You might have air trapped in the system and need to burp it, or possibly you have too much coolant and not enough water. Should have about a 50/50 mix of coolant to water, or for So. Cal, might want 45% coolant to 55% water mix - that mix is holding a steady 80*C for me on the 560.
'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.