Incorrect coolant to water ratio will cause it to run hot too. 50/50 is always a good starting point. When I got my 560 the PO was running what appeared to be 100% coolant and had drilled a number of holes in the thermostat rim to help bring the temp down. A new T-stat and 45/55 mix did the trick.

__________________
Mike Tangas
'73 280SEL 4.5 (9/72)- RIP
Only 8,173 units built from 5/71 thru 11/72

'02 CLK320 Cabriolet - wifey's mid-life crisis

2012 VW Jetta Sportwagon TDI...at least its a diesel

Non illegitemae carborundum.