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

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!!!

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