There have been reports of Mercedes cars repairing themselves overnight.
My 280 has also fixed herself overnight. Had a steady (2 drips per minute at idle) leak from the tensioner. One night the leak stopped, never to return - at least for the past year now.
'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.