If your coolant ratio is correct there shouldn't be a problem running 100C but I would take out your thermostat and test for when it opens in a pot of water on the stove. It should say on the thermostat what temperature it is supposed to open at. My 190 was running at 101C almost constantly so I flushed the coolant and checked the thermostat and sure enough, it was opening at 96C instead of 85C. I got a new one from my mechanic then installed it and have been running around 90C ever since.

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Current: 1975 450SEL, 83 300D, 88 Yugo GVX, 90 300D OM603 swap, 91 F150 4.6 4v swap, 93 190E Sportline LE 3.0L M104 swap, 93 190E Sportline LE Megasquirt, 03 Sprinter, 06 E500 4Matic wagon.