Another note on changing plugs
Since you have aluminum heads, be sure the engine is cold, like overnight cold, before removing the plugs. It's very easy to strip the threads in the head if done hot.
'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.