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4.0 noise! Who is the master?

Discussion in 'General Jeep Discussion' started by Skinner1980, Nov 8, 2016.

  1. Nov 8, 2016 at 6:23 AM
    #1
    Skinner1980

    Skinner1980 [OP] New Member

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    Hello, one of my jeeps is a 2000 xj 4.0, with 206K miles. A month ago, it started making a noise. I was told it was a lifter. Well it's more of a tap/knock mixed. I was bored and took the head off, replaced lifters, and also found the torque converter bolts loose. I was ecstatic and thought I had it solved. But no. Noise gets faster with rpm and rolls down when you let off. High miles know, but still has 45psi oil pressure. I've got a 96 xj that recently evolved bottom end knock. The 00 doesn't sound like rod or main noise. Could it be a cracked flywheel that I can't see without removal??? A wrist pin??? I need a 4.0 specialists help! Oh, also, the kicker.... the last 2 mornings, it's been 30°, and it's been almost silent?!
     
  2. Nov 8, 2016 at 6:27 AM
    #2
    chris4x4

    chris4x4 With sufficient thrust, pigs fly just fine Moderator

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    Welcome! I'm not good at trouble shooting the 4.0, so hopefully someone else will pop in to help.
     
    Skinner1980 [OP] likes this.
  3. Nov 8, 2016 at 7:47 AM
    #3
    Paul123

    Paul123 Active Member

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    Out wheeling
    Vehicle:
    94 zj longarms locked/locked
    Long arms, front and rear bumpers, lockers, dana 44 rear skidded and trussed, 242 tcase swap, leather interior swap, etc...
    Same thing happened to me. Ended up being a bent push rod. Ended up bending so much it broke in half
     
  4. Nov 10, 2016 at 7:03 PM
    #4
    jwp313

    jwp313 New Member

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    I have a 2000 with 90,000 on it and just started the same thing, mine is a piston knock, was getting quieter as it warmed up, but broke the piston tonight, now need motor, if it quiets as it warms up its usually a piston knock, pistons swell as they get hot. If it gets worse as it warm that's usually the lower end, rods or main knocks get worse as the oil thins, either way its a progressive disease and is only going to get worse
     
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