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Where Is The Oil Sending Unit On The F Head?

Discussion in 'Early CJ5 and CJ6 Tech' started by Mark T., Oct 9, 2016.

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  1. Oct 9, 2016
    Mark T.

    Mark T. Member 2022 Sponsor 2020 Sponsor

    Gilbert, AZ
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    Alright my wife says sometimes I am dumb as a box of rocks, and I might be this time too but after trying to find it in the FSM I have or follow the wire diagrams and looking all over the engine, (I think it should be on the lower drivers side) I can't find where it should be. Maybe a PO plugged it or something. Can anyone point me to where this mystery part should be?

    F4-134, CJ5, 1959

    Thanks for the help!
     
  2. Oct 9, 2016
    3b a runnin

    3b a runnin Active Member 2021 Sponsor 2020 Sponsor

    virginia
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    On my 55 3B, it is on the drivers side. low on the block, back near the bellhousing. there's 2 outlets. top one is for the oil tube that feeds the head, bottom is for a hose that feeds the mechanical gauge. The 59 may have had a electric oil sender, but I dought it.
     
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  3. Oct 9, 2016
    mickeykelley

    mickeykelley Well-Known Member

    Republic of Texas
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    My 58 has a an electrical. Drivers side low as I recall. Other side of block is water temp. Pics below.

    Follow oil line down and you'll see the electrical connection.
    image.jpg
    This is water temp. Look by coil in the pic.
    image.jpg
     
    Last edited: Oct 9, 2016
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  4. Oct 9, 2016
    PeteL

    PeteL If it wasn't for physics, and law enforcement... 2022 Sponsor 2021 Sponsor 2020 Sponsor

    Hills of NH
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    Above pics are correct.
     
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  5. Oct 9, 2016
    Mark T.

    Mark T. Member 2022 Sponsor 2020 Sponsor

    Gilbert, AZ
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    OK that really helps. Mine has a steel "return line" coming out of that bottom port that feeds up along side the other line and around to the from where the timing cover goes. I think this may have been some sort of MOD by a PO. I think that timing cover port should go to the bottom of the oil filter unless I am mistaken.
    Thanks for the help and pictures on this one. This rebuild/restore is made a lot more fun because people like you help out. Thanks!
     
  6. Oct 10, 2016
    PeteL

    PeteL If it wasn't for physics, and law enforcement... 2022 Sponsor 2021 Sponsor 2020 Sponsor

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    Correct.
     
  7. Oct 16, 2016
    Mark T.

    Mark T. Member 2022 Sponsor 2020 Sponsor

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    Got around to getting photobucket up and going. Here is what I had in the oil sender slot.

    [​IMG]
    [​IMG]
     
  8. Oct 17, 2016
    PeteL

    PeteL If it wasn't for physics, and law enforcement... 2022 Sponsor 2021 Sponsor 2020 Sponsor

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    Where does the lower pressure line go to?
    It looks similar to the M38A1 set-up where the electric sending unit is mounted remotely, on the rear right-hand side of the block (where a Cj5 usually has the coil mounted).
     
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  9. Oct 17, 2016
    mickeykelley

    mickeykelley Well-Known Member

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    Follow my pics above. One line to up behind the head and the other is sending unit. The lines in and out of oil filter canister goes from right above the fuel pump to the canister and then the canister to back in top of timing chain cover. Not at jeep as on trip but I'll see if I have a pic on file.
     
  10. Oct 17, 2016
    PeteL

    PeteL If it wasn't for physics, and law enforcement... 2022 Sponsor 2021 Sponsor 2020 Sponsor

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    Thanks, however my curiousity was about Mark T's pic. But re-reading his original post, I realize it is the "return" line he references. (I get so confused these days… )

    I would be concerned about low oil pressure unless that bottom 'return' line has a calibrated restriction somewhere. IIRC it was .050" in the oil filter cannister.
     
    Last edited: Oct 17, 2016
  11. Oct 17, 2016
    Mark T.

    Mark T. Member 2022 Sponsor 2020 Sponsor

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    I guess the top line is what you referenced and it goes straight up into the back of the cylinder head. I'll find a pic when I get home and post.
     
  12. Oct 17, 2016
    Mark T.

    Mark T. Member 2022 Sponsor 2020 Sponsor

    Gilbert, AZ
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    [​IMG]
     
  13. Oct 17, 2016
    mickeykelley

    mickeykelley Well-Known Member

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    Here is the line going to the oil filter canister. It's the black line you see behind the fuel pump. In the pic it's right above the hose clamp in the upper right of the pic. The T line is actually above it and is the PCV and vaccume lines.
    image.jpg
     
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  14. Oct 22, 2016
    eti engineer

    eti engineer Member

    Great Central...
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    I have a very thin copper line, which I assume is the return from the head to the oil pan. I notice that the same line in the pix above is much larger. I think the line that I have is the original, but I am leery of the small diameter of the copper line. It looks like it could become plugged too easily. Is there any issue with replacing this line with a larger one?
     
  15. Oct 22, 2016
    PeteL

    PeteL If it wasn't for physics, and law enforcement... 2022 Sponsor 2021 Sponsor 2020 Sponsor

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    Au Contraire… If you refer to the line at the rear top surface of the head, it sends pressurized and filtered oil from the crankshaft feed gallery to the rockers, and I believe the OEM is steel not copper. No reason it should get plugged, and return oil should drain down through the pushrod passages in the head.
     
  16. Oct 22, 2016
    mickeykelley

    mickeykelley Well-Known Member

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    Which pic above? The one just above, the bigger line is actually a vacuum line. The one with the T. It's a PCV and vac.
     
  17. Oct 23, 2016
    Mark T.

    Mark T. Member 2022 Sponsor 2020 Sponsor

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    Lower line goes around the block all the way to the front and into the timing cover.
     
  18. Oct 23, 2016
    Howard Eisenhauer

    Howard Eisenhauer Super Moderator Staff Member

    Tantallon, Nova...
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    Silly question- if that line that runs from where your pressure sensor should be goes to the port on the top of your timing cover, where does the output of your oil filter end up?

    H.
     
  19. Oct 23, 2016
    Mark T.

    Mark T. Member 2022 Sponsor 2020 Sponsor

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    It doesn't have one. I bought it that way and am trying to put it back together.
     
  20. Oct 23, 2016
    1960willyscj5

    1960willyscj5 Well-Known Member

    Mesa, Arizona
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    On mine there are two ports at the rear of the block on the drivers side.
    Top on has a steel line that runs up to the back of the head to lubricate the valve train.
    Bottom one is where my mechanical oil pressure gauge is plumbed from.
    There is an oil line that runs from the pump up across the front of the block along with the fuel line and the vacuum line and goes into the top side of the oil filter.
    There is an oil line that goes from the center bottom of the filter canister and goes to the passenger side of the timing gear cover where it squirts directly into the junction spot of the cam gear and the crank gear, lubricating them before returning to the pan to be sucked up by the pump again.
     
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