As long as the electric and vacuum portions of the servo are operating and you only bypass the coolant from the bottom section of the servo, I think all the rest of the servo functions should work. This would occur in situations where the only problem with the servo was a leaking bottom section which holds the coolant and coolant control valve.

__________________
1977 300d 70k--sold 08
1985 300TD 185k+
1984 307d 126k--sold 8/03
1985 409d 65k--sold 06
1984 300SD 315k--daughter's car
1979 300SD 122k--sold 2/11
1999 Fuso FG Expedition Camper
1993 GMC Sierra 6.5 TD 4x4
1982 Bluebird Wanderlodge CAT 3208--Sold 2/13