I just replaced the coolant temp sensor on my 85 300D, because the gauge was jumpy, and read higher than I thought it should (absent a cooling problem, and there was no other indication of a problem). On the old sensor, the part that extends into the block below the threads, was gone. I have read before that the sensor wears out over time. Does that explain my old sensor, just worn away, or is it a different design?

I don't have any results on the new sensor yet, as I have not had a chance to drive since installing it this afternoon.

Thanks.