04 optra engine rattle

Hey guys and gals. I have a 2004 chevy optra. When starting the engine cold, I have an engine rattle that sounds internal. After about 30 seconds it starts to go away. After it warms up its fine. Its not a heat sheild noise, but more something internal. After driving it to opperation temp and sitting at an idle, I can hear it faintly. The last couple oil changes have shown no evidence of a problem (no metal in the filter). Any thoughts on this? It has 110,000km.

Thanks in advance
Brad

I have a 07 optra that is making the same noise, was woundering what the fix was. Is it the timing belt? I have 180 thousand on the engine, bought it used and not sure when and if the belt has been changed.

My 04 does the same thing. I believe it to be the lifters draining oil, not totally sure. I've heard adding a little ATF in the oil and running it for short trip will clean lifters etc. Then change the oil. I am going to try it myself just before my next oil change.

They sell a product for sticking lifters in the parts store. Just add it to your oil some people use transmission fluid.