1999 GMC Sonoma Q&A

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

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!!! -
Answer 1
Interesting one...did you use oe parts for rebuild or aftermarket? -
Comment 1
Haven't rebuilt, just tore down to check valves,guides,pistons,rings,etc. -
Answer 2
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. -
Comment 1
Pulled plug wire also stethoscope test its Def coming from 3 no rebuilde yet just diagnosis at this poi. -
Comment 2
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. -