Once in a while when I try to start the car I get a loud screeching noise and the starter does not engage. This seems to only occur after the car has been idle for a few days. After a couple of trys the car starts normally and the problem will not repeat again until several days of being idle again. Any thoughts or similar experences. It is 2003 sl500 with 37K on it.

 

You need a new starter, the bearings/brushings are gone inside.