Wires at alternator melting

Discussion in 'Mk1' started by 0337, Aug 15, 2019.

  1. 0337 Paid Member Paid Member

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    Hi all, I have a 1991, golf gti cabriolet, dx engine and have noticed that the wires coming from battery all the way to the alternator has been slowly melting part of the plastic coating, also the plastic cap on the alternator for the 13mm nut has also melted away. Anybody able to help me on this as to why this is happening. Thanks in advance.
    20190815_135838.jpg 20190815_135858.jpg 20190815_135923.jpg
     
  2. H8V

    h8v New Member

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    It looks that the cable had been passing way, way too much current.
    Is the cable hot now, or is it historic damage?
    If it's happening now, is it when the engine is off or just when it is running?
     
  3. 0337 Paid Member Paid Member

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    From what I can remember is that the wire had previously been as they are (before I got the car) but the plastic cap at back of alternator has only recently been noticed.
     
  4. H8V

    h8v New Member

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    If it doesn't get hot now, it must be historic. Could it be that the insulation became worn through and created a short to earth?

    On ebay you can get "plastic nut covers" to replace the overheated one. It's an M8 nut I think.

    It would be an extremely good idea to cover the damaged cable insulation with some sleeving or at the very least plenty of insulation tape.

    Is the cable damaged right back to the battery? You might consider replacing the whole thing.
     
  5. rubjonny

    rubjonny Administrator Admin

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    I would recommend you replace that cable, its too far gone for my liking. MK3 golf cables are nice, get the full set. MK4 might work even, but I like the MK3 battery terminals.

    only thing is you'll have to modify the blue wire that comes with it, need a ring terminal for alternator D+ and spade to plug into the connector near the battery. If you extract it from the old loom can make a judgement if its worth saving or if you want to just make up a fresh section
     
  6. pigbladder Forum Addict

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    deffo needs replacing ...isnt too hard to make them up out of thicker gauge stuff
     
  7. 0337 Paid Member Paid Member

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    Hi all, ok the wire does need replacing I do have a spare one, but before I change the wires I did a quick check. Started the car and let it run for about 1 to 2 mins and touched the 13mm nut at back, boy was it hot. Is it suppose to get so hot, or is it time for a new alternator?
     
  8. rubjonny

    rubjonny Administrator Admin

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    Try it again with a new.cable, might be down to increased resistance of the knackered.cable
     

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