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Possible explanations of 10 psi loss of oil pressure at cruise

Discussion in 'Technical Discussion' started by motoryachtlover, Jun 27, 2020.

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  1. rtrafford

    rtrafford Senior Member

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    Thank you so much for the explanation. I was trying to wrap my head around his issue and understand the culprit, but I was stuck on that sender versus what I know of, well, Murphy Switches. That micro tube or capillary set up is my experience, a lengthy one on a wide variety of engines.
  2. motoryachtlover

    motoryachtlover Senior Member

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    Sorry I am late to get back to you all. I have photos of the engine room gauges at 1000 RPMs and temp of 170 and the oil pressure on the port is a little over 50 and the starboard a little under 50 (mechanical gauges) I don’t have pictures of idle. The viscosity is 15W40.
  3. mapism

    mapism Senior Member

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    Viscosity is fine, and also 50 psi at 1000 rpm is plenty.
    For your future reference, at idle even a bit less than 30 psi would still be fine.
    You do have a surprisingly high pressure at 2k rpm, but better than the opposite, anyway! :)
  4. rtrafford

    rtrafford Senior Member

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    Consider swapping gauges between engines, see if the issue follows the gauge? Repeat with senders?
  5. Capt J

    Capt J Senior Member

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    In reality, 70 psi at cruise is a NON issue or really anything over 40 psi at 2000 rpms.......I just delivered a yacht with the same engines and at cruise it only made 50-60psi.....
  6. Soulstice

    Soulstice Member

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    I have similar pressures on my MAN’s with about 45 psi at cruise and running 15W40. I wouldn’t worry too much about the pressure you are running at as it sounds pretty normal.
  7. motoryachtlover

    motoryachtlover Senior Member

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    Thanks to all that commented. Much appreciated