The car starts and runs just normal don't hear the knock right away but with rpms the knock becomes apprent seems like after you drive and let it warm up it knocks at idle rpms as well but only when warm. Don't have any signs of head gasket or anything major on account it doesn't really affect the way it runs. Any ideas?

 

head gaskets dont make sounds . most knocks are rods or bearings ticks are usually lifter issues