I am running my car the same way FI has suggested and it works fine. Both the early 616 and the late 617 I swapped in had the two sensors in the block (coolant temp and GP).

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1979 240D- 316K miles - VGT Turbo, Intercooler, Stick Shift, Many Other Mods - Daily Driver

1982 300SD - 232K miles - Wife's Daily Driver

1986 560SL - Wife's red speed machine