the running temperature was an issue for me. With cooler ambient temperatures, no concerns.. But in the summer, it could get higher that I'd like. Recently, the fuses on my auxillary fans were blown so that accouned for the running temp with the AC on in stop-n-go traffic.
I had the radiator flushed and all seems well. I'll probably re-add water wetter.
I always tell everyone that I watch the coolent temp gauge more that any other as an indicator of how the car is feeling.
Compared to my other MB's, The DOHC 606 seems to run a little hotter. Its happy spot is 1/3 above the 80 mark but averages around 1/2 to 3/4 above the tic mark. When the auxillary fuses were out, it was getting dangerously high but never in the red zone.