Crawl under the front of the car. See the lower hose, where it comes out of the radiator? Follow it up behind the fan, see where it attaches to the water pump? You are almost there.
Drain the radiator, disconnect the lower hose at the water pump. The inlet to the pump is held on by three 10mm bolts, remove them and tap the tube gently. Hint: the thermostat is hiding under there
. Once that tube is off, you will pull out the O-ring gasket and the T-stat should come right out. The bolt on the block side is a bit tricky to get at, using a 1/4 drive rachet, with a 6" extension did the trick for me.
Installation of the new T-stat is the reverse. The new T-stat should have a new O-ring with it, be sure to use a new O-ring and no sealant. Make sure the T-stat is oriented correctly with the vent at 12 o'clock, and that the "crown" is facing out.
Hope this helps.
'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.