98 sls running hotter than normal
 

My 98 sls is running hotter than normal. It takes about 25 minutes of driving then the temp goes to 1 oclock from 12 o clock and fluctiuates from there (a little more a little less and so forth). Mechanic couldn't find problem. Different mechanic and chilton manual suggested an air pocket but didnt tell how to drain. any ideas on how or any other ideas on this problem.

dup post...............

New thermostat and or change your coolant.
When was the last time your coolant was changed ?
It is very very important to perform regular maintenance.
Can save one thousands of dollars in the long run.