I don't hear it when it's necessarily hot out because it was cool today, and I only hear it when it's idling. When I rev it it goes away.
http://www.300cforums.com/forums/showthread.php?p=105391#post105391
I'm not sure if I'm experiencing the same thing as you.
http://www.300cforums.com/forums/showthread.php?p=105391#post105391
I'm not sure if I'm experiencing the same thing as you.