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    Thread: Mystery: thought bad starter, but flywheel turns and not crankshaft?

    1. Junior Member
      Join Date
      Jul 22nd, 2017
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      81
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      Tigs, Jettas, GTIs, CC
      09-12-2019 11:19 PM #1
      1.8T manual transmission, 180k miles and starter spins but won't fire.

      Timing belt is intact. When I turn the crankshaft with a wrench the cam also rotates over many revolutions and no rough spots or contact with valves vs. pistons.

      Replaced starter figuring bad solenoid, but no improvement. Removed peep hole plug and see that flywheel turns fine when starter engages. Dang.

      How can flywheel turn but not the crank?

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    3. Member vdubbugman53's Avatar
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      Nov 7th, 2006
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      Denver, CO
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      2013 Turbo Beetle, 2003 New Beetle
      09-13-2019 04:37 AM #2
      Roll the motor to TDC. Check the cam mark and the mark on the FW. If you slipped the belt and the starter has turned the motor over you already bent valves and would not feel them any more.

      If those line up crank her and pull a plug and see if she smells like fuel.

      Have you put a vag com on her?

      Sent from my Pixel XL using Tapatalk

    4. 09-13-2019 11:22 AM #3
      So the flywheel turns but not the crank? Sounds like a broken flywheel or flywheel bolts.

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    6. Junior Member
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      Jul 22nd, 2017
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      Tigs, Jettas, GTIs, CC
      09-23-2019 10:30 PM #4
      So the belt teeth are stripped at the crank. Best I can figure is that when I turned the crank from under the car and my assistant told me the cam was turning, either there were just enough teeth still grabbing the crank to turn the cam briefly, or the tension itself was enough to turn it. And though it had slipped, maybe it happened to be back in time enough to crank the motor without hitting the valves again.

      I should have been more thorough.

      When I put the new starter in, maybe things turned until the section of the belt with the missing teeth got to the crank. Or the starter just turned the crank and ripped off the teeth at that point.

      So I got the new belt on and of course, bad news. No compression on at least two of the cylinders. So I'm off to the next little adventure pulling the head and replacing some bent valves.

      180k and the old belt is a Gates "racing" unit put on at an unknown interval by previous owner, notice in the photo the little bit of blue on the belt and the broken teeth piled up under the crank.

      Good news is the coolant maintenance was right and proper as there was zero rust or residue in the cooling passages when I put the new water pump in.


    7. Junior Member
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      Jul 22nd, 2017
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      Tigs, Jettas, GTIs, CC
      09-28-2019 07:58 PM #5
      Three intake valves on left, two exhaust on right. Leftmost one should be closed like the two adjacent ones, but can't because it's bent from hitting piston.


    8. Member vdubbugman53's Avatar
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      2013 Turbo Beetle, 2003 New Beetle
      09-28-2019 08:03 PM #6
      Been there done that with the same gates "racing" belt.

      Sent from my Pixel XL using Tapatalk

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