bounces to high so I'm assuming it's SW.
    When I find the actual sender I'll look for any numbers.
  4. LM Viking, Aug 9, 2024
    #4
    LM Viking

    LM Viking Member

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    My gauges are VDO. Make sure you get the right sender and for a single station.

    I had a trawler that always read high without thermostats in. Finally after contacting the gauge manufacturer I found out I had single station sender on a dual station boat. The right sender fixed the problem 2 diesel mechanics could not figure out.
  5. Capt Ralph, Aug 9, 2024
    #5
    Capt Ralph

    Capt Ralph Senior Member

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    It will drive you to drink.
    In my case,,,, More...o_Oo_O

    But brothers, stay calm, logic (sobriety) does come to us occasionally and all is well.
    It has been one of those weeks...:(
  6. MBevins, Aug 9, 2024
    #6
    MBevins

    MBevins Senior Member

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    2 things.....hope you're well
    And I'll take a picture as I closed up the helm. .... please hold.
  7. MBevins, Aug 9, 2024
    #7
    MBevins

    MBevins Senior Member

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    No picture needed, zoomed in, the face says VDO.
  8. LM Viking, Aug 9, 2024
    #8
    LM Viking

    LM Viking Member

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    I looked on used 1987 and pics show same at helm. I’m sure they used the same in that vintage.
    I am well. Actually in the North Channel right now.
  9. Capt Ralph, Aug 9, 2024
    #9
    Capt Ralph

    Capt Ralph Senior Member

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    Wish I was back on our boat. Just found our house second bathroom head, NEW service valve leaking. The NEW freaking valve.
    Yep, A heck of a week and not over yet.
    Bothers, stay on your boats/ships. This land stuff is driving me bonkers.
  10. MBevins, Aug 10, 2024
    #10
    MBevins

    MBevins Senior Member

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    Problem solved, got lucky, the retaining nut on the sensor has come loose.
  11. MBevins, Aug 10, 2024
    #11
    MBevins

    MBevins Senior Member

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    But this brings up another question that I'm thinking about. In all my years of owning this boat I should know.
    The oil pump on the 6-71... internal or external?
  12. Capt Ralph, Aug 10, 2024
    #12
    Capt Ralph

    Capt Ralph Senior Member

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    Great news.
  13. Capt Ralph, Aug 10, 2024
    #13
    Capt Ralph

    Capt Ralph Senior Member

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    The in-line 71 use an gear driven oil pump. Accessed by removing the oil pan.
    Hope this helps.

    Are you having issue or just wondering?
  14. MBevins, Aug 10, 2024
    #14
    MBevins

    MBevins Senior Member

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    I was just wondering.
    That means raising the engine if you have an issue.
    But I suspect if you have an oil pump issue, by the time you catch it, the engine's smoked anyway.
  15. LM Viking, Aug 10, 2024
    #15
    LM Viking

    LM Viking Member

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    Good news about the sender. Hopefully if there is a pump issue an alarm will go off but I don’t know if it would be in time to shut engine down.
  16. Capt Ralph, Aug 10, 2024
    #16
    Capt Ralph

    Capt Ralph Senior Member

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    These pumps are direct gear driven from the crank shaft end. Very well built and very reliable.
    There is a pressure regulator and over pressure safety valve before the engines oil filter and cooler.
    IMO, you can sleep very well that you will not have an oil pump issue in your engines.
    chesapeake46 likes this.
  17. Capt Ralph, Aug 10, 2024
    #17
    Capt Ralph

    Capt Ralph Senior Member

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    You probably look at your oil pressure gauge when slowing down to an idle after a good run.
    You noticed around 5psi on your gauges and like I did, freak out after my first couple of runs.
    No worries, good ole CF2 engine oil is flowing well and lubricating all proper.
    In a few minutes of idling around, the PSI comes back up a bit.
    This is normal and has left a few brown spots with novice Detroit owners.
  18. MBevins, Aug 10, 2024
    #18
    MBevins

    MBevins Senior Member

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    Trust my first hand knowledge, by the time the alarm sounds you have no pressure. And no engine
  19. MBevins, Aug 10, 2024
    #19
    MBevins

    MBevins Senior Member

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    Yep, but after 23years with these engines, that's pretty normal stuff
  20. LM Viking, Aug 10, 2024
    #20
    LM Viking

    LM Viking Member

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    I hate 1st hand knowledge. It usually comes with a high price tag attached.
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