Cavalier make noise when hot
 

My cavalier 2001 2.2L makes noise only when it gets hot. The noise originate at the upper part where all the pulleys and water pump are. The noise is like a grinding/rattle noise. The only thing that I can think off that is temperature dependent is the combination water pump / thermostat.
Could the noise come from the water pump?
Where else could the noise come from?
Thanks

According to the mechanic it is the timing chain that make the noise.

fix it soon before the timing chain jumps and the valves get bent.