Operating temperatures
It was not rhetorical - I was asking you. Why put an exhaust on. Why use better oil or other fluids. Why install/change anything that isn't available from the MB parts catalog if they did such a good job from the factory. Is that your stance on this? If so that's fine, but it's not what I believe.
. My H2O is at the same, about 194-197, but oil runs higher - lowest after warm up maybe 221 on cool day highway cruise, but most often closer to 230-233. Haven't flogged on the car too intensely yet, but curious my #s are higher than others. IIRC someone stated that post-FL cars generally run hotter than pre-FL, it this true? Anyone know why?
As stated prev, the stat (190) is to provide fast warm up so the emission control systems can be brought on line. This is why a fault will occur if the ECU has seen a longer than normal time for warmup, usually seen when stat fails, open or extreme cold as we see here. Besides all benefit is lost with the 180 as the oil temp takes longer to reach operating temp and any benefit with the 180 is lost. Larger rad(thickness) will give you what you wish to achieve.
Whomever mentioned the reason for the 195'ish t'stats was emissions, was dead on. Been this way in all cars for over 25 years. It is well known in the performance world for all cars to change the tstat out for a 180 to get more consistent performance. If the coolant temps still creep over 200 and will not drop, then it is time to start looking at better radiators



