2001 corvette 20,000 miles. Started car yesterday heard loud knocking sound about 30 seconds after starting engine. When engine warms up noise goes away. Just changed the oil to 15-30 from 5-30 any idea what this could be? Have repeated the start cold and run three times same results. Car runs fine just until warm up sounds like a can of marbles.

Bob

 

its called cold start knock...

I believe its due to the pistons slapping the cylinder walls until everything comes up to temperature. Mine started around 30K and now have 70K on it and its about the same or so...

car still runs hard so I don't even worry about it anymore <img border="0" title="" alt="[Big Grin]" src="gr_grin.gif" />

 

SOrry but I'm afraid that the headers will only amplified the cold knock. But header are STILL a great idea. <img border="0" title="" alt="[Smile]" src="gr_stretch.gif" />

 

Thanks Fireball! I know about the piston slap however I did not know it would start with so many miles. Thought I got lucky and GM actually built one that was quiet. Guess it's time for headers to drown out the engine noise. <img border="0" title="" alt="[Big Grin]" src="gr_grin.gif" />

Bob

<small>[ April 19, 2002, 12:25 PM: Message edited by: 16again ]</small>

 

</font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">Originally posted by 16again:
<strong>Guess it's time for headers to drown out the engine noise. <img border="0" title="" alt="[Big Grin]" src="gr_grin.gif" />

Bob</strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">I like your attitude. <img border="0" title="" alt="[Wink]" src="gr_images/icons/wink.gif" /> <img border="0" title="" alt="[Razz]" src="gr_tounge.gif" />

Eric