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1999 GMC Sonoma Question: I have a 1999 Gmc s-15 sonoma with a mild engine knock on cyl #3

 

Question

Yoda1187, Hawkins, TX, July 17, 2012, 13:32
 Rookie

When the engine is fully warmed up the noise almost goes away! We have pulled the motor and dis-assembled, all wrist pins are a little loose but #3 isnt any worse than the other 3.Also all rod bearings look good, and the main bearings on each side of the #3 rod look ok. All pistons mic to be standard size. Are there any odd causes for this type of noise in this year model motor? Please HELP!!!

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  • Answer #1

    July 17, 2012, 14:54
     Technician

    Interesting one...did you use oe parts for rebuild or aftermarket?

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    Yoda1187, July 17, 2012, 16:16
     Rookie

    Haven't rebuilt, just tore down to check valves,guides,pistons,rings,etc.

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  • Answer #2

    July 17, 2012, 15:26
    Profile_thumbnail
     Master

    Why do you say #3 is the problem? How did you test,pull
    Plug wire while running? Or something else.
    1st answer ask about a rebuild,i missed that part.

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    Yoda1187, July 17, 2012, 16:20
     Rookie

    Pulled plug wire also stethoscope test its Def coming from 3 no rebuilde yet just diagnosis at this poi.

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    pushrod, July 17, 2012, 20:59
    Profile_thumbnail
     Master

    This is a puzzle,i have been doing this a long time.Most noise gets worse in a warm engine.
    I know a machinest/motor builder, been doing this a long time too.I'll ask this wizzard and get back
    if can help.Something is expanding and then fits better.

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