Originally Posted by biobenz617

I'm curious whether anyone has published data points or an equation correlating resistance vs. temperature for the engine block coolant sensor for a W123 300D-T.

That's basically the end of the road for my reckless replacement of cooling system parts (two degrease/acid flushes, new validated t-stat, new radiator, water pump impeller inspected), and I'd like to know what the resistance should be at a given temp before I spend even more $$ for a new one(yeah, I know I shoulda looked here first). I still run 100+ when running up a hill on the highway. The reason I hadn't considered it an instrument issue is that it settles around 84C when overrunning down a hill on the highway, and that is where I validated the t-stat to start opening on the stovetop, and is published at 84C in the shop manual.