Tight fit: New Oil Pressure Sending Unit | FerrariChat
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Tight fit: New Oil Pressure Sending Unit

Discussion in 'Mondial' started by ZekeD, Oct 27, 2025.

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  1. ZekeD

    ZekeD Karting
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    Zeke Duge
    #1 ZekeD, Oct 27, 2025
    My '85 QV needs a new oil pressure sender. Removing the old one was a pain. It would spin 3/4 turn and then get tight (coming off). My new (very expensive) sending unit does the same thing going on. I am fairly sure that it is not cross-threaded, and I got several turns before the 3/4 stall. I have not gotten a wrench on the hex bolt (too many pipes) and don't want to put torque on the sender. Has anyone experienced this "ok-tight-ok-tight problem? Any suggestions?

    Thanks
    Zeke (Oregon)
     
  2. theunissenguido

    theunissenguido F1 Rookie
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    #2 theunissenguido, Oct 28, 2025
    I would try to re-thread the threads in the engine block with a thread reamer if you can find one with the same size and screw thread.
     
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  3. Steve Magnusson

    Steve Magnusson Two Time F1 World Champ
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    #3 Steve Magnusson, Oct 28, 2025
    That's the problem -- better to remove the oil filter mount (item 19) from the engine block and replace the gasket (item 22) so that the sender can be removed/replaced on the bench (with a wrench) rather than apply any torque to the sender outer case:

    https://www.ferrariparts.co.uk/diagram/ferrari/308-quattrovalvole-usa/017-lubrication-system

    IIRC, others have done some crow's foot wrench gymnastics...
     
  4. ZekeD

    ZekeD Karting
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    #4 ZekeD, Oct 28, 2025
    Thanks Steve. It would take a very thin C-Foot (I tried) and Giudo suggested chasing the threads, but I dont want any metal in the oil. Looks like removing the mount is the right way to go.
     
  5. Steve Magnusson

    Steve Magnusson Two Time F1 World Champ
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    #5 Steve Magnusson, Oct 28, 2025
    Yes, I don't know how to find the thread easily, but, IIRC, it took some serious grinding, in many directions, to get the C-foot wrench to be able to work (hence the "gymnastics" ;)).
     
  6. ZekeD

    ZekeD Karting
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    #6 ZekeD, Oct 28, 2025
    Snap-on makes a thin variety, but I dont have the right size (7/8 SAE would work). Even then, Im not so sure. Gaskets will be here Friday.
     
  7. hnichols

    hnichols Karting

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    Hugh Nicholson
    #7 hnichols, Oct 30, 2025 at 1:12 PM
    Yeah, definitely remove the three nuts attaching the housing to the engine. You have to move a hose or two to the side, but it's not difficult. Trying to remove that sender by grinding a wrench is way too much trouble. You can also easily cut your own gasket if you're in a pinch.
    I did this last year, and my new, and expensive, oil sender has stopped working. That's another question.
     
  8. ZekeD

    ZekeD Karting
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    #8 ZekeD, Oct 30, 2025 at 9:10 PM
    yeah, I hope this sender is bulletproof...... We will see
     

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