noise from engine

[Mtt22]

i ahve this weird rattle noise coming from teh top of my engine right at the front when i first start it up, someone said it was the "pollution pump", but ive never heard of that, and a 3 of the other 240's i went and looked at had the same noise, wtf is it? my car has like 135,000 km on it which is like 85,000 miles, so thats not bad, so wtf? the engine runs strong, doesnt burn oil, just has the noise, but it goes away after a while

[GotDriftS14]

hahaha, the infamous timing chain rattle! do a search and im sure u will find plenty of info on it, since it happens ALL THE TIME. i have personal experience with the rattle hehe. most people just remove the timing chain guides and the noise goes away. it usually will be loudest at startup, and when u rev it it tends to go away due to the tensioners tightening up with increased oil pressure...[correct (but dont flame) me if im wrong]...and 85k miles is usually normal to hear that noise...again, i recommend doing a search for TIMING CHAIN RATTLE, u will come up with alot of good info <img src="http://www.zilvia.net/f/iB_html/non-cgi/emoticons/thumbs-up.gif" border="0" valign="absmiddle" alt=':thumbsup:'>

oh and dont worry too much about it, its not really a serious problem so ur engine is still good. <img src="http://www.zilvia.net/f/iB_html/non-cgi/emoticons/wink.gif" border="0" valign="absmiddle" alt=';)'>

and wtf is a "pollution pump"?? &nbsp; <img src="http://www.zilvia.net/f/iB_html/non-cgi/emoticons/huh.gif" border="0" valign="absmiddle" alt=':huh:'> &nbsp;<img src="http://www.zilvia.net/f/iB_html/non-cgi/emoticons/eh.gif" border="0" valign="absmiddle" alt=':eh:'> &nbsp;<img src="http://www.zilvia.net/f/iB_html/non-cgi/emoticons/lookaround.gif" border="0" valign="absmiddle" alt=':look:'>

[BadMoJo]

Yeah, what Mike said. Its the upper chain guide. Its kinda pointless to have really. Just pull your valve cover off and remove the metal guide that sits over the chain. After that it should be all good.

[sxtasy]

GotDrifts14, What people refer to as the "smog pump" or "pollution pump" is the device that pumps air into the exhaust to aid the catalytic converter in cleaner emission. Nissan calls it the AIV system and is electric, some vehicles use a mechanical pump driven off the engine..... I removed mine....

[Apparition]

So that noise comes from a cold start, and rev's over 3k rpm? I get that wierd rattle. Wondered what that bugger was. <img src="http://www.zilvia.net/f/iB_html/non-cgi/emoticons/biggrin.gif" border="0" valign="absmiddle" alt=':D'>