David, the '94 S320 you speak of has an in-line 6 cyl engine, not the V-8 engine previous posters are talking about.
The in-line 6 Cyl does not have the same 'plumbing' as the V-8 engine. Both of my S320's (a '94, and a '96) have never given any problems when changing the coolant. Just 'empty the old' (at the radiator and on the passenger side of the engine block), and refill with new coolant in the overflow tank in the right-front part of the engine bay. It gurgles and such, but it fills just fine with no air-locks. Just be a little patient. It usually takes between 10 and 11 quarts of coolant to refill, if it has been fully drained.

Questions, Comments, Corrections?

Farrell