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Man D2848 LE403 Oil Pressure Senders

Discussion in 'Engines' started by butch w, Jul 8, 2023.

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  1. butch w

    butch w Member

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    Two part questions, bit of a read. First question is where is the best place to source sending units or pressure switch etc. Mechanical engines analog gauges.

    Port engine has always read half the oil pressure of what starboard reads. I do have the engine room gauges along with the helm gauges. ( no alarms ever) All of the other gauges are reading within normal ranges of each other.

    Port is typically 40 psi max while starboard will go as high as 85 psi and when on long runs at 1900-2000 starboard is around 50-60 holding steady port is reading 20-30 holding steady. (I have tried a different gauge same results)

    I am not sure where the oil pressure sending unit or pressure switch etc. is mounted on these motors. The first thing I want to do is make sure all connections are tight and clean. I also want to verify that they are the correct sensors as its been said there are two different ones for single or dual helm.

    I have read all of the manuals I have on these engines several times and I don't see anything about the oil pressure sending units etc. Any and all suggestions are welcomed as you all have been an outstanding help in the past

    Thanks all
  2. Capt Ralph

    Capt Ralph Senior Member

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    Oil pressure reading low on the MAN display or SW (Stewart Warner) dash gauges?
    MAN senders are from DanFoss.
    Sometimes
    you can get the DF part number off of the sender, google it and save some bux.
    SW senders and gauges from NAPA.

    I still order my MAN parts from these kids.
    They probably sold and installed your engine.

    https://www.performancediesel.com
  3. butch w

    butch w Member

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    The gauges are analog Vdo both on helm and engine room, the boat is a 2001 no digital output on the gauges and the alarm/warning lights are non digital also
    oil guage.jpg

    alarm warnings.jpg
  4. Capt Ralph

    Capt Ralph Senior Member

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    Here is the problem with VDO and DIY;
    SW works one way, low resistances to high makes their gauges go up.
    VDO by standard works bass ackwards, high resistances to low makes their gauges go up.
    Oh, But here is the rub; VDO also makes SW compatible senders and gauges.

    There are different ways to find witch way your VDO is set up;
    Call Viking and ask what they used.
    Find a part number on the gauge and search from that.
    Call me back for the red-neck process.

    Now that I'm typing, I think I have your problem figured out.
    Just ran into this problem for another guy.
    You typed a VDO gauge in the ER and the helm??
    Dual gauges on the same sender is possible,, if you use a sender for two gauges.
    Or, a dual gauge sender will miss read on a single gauge.
    For either VDO or SW.

    While your looking for gauge part numbers, Let me try to find the sender locations for your LE403s.
    I'm on my boat but back in the compound tomorrow.
    If our bud in Sardinia is watching, he may remember where they are from the top of his head.

    Have you looked around the oil coolers for any wire connects yet?
    My first guess where they are.
    Last edited: Jul 8, 2023
  5. butch w

    butch w Member

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    Thanks for your help, as you all have probably figured out I am new to diesel powered boats, and it's been a bit intimidating because of all the systems and big engines, wiring, transmissions etc.

    But I have always done my own maintenance on my gas outboard powered boats ( timing belts, vst filters, tensioners etc) so fairly involved outboard mechanics. And never intimidated by a boat I can put on the trailer or lift to work on.

    I am gaining more confidence and knowledge as I go and also thanks to this forum. I have not seen the locations yet and have been cleaning like crazy under and around engines and going over everything making sure all connections are tight and proper etc , hoses, wires etc but just not certain on the sensors. will search more tomorrow.

    eng rm.jpg
    eroom.jpg
  6. butch w

    butch w Member

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    picture of the boat
    gibson .jpg
    chesapeake46 likes this.
  7. Capt Ralph

    Capt Ralph Senior Member

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    port eng.jpg
    Peek under the right exhaust manifold. Oil cooler and oil pressure senders should be there.
    Or, follow the hoses from the oil filters to where they attache to the engine. Should be same place.

    Weighing anchor shortly. Looks like another nice & hot day on the St Johns river.
  8. butch w

    butch w Member

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    Was at the boat today and scoured all under and around the engines. Followed (on the port plant) where the oil lines meet the engine and that is right under where your red arrow is, nothing in that area. could not find any sensors on either engine.

    I assume if they are down low on the engine then they are on each outward side. Port side is the one I am having what I call low readings.

    I assume that the pressure is more than 10-15psi idle and 20-30 loaded. I do not get any alarms and they function via the test button etc. I would think a 20 psi would throw an alarm, could this motor just have that low of pressure maybe?

    thanks all
  9. Capt Ralph

    Capt Ralph Senior Member

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    There are not many wires that go into a LE403 mechanical block.
    These wires and plugs are probably covered with lots of engine paint.
    The oil pump is to the flywheel/rear of the engine.
    The Pressure relief valve is inside the pan, behind the oil cooler, where the oil filters or remote hoses are mounted.
    Somewhere around there is the pressure sender. Probably more hiden by the exhaust manifold.
    Can't be many wires on that side.
    The starter and heater box (if equipment) are on the other side.
    My manual gives me the resistance values for different pressure readings but not a picture of where that dam sender is at.
  10. Capt Ralph

    Capt Ralph Senior Member

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    I recall only 2 sets of wires down there. Oil pressure and Pyro coupler.
    two wires.jpg
  11. butch w

    butch w Member

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    What readings of oil pressure are you all seeing on your 2848's at idle and cruise rpms typically ? And what is the Pyro coupler ?
  12. Lunderic

    Lunderic Member

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    I second what CR already mentioned, the gauge that's reading half is designed for single station application. Since your engine room remote gauges are reading normal the sender is working fine. BTW I have 2840's and they indicate 30-40 at idle and 60-80 at cruise warmed up. Readings are much higher cold.
  13. Capt Ralph

    Capt Ralph Senior Member

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    Hello Lunderic
    Do you have a manual or picture showing exactly where your pressure sender is located?
    My thin manual collection does not show anything and my memory has lost it's slower brain cells (all are slow these days).
  14. mapism

    mapism Senior Member

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    I can second what Lunderic said ref. the pressure readings in my boat, powered by the very same engines as per thread title.
    And I would second also CR question to Lunderic (or anyone else, for that matter) about any manual showing the sender location.
    In fact, I'm now onboard and I just tried to locate the bloody thing in flesh, with no success!
    I was also thinking to find it in the area mentioned by CR, but there's nothing down there.
    BTW, in my boat I've got the plain vanilla oil filters directly mounted with no remote kit, so I don't think anyone ever fiddled with the sender.
    Besides, I have manuals showing a drawing of it, as well as its part number, but not the location, aaaarumph!
  15. butch w

    butch w Member

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    I have actually disconnected the engine room oil pressure gauge a while back because when that was hooked up I was getting 10 psi across the board lower reads on the helm and the engine room one was not even really registering if I recall correctly.

    I am assuming I have the wrong sending unit so far.....but really would like to be able to find it. it could be as simple as a dirty connection but again need to find it :)
  16. ChiTown

    ChiTown Member

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    I have a similar issue with my port temp gauge/sender, more an intermittent connection issue. It seems the gauge panel sensors are different from the MAN system (such as it is in these completely mechanical units). The Manuals give zero info on location, pretty poor.
  17. Capt Ralph

    Capt Ralph Senior Member

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    Trying to remember or find a past customers mechanical MAN near me.
    Last mechanical V12 I worked on sold and left town.

    Time for a call or e-mail to Texas with engine serial number.
    https://www.performancediesel.com
  18. Lunderic

    Lunderic Member

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    There are two senders just forward and below the oil filter housings. There is a third in the rear (I believe that’s oil temperature sender for remote panel)
    IMG_9550.jpeg IMG_9551.jpeg IMG_9551.jpeg
  19. Capt Ralph

    Capt Ralph Senior Member

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    That is where they were on that mechanical V12 I used to work on.
    However, the OP has remote oil filters.

    I wonder if the senders were moved with the filter bases. Never noticed that before.
  20. Capt Ralph

    Capt Ralph Senior Member

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    AND, you have an oil line/hose coming off of the filter base assembly,,, To a remote mechanical pressure gauge or to the turbo?
    That could offer another way to find the senders, follow the turbo oil supply hose back to the engine. Sometimes mounted on the block at the same place.