03 silverado 5.3 engine knock??????

[jimmybag]

have 03 silverado with 5.3 engine, 60k on it, has a knock at cold start until warms up any ideas??

[rjeffery]

It's normal and causes no harm to the engine. Some claim to eliminate/minimize it with different oils. If you want a little more reading, do a search for "piston slap".

[knogoodidleft]

ha, there is actually a site for this http://www.pistonslap.com./ I am a synthetic advocate but maybe running some non synthetic will fill the bore, or heavier weight, eh, thinking about it, it might not fix the slap so it just started at 60k? my truck is getting close to 60k

[silverado122775]

I would not use oil any thicker than 10w30. Using thicker oils will interfere with oil flow and the oil pressure will increase. In a worn engine it may be okay to increase the viscosity of the oil because the bearing clearances have become larger.