1st Gen "How To" Crank Sensor Seal Replacement

Oring.png
On almost every R53 that I’ve seen lately, the crank sensor is weeping at least a little bit of oil. When it is just barely leaking, you will get...
By agranger · Jan 18, 2018 ·
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  1. agranger

    agranger MINI of the Month June 2009
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    #1 agranger, Jan 29, 2012
    Last edited: Jan 29, 2012
  2. Professor

    Professor New Member

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    Glad to see I am not the only one using the ratchet strap method. Just need to be careful though, I have seen people overstress the upper mount this way.

    Good write-up
     
  3. Nathan

    Nathan Founder

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    Thanks for contributing this to the library.
     
  4. Crashton

    Crashton Club Coordinator

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    Nice write up!

    Thanks....
     
  5. Norm03s

    Norm03s New Member

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    Thanks agranger, I will be doing this in the Spring, you have just saved me some time and grief for sure.:Thumbsup::Thumbsup:
     
  6. Mr. Jim

    Mr. Jim Mudshark
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    Nice! Thanks again for another great write up.
     
  7. ScottinBend

    ScottinBend Space Cowboy
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    And another great write-up added to MY library!
     
  8. agranger

    agranger MINI of the Month June 2009
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    Glad you liked it.

    I replaced this sensor o-ring when I did my supercharger oil and oil pan gasket a few months back (that final pic is of my engine w/ the sensor sealed up w/ extra high-temp RTV and a new o-ring. It was easy to do while I had the entire front clip off of the car because nothing was in the way.

    This weekend, I was helping a local club member out, trying to figure out how to squeeze my fat hand in there to do the job when a tech walked by and told me about the ratchet strap trick. Very handy! As soon as I saw how easy it would be with the engine rocked back, I knew that I had to do another MA article.

    Christy has an oil leak. It is either coming from this crank sensor or from the oil pan gasket and we couldnt' figure out which. It was the MINI tech again to the rescue. He recommended doing the crank sensor because it was cheap and easy (much like myself), changing the oil and cleaning up the front of the engine very well. Then at the next oil change, we can assess if it will need a new oil pan gasket.
     
  9. agranger

    agranger MINI of the Month June 2009
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    Very good point. I just added a note to the article. Thanks!
     
  10. jeffster06

    jeffster06 Active Member

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    Nice write up I changed mine while replacing the water pump last year. One thing I was wondering why drain the oil when changing the o ring? When I did mine the oil didn't leak out. I wouldnt think the level sits high enough to come out of the hole. Is it because your tilting the motor?
     
  11. agranger

    agranger MINI of the Month June 2009
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    #11 agranger, Jan 31, 2012
    Last edited: Jan 31, 2012
    You know, that's a good point. My friend was in for an oil change, so we did this in the middle of the oil change for safety. I just assumed that it could be an issue, but that sensor is fairly high up there... no way that it's submerged in oil all of the time. In fact, the sensor is above the point where the dipstick guide tube enters the block and that is above the point where the dipstick measures the top of the oil in the sump, so leaking oil out of the sensor hole shouldn't be an issue at all, even with the few inches that the engine is rocking.

    That's a handy thing to know. I wouldn't have said to do the seal replacement without draining the oil as I've never done it that way myself (despite what my theory says) and I wouldn't want to lead anyone down the path to a mess like that might cause, but with your actual experience to back up the theory, I made an update to the article. Thanks!
     
  12. MarkK

    MarkK New Member

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    I started to do this repair by this method. Being my first time in that area, and with a significant amount of grime in there, I decided to put my car into 'service mode', which was more work, but not difficult. I would say that if this is your first time doing this job, I would recommend the 'service mode' way of going about it. Thanks for all the great pictures on this repair. It was all very helpful!
     
  13. Minidave

    Minidave Well-Known Member
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    I'd be willing to bet that 99.9% of the oil pan gaskets that have been changed on 1st gen cars were not needed, the oil was coming from the crank sensor and following the lip of the pan.

    You will not spill any oil out of the crank sensor hole, it's WAY above the oil level, even if you tip the engine.

    I've replaced a bunch of these o-rings over the years, and not one car has needed a pan gasket after drying up the oil coming from the sensor.
     
  14. MarkK

    MarkK New Member

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    The 10mm bolt that secures the crankshaft position sensor... is there a torque setting for that?

    I did utilize the extra space and view by tipping the engine back using this method, even though I put the car in service mode. I have big hands, and no hoist, so it was helpful.

    Also, it was good to get the power steering cooling fan off and see how full of muck it was... it is very easy to take off, and it needed a good cleaning.
     
  15. Crashton

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    10mm bolts do not need much torque. Clean bolt & use some 242 loctite.
     
  16. agranger

    agranger MINI of the Month June 2009
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    very little torque... the sensor is plastic. no need to crush it... just keep it snug.
     
  17. 1momini

    1momini New Member

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    I did this while I was replacing oil pan. It had been leaking a lot. I noticed 2 rough spots inside the hole where the sensor goes. They were almost straight lines from outside edge to inside edge of the hole. They were almost perfectly perpendicular to each other on right and left side of the hole. I almost thought it was intentionally there. But I took a scotch pad and smoothed it up. Might want to run your finger in that hole.
     
  18. agranger

    agranger MINI of the Month June 2009
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    Must... not... post... reply! (said in my best James T. Kirk voice)
     
  19. R53SME

    R53SME New Member

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    hey guys! Newbie here. i saw the write up for the crank sensor O-ring replacement with the ratchet strap.

    now when i remove the two bolts from the bottom mounts will that pretty much have all the tension on the upper mounts? is that ok?

    and where exactly should i attach the ratchet mounts?

    thanks in advance!
     
  20. agranger

    agranger MINI of the Month June 2009
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    See "Figure 4" in the article linked on the first post. One end attaches to the bottom of the engine, near the oil drain bolt, probably where the lower engine mount (dog bone) is. The rear strap goes anywhere solid near the back of the car... looks like I chose a small square bracket that is right under the exhaust pipe. Just don't pinch a brake line or anything like that.

    Holding the engine weight on the upper engine mounts will be fine. I wouldn't drive it like that, but it will be fine for the purposes of the repair.
     

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