Wierd clicking noise

Every time i turn on my car and leave it for about 2 min this repeated clicking noise comes located somewhere between the fan and the engine block. when i rev the car the noise goes away also when i am driving, but when i stop at a light or so it comes back. Also when my engine gets warm it will go away for a while and then come back. The noise kinda sounds like some1 is shaking a tin can with a marble in it. Could any1 tell me what that problem might be.
Thx

Do you think this will apply?
http://www.son240sx.org/forums/showthread.php?t=19967&highlight=timing+chain

thx

what else could it be besides the timing beling or the guides??

clutch fan maybe. power steering pump, water pump
take the fan and clutch assembly off and see if it stops

ps be sure to tighten the water pump pulley