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Alternator Stud Sealant issue

Discussion in '100-Series Cruisers' started by RMPIPE, Feb 17, 2017.

  1. RMPIPE

    RMPIPE

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    I recently replaced my tensioner assembly. The nut on the top stud of the alternator was corroded onto the stud and when attempting to remove the nut, the entire stud backed out. I was able to get the nut off the stud and everything cleaned up, but now I can not get the stud to seal into the water jacket and I have coolant leaking when the engine is under pressure.

    I tried red loctite first, that didn't work and it still leaked heavily. Then I tried Mr. T's FIPG after speaking to a Toyota Mech, and that did better but it's still leaking quite a bit. Threads and stud were cleaned between each application. Coolant was drained also between each.

    Any suggestions?
     
  2. 2001LC

    2001LC

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    I'm not sure what stud you're taking about. Do you have a picture?
     
  3. RMPIPE

    RMPIPE

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    Sorry, I do not have a photo. On a 99 there is a stud that the alternator slides on for the top, and a bolt that goes through the bottom of the alternator. It's the stud at the top. When replacing the tensioner assembly, the PS pump has to be moved or the pulley removed to slide the alternator off of this stud.

    Hope this helps.
     
  4. jLB

    jLB Curmudgeon in training

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    Something like this?

    upload_2017-2-17_12-15-32.png
     
  5. PLROD

    PLROD SILVER Star

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  6. 2001LC

    2001LC

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    There are some high temp sealant or adhesive out there that should handle coolant. But really it a temp fix. The stud may not have been OEM and some ran in to deep, damaging the component it's in, or possible it cracked the casing. I just can't picture what component it's goes into. If it's the water pump, replace it, if it's the block well that's F'd up.
     
  7. RMPIPE

    RMPIPE

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    This is not my engine, but the stud in the red box with the arrow is the culprit.
    2UZTimed.jpg
     
  8. RMPIPE

    RMPIPE

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    Also wondering, does anyone have the torque specs for that stud?
     
  9. 2001LC

    2001LC

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    29ft-lbf for the alternator nut & bolt, I've not seen one for the stud.

    Drive belt tensioner x Cylinder block is 12ft.-lbf.

    Are you sure leak isn't from somewhere else. There are many places in that area where coolant leaks can develop (water bypass joint, cross over pipe, thermostats housing, hoses, water pump, head gasket,...)!



    I hope I'm wrong but if leak is from that stud hole, you may have a cracked block. Possible @ponytl or someone can shed some light here?
    2UZ-fe 2.jpg
     
    Last edited: Feb 20, 2017
  10. RMPIPE

    RMPIPE

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    Thanks 2001lc for the help!

    I've been working on this further today and found that I didn't tighten two of the bolts on the tensioner assembly all the way :censor::bang:. I also haven't been able to find more evidence of fluid leaking from the alternator stud which leads me to believe that the most recent leaking was related to the other bolts as that's where it appears fluid is present. No leaks in Thermostat housing, crossover pipe, or any hoses in the area.

    I know that there was some major leaking from the stud before the last attempt to seal using Toyota FIPG because the leak was severely less after I re-sealed the stud.

    After a brief drive since tightening the loose bolts, i'm not seeing any more leaking. I'll monitor this over the next day or so of driving and see if those were the culprit.

    Once again, thanks for the help.
     
    Last edited: Feb 18, 2017
  11. 2001LC

    2001LC

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    Check your coolant level each morning at reservoir to make sure no lose, once burped. With engine cold & outside temp the same, level should be the same each morning.

    Self burping: With engine cold (8 hours) top radiator and fill reservoir to low (cold) line. This may take two or three hot & cold engine cycles.

    Make sure to keep you're eye on the weep hole for leaks:
    121.JPG
     
  12. RMPIPE

    RMPIPE

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    I got it all refilled yesterday and drove it for a bit. The leak is still there and pretty bad. I'll take the belt and alternator off tomorrow and run it 'till it pressurizes to see if I can 100% confirm the leak is still coming from that stud and not somewhere else. I'll keep you updated.
     
  13. 2001LC

    2001LC

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    Looking at the FSM; it appears the bolt holding tensioner goes into the block, and the two nuts go on studs. All have a torque of 12ft.-lbf. One stud goes into water pump, the other comes through from block. Over tightening the stud on water pump or nuts on either stud could possible cracked water pump housing.

    Many places for leak in this area, but most should not have been affected by drive belt tensioner replacement job.

    Good luck!
     
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