You don't have to wait until the next coolant change to bleed air out of the system .... actually you should do it now.
It is best to do it when the coolant is warm but not hot for fear of getting burned by hot coolant.
Be aware of the advice regarding the washer underneath the bleed bolt, it easily gets dropped.
'03 E320 Wagon-Sold
'95 E320 Wagon-Went to Ex
'93 190E 2.6-Wrecked
'91 300E-Went to Ex
'65 911 Coupe (#302580)